NASA Technical Memorandum 86390

i NASA-TM-86390 19860002180

Active and Passive Microwave Measurements in Hurricane .A~.llen

Victor E. Delnore, Gilbert S. Bahn, William L. Grantham, Richard F. Harrington, and W. Linwo<?d Jones

NOVEMBER 1985

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https://ntrs.nasa.gov/search.jsp?R=19860002180 2020-05-25T05:17:15+00:00Z

NASA Technical Memorandum 86390

Active and Passive Microwave Measurements in Hurricane Allen

Victor E. Delnore and Gilbert S. Bahn

PRC Kentron, Inc. Hampton, Virginia

William L. Grantham and Richard F. Harrington

Langley Research Center Hampton, Virginia

W. Linwood Jones

Harris Corporation Melbourne, Florida

NI\S/\ National Aeronautics and Space Administration

Scientific and Technical Information Branch

1985

CONTENTS

ACKNOWLEDGMENTS ................................................................ SYMBOLS AND ABBREVIATIONS

1. SUMMARY ..................................................................... 2. INTRODUCTION ................................................................ 3. MISSION DESCRIPTION ......................................................... 4.

5.

6.

MICROWAVE SENSORS ........................................................... 4.1 4.2

Stepped Frequency Microwave Radiometer •••••••••••••••••••••••••••••••••• Airborne Microwave scatterometer ••••••••••••••••••••••••••••••••••••••••

AIRCRAFT SENSORS ............................................................ 5.1 Inertial Navigation Systems ••••••••••••••••••••••••••••••••••••••••••••• 5.2 Aircraft Radars ..••..••.••.•••..••..•.••••.••..••.••••••..•••••••••.•••.

MISSION RESULTS ............................................................. 6.1

6.2

Introduction and Definitions •••••••••••••••••••••••••••••••••••••••••••• 6.1.1 Eyewall Penetrations (Passes) and Transits •••••••••••••••••••••••• 6.1.2 partitioning of Data •••••••••••••••••••••••••••••••••••••••••••••• 6.1.3 Time Lines •••••••••••••••••••••••••••••••••••••••••••••••••••••••• Aircraft INS and Radar Measurements ••••••••••••••••••••••••••••••••••••• 6.2.1 INS Wind Speed and Direction •••••••••••••••••••••••••••••••••••••• 6.2.2 Rain Rate From Aircraft Radars ••••••••••••••••••••••••••••••••••••

v

vii

2

3 4 4

5 5 5

5 6 6 6 6 6 7 8

6.3 Microwave Sensor Measurements ••••••••••••••••••••••••••••••••••••••••••• 9 6.3.1 Radiometer Calculations ••••••••••••••• !........................... 9 6.3.2 Scatterometer Calculations •••••••••••••••••••••••••••••••••••••••• 11

6.4 Geophysical Comparisons ••••••••••••••••••••••••••••••••••••••••••••••••• 12

7.

8.

9.

DISCUSSION OF RESULTS Use of 3000-m INS 7.1

7.2

....................................................... Winds as Estimator for Sea-Level Winds ................

Radiometer 7.3 Radiometer

Wind Speed Rain Rate

................................................... .................................................... 7.4 Scatterometer Wind Vector ............................................... CONCLUSIONS ................................................................. REFERENCES ..................................................................

TABLES ......................................................................... FIGURES ........................................................................ APPENDIX A - SENSOR DESCRIPTIONS ...............................................

A.1

A.2

Sensors ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• A.1 .1 Radiometer •••••••••••••••••••••••••••••••••••••••••••••••••••••••• A.1.2 Scatterometer ••••••••••••••••••••••••••••••••••••••••••••••••••••• Sensor Footprint Geometry •••••••••••••••••••••••••••••••••••••••••••••••

iii

13 13 14 14 15

16

17

19

22

81 81 81 82 86

APPENDIX B - SCOPE AND FORMAT OF ARCHIVED DATA ................................. 97 B.l INS and Radiometer Data Files ••••••••••••••••••••••••••••••••••••••••••• 97 B.2 Scatterometer Data Files •••••••••••••••••••••••••••••••••••••••••••••••• 97 B.3 Rain Radar Data Files ••••••••••••••••••••••••••••••••••••••••••••••••••• 98 B.4 structure of Archived Data Tapes •••••••••••••••••••••••••••••••••••••••• 98

APPENDIX C - RECORD OF ADDITIONAL INS AND RADIOMETER DATA ...................... 103

iv

ACKNOWLEDGMENTS

The airborne microwave remote sensing of Hurricane Allen was a considerable undertaking. This field experiment and the subsequent analysis reported here were possible only through the efforts of several persons with whom the authors have had the pleasure of working. R. W. Burpee, D. P. Jorgensen, F. D. Marks, and H. E. Willoughby, of the NOAA National Hurricane Research Laboratory, contributed calcula­tions pertaining to the behavior of the storm. H. W. Davis, F. J. Merceret, and T. Schricker, of the NOAA Research Facilities Center, assisted in the interpretation of data from the aircraft digital systems. C. L. Britt and P. R. Schaffner, of Research Triangle Institute (RTI), and K. K. Kiley, formerly of RTI, provided the post-mission recovery and initial processing of the microwave data tapes. R. H. Couch, A. E. Cross, J. C. Fedors, D. P. Oliver, and H. F. Thornton, of the NASA Langley Research Center CLaRC), A. L. Jones, formerly of LaRC, and C. A. Lipp, of PRC Kentron, Inc., developed, built, installed, and prepared for flight many of the subsystems of the two microwave instruments. Also, Mr. Couch and Mr. Oliver assisted in the operation of those instruments during the penetrations of Hurricane Allen.

C. T. Swift, of the University of Massachusetts, and P. G. Black, of the National Hurricane Laboratory, were responsible for much of the interagency coordina­tion which resulted in the Hurricane Allen field experiment and subsequent analysis. Of particular note is Dr. Black's contribution of the NOAA rain radar calculations and navigational data.

v

A,B

c

f

G

h

L

N

R

z

SYMBOLS AND ABBREVIATIONS

footprint dimensions perpendicular to and along flight path, respectively

effective area of antenna footprint on surface

speed of light

frequency

antenna gain (dimensionless)

aircraft altitude

miscellaneous waveguide losses (dimensionless)

number of independent samples

received and transmitted power, respectively

slant range

antenna brightness temperatures at the four radiometer frequencies (4.498, 4.994, 5.586, and 6.594 GHz)

flight level INS wind speed

flight level radiometric wind speed

ground speed of aircraft

output voltage of integrator during calibration

output voltage of integrator during surface observation

reflectivity factor (dimensionless)

programmable attenuation during calibration (dimensionless)

receiver calibration loop attenuation (dimensionless)

programmable attenuation during surface observation (dimensionless)

Doppler bandwidth of received power

effective pencil-beam antenna width

incidence angle

wavelength

normalized radar cross section

vii

x

opacity due to rain and clouds (dimensionless); also, integration time, sec

horizontal angle between wind direction and scatterometer antenna beam

subscripts:

H

L

regime H

regime L

Abbreviations:

AID

GMT

IF

IFOV

INS

NHRL

NOAA

SASS-1

analog to digital

Greenwich Mean Time

intermediate frequency

instantaneous field of view

inertial navigation system

National Hurricane Research Laboratory

National Oceanic and Atmospheric Administration

Seas at geophysical algorithm relating 0 0 to wind vector

TDA tunnel-diode amplifier

TWT traveling wave tube

viii

1. SUMMARY

This report summarizes the NASA Langley Research Center analysis of the airborne microwave remote sensing measurements in Hurricane Allen obtained on August 5 and 8, 1980. The primary objective of this report is to evaluate the performance of the microwave instruments in a severe storm. Explanation of the meteorological aspects of the storm itself, based on this and similar data sets, is under way at the NOAA National Hurricane Research Laboratory and is not included here.

The NASA instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA C-130 aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm-sea value. The rain rate (actually liquid water content of the air column) is obtained from the difference between antenna temperature increases measured at two frequencies, after correcting for other dispersive effects. The wind vector is determined from the sea­surface normalized radar. cross section measured at several azimuths.

Comparison wind data were provided through the use of the inertial navigation systems (INS) aboard both the C~130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating at altitudes between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. It was the original intent that the microwave-derived surface winds would be compared with surface winds calculated with a planetary boundary layer model using as input winds measured with the INS aboard the P-3 at 500 m (the assumed nominal top of the boundary layer)~ however, extreme turbulence forced that aircraft to fly at 1500 m most of the time. Therefore, the surface winds obtained with the two microwave instruments could be compared only with each other and with the flight-level winds. Nevertheless,. several important conclu­sions have been drawn from these comparisons.

The analysis shows that the radiometer accurately predicts flight-level wind speeds and rain rate (liquid water content) and that the scatterometer produces well­behaved and consistent wind vectors for the rain-free periods. Analysis of scatter­ometer data obtained in the presence of rain (which attenuates the scatterometer signal) has not been completed and is not reported here.

2. INTRODUCTION

Development of microwave instruments for remote sensing of environmental vari­ables has been under way for several decades, involving many government agencies, universities, industry, and private laboratories, both in the United States and abroad. Microwave scatterometers, which are active devices, have been employed to detect and measure sea ice, sea-surface wind vectors and large-scale waves, and other features of the Earth's surface (Jones et ale 1982). Microwave radiometers, which are passive devices, have been applied to the measurement of sea ice, soil moisture, atmospheric water vapor, and ocean surtace temperature, salinity, and wind speed. The NASA Langley Research Center has developed both types of sensors for a wide range of remote sensing experiments.

Aircraft reconnaissance of hurricanes has been conducted by the National Oceanic and Atmospheric Administration and by the Department of Defense since World War IIi a brief history of these programs is given by Frey (1980). until the early 1970's, the aircraft served primarily as a carrier of meteorologists and of in situ sensors such as barometers, accelerometers, navigation instruments (including radar), and air sam­plers into the storm. However, during the past decade, the aircraft has also func­tioned as a platform for remote sensing devices. The early development of these efforts may be traced by consulting Ross et ale (1974), Black and Schricker (1978), Kaupp and Holtzman (1979), and Kidder, Gray, and Vonder Haar (1980).

In 1980, NOAA and NASA conducted a cooperative program to improve the reli­ability of rain rate and surface wind vector estimates by applying microwave remote sensing technology. This program resulted in the Hurricane Allen field measurements and the subsequent analysis reported herein.

3. MISSION DESCRIPTION

The 1980 hurricane season was highlighted by Hurricane Allen, which stands as the most intense North Altantic storm ever penetrated by aircraft. Lawrence and Pelissier (1981) discuss the storm and its impact. The meteorological aspects of the storm itself are discussed by Willoughby, Clos, and Shoreibah (1982). On August 5 and 8, 1980, the NASA Langley Research Center's Ku-band airborne microwave scatterom­eter and C-band stepped frequency microwave radiometer were flown into Hurricane Allen aboard a NOAA C-130 aircraft (fig. 1) as part of a three-aircraft experiment conducted by the NOAA National Hurricane Research Laboratory (NHRL). Ocean surface normalized radar cross section and brightness temperature were measured with the scatterometer and radiometer, respectively. These data have been analyzed and com­pared with measurements from the aircraft data systems to evaluate the ability of the microwave instruments to estimate surface wind speeds and directions and rain rates within the storm. Actually, it is atmospheric liquid water content between the sea surface and the aircraft that is measured by the radiometer. For convenience, this is represented here as an equivalent rain rate for an air column height of 3000 m. The specific purposes of this mission were (1) to obtain data for the improvement of the geophysical algorithms for both microwave instruments and (2) to demonstrate the feasibility of combined active and passive microwave remote sensing techniques at high altitudes to obtain information that could, at least until the time of Hurricane Allen, be obtained only at considerable risk from aircraft at low altitudes.

A preliminary report, based on a limited amount of the data, appeared in Science (Jones et al. 1981). At the time of publication of that article, plans to archive the entire data set had not yet been developed. The primary objectives of this report are to evaluate the performance of the microwave instruments and to archive data for all passes through Hurricane Allen.

The microwave sensors were flown on the C-130 at an altitude of approximately 3000 m. A low-altitude P-3 (at 500 to 1500 m) flew beneath the C-130 and generally along the same flight lines. This low-altitude aircraft was intended to measure winds near the top of the hurricane planetary boundary layer. Another NOAA P-3 flew at 5000 m. All three aircraft carried nose, tail, and/or lower fuselage radars, from which composites of rain rate were later constructed.

The vertical stacking of the three aircraft is shown schematically in figure 2. The actual flight altitude histories for the eyewall penetrations by the two lower altitude aircraft are given in figure 3. The C-130 maintained a certain barometric

2

altitude; therefore, its actual (geometric) altitude varied as shown. The flight paths with respect to the storm's moving center are presented in figures 4 and 5.

The time-dependent track of the storm center was determined by NHRL through the use of cubic spline equations fitted to the positions of atmospheric pressure minima. These pressure minima were located by triangulation from successive aircraft posi­tions along each airplane's passes through the storm. For each aircraft and for each day, separate equations were generated for latitude and for longitude. For purposes of this report, the inertial navigation system (INS) of the P-3 at 500 and 1500 m and that of the C-130 at 3000 m were considered equally reliable, so that the storm cen­ter location at any instant was taken as the average given by the two sets of equa­tions. From this procedure, the general position of the storm center during August 4-10, 1980, was determined and is presented in figure 6 with the locations of aircraft penetrations given.

The number of eyewall penetrations made by the two lower altitude aircraft on each flight day is given below:

No. of eyewall penetrations by -

Date" P-3 C-130

(500 and 1500 m) (3000 m)

August 5 16 16 August 8 16 14

Because of the differences in ground speed, the P-3 moved ahead of the C-130 on both days. To allow data from the two aircraft to be compared, pass names were assigned to identify 26 pairs of penetrations. Table 1 gives start and stop times of all paired passes. The paired passes are numbered chronologically from 1 to 26, and the letter N, S, E, or W is appended to indicate the general bearing of each pass track from the storm center.

4. MICROWAVE SENSORS

NASA Langley Research Center microwave instruments used during the Hurricane Allen flights were the stepped frequency microwave radiometer and the airborne micro­wave scatterometer. (These instruments and their footprint geometry are described in detail in appendix A.) Wind speed is calculated from the radiometer data through knowledge of the increase in sea-surface brightness temperature (measured with the radiometer) above the calm-sea value estimated by regression on part of the August 8 data. Rain rate (actually liquid water content of the air column) is obtained from the difference between antenna brightness temperature increases (over calm-sea values) measured at two frequencies, after other dispersive effects are accounted for. Wind vector is calculated from the sea-surface normalized radar cross section (ao ) measured with the scatterometer for several azimuths, by using the SASS-1 geophysical algorithm to relate aO to wind vector.

The relationship between brightn~ss temperature and wind speed is shown in figure 7(a) and between brightness temperature and rain rate in figure 7(b) for the

3

first pass through the hurricane. A uniform increase in antenna brightness tempera­ture for all four radiometer frequencies would indicate higher wind speed and no rain, while a dispersion in antenna brightness temperature over the various frequen­cies would indicate the presence of rain. Most of the features on the brightness temperature plot (center panels, figs. 7(a) and 7(b» show a combination of rain and wind and are keyed to the labeled features on the rain radar composite shown in the upper panels of figures 7(a) and 7(b).

4.1 stepped Frequency Microwave Radiometer

Passive microwave remote sensing measurements of sea-surface wind speed and rain rate were derived from antenna brightness temperatures measured with the stepped fre­quency microwave radiometer. The radiometer is a balanced Dicke-switched, noise feedback radiometer and was operated during the Hurricane Allen flights at 4.498, 4.994, 5.586, and 6.594 GHz with a 50-MHz bandwidth and 1.0-second integration time, using a circularly polarized, corrugated horn antenna (Harrington 1980).

The radiometric antenna brightness temperature of the sea surface, as measured with the radiometer, is the sum of the cosmic background radiation and the radiation from the atmosphere (both reflected from the sea surface) and the radiation emitted from the sea surface itself. All three are attenuated by the intervening atmosphere.

The amount of electromagnetic radiation emitted by the sea surface is affected by the surface roughness, breaking waves, and foam, all attributed (to first order) to the force of the wind. Because rain is only weakly attenuating at the C-band microwave frequencies used, the surface emission variation due to wind speed change at the ocean surface is detectable from flight altitudes above a rain layer.

Furthermore, microwave emission by rain is dispersive, varying as an inverse power of electromagnetic wavelength. Therefore, simultaneous measurement of wind speed and rain rate is possible whenever the instrument is operated at more than one frequency (as was done 85 percent of the time). This dispersion due to rain is shown in figure 7(b), with the heaviest rain near the radius of maximum winds (points A and D on the rain radar composite).

4.2 Airborne Microwave Scatterometer

Active microwave remote sensing measurements of surface wind speed and direction were obtained during the Hurricane Allen flights with the airborne microwave scatter­ometer. The 14.6-GHz scatterometer measures the normalized radar cross section (ao ) of the ocean surface at various incidence and azimuth angles. The strength of the radar backscatter is a function of the wind-driven capillary wave amplitude, which is proportional to the wind stress at the sea surface. The radar backscatter is aniso­tropic in azimuth1 therefore, wind direction can also be derived from scatterometer measurements. The dual-linear polarized parabolic antenna for the scatterometer is mounted pn a two-axis servo-controlled pedestal to provide independent elevation and azimuth pointing. The pointing of the antenna and all other functions of the scat­terometer were under the control of a programmable microprocessor. During the Hurricane Allen flights, aO was measured with the antenna in one of three basic modes as described in table 2: fixed azimuth and elevation (mode 8), fixed azimuth and varying elevation (mode 3), and varying azimuth and fixed elevation (mode 2). The remaining numbers (1 and 4-7) identify calibration modes.

4

wind vector (both speed and direction) is best determined from radar cross sec­tions obtained with the scatterometer in mode 2, in order to accumulate aO measure­ments over a range of azimuths. The SASS-1 geophysical algorithm, described by Jones et ale (19B2) and Schroeder et ale (19B2), may produce alias wind vectors, differing primarily in wind direction. One of these directions is usually within a few degrees of the true surface wind. In a cyclonic storm such as Hurricane Allen, the wind's general direction can be estimated if the bearing of the measurement point from the storm center is known. (The bearing plus 90° equals the approximate wind direction, ignoring friction.) This fact, along with the INS measurement of wind direction, is used in selecting from among the aliases yielded by the wind vector algorithm.

Further discussions of wind vector determination from backscatter measurements are available in Jones and Schroeder (1978) and Thompson, weissman, and Gonzalez (1983). Moore et ale (1982) have evaluated the effect of precipitation on a Ku-band scatterometer, and Dome (1975) discusses the choice of frequency for a wind-measuring scatterometer. L-band measurements of sea-surface backscatter in hurricane force winds are reported in Weissman, King, and Thompson (1979).

5. AIRCRAFT SENSORS

5.1 Inertial Navigation Systems

Flight-level wind speed and wind direction data are provided by the INS as part of the flight navigation system of each aircraft. Also provided are the altitude, roll, pitch, yaw, and ground speed; all are needed in the computation of aO •

Merceret and Davis (1981) fully describe the P-3 INS, and Haydu and Darby (1983) describe the C-130 system.

5.2 Aircraft Radars·

The two P-3's were equipped with rain-rate-measuring -nose radars (120° hori­zontal scan), lower fuselage radars (360° horizontal scan), and tail radars (360° vertical scan). Because of power requirements, only two radars could be operated simultaneously aboard each airplane. The C-130 at 3000 m was equipped with one 120° horizontally scanning nose radar. Data from the aircraft radars were used by NHRL to construct pass-by-pass profiles and 4-hour averages of rain rates derived from radar reflectivity in the air volume. Of the various rain radar composites, those made from the low-altitude P-3 data were the most appropriate for comparison with the radiometer rain rate, as will be shown in section 6.

6. MISSION RESULTS

This section presents definitions, the organization of the data, and the results of comparison between the microwave measurements and corresponding aircraft measure­ments. Digital tapes containing the data are available from the National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161. Requestors should ask for Data Tape Supplement to NASA TM-B6390. The format of the digital tapes is described in appendix B.

5

6.1 Introduction and Definitions

6.1.1 Eyewall Penetrations (Passes) and Transits

All data except the averaged composites from the rain radars are identified by pass or transit name. A pass is defined as one excursion of the two lower altitude aircraft between a point on the periphery of the storm and a point near the storm center, with travel generally along a radial in either direction. A pass name was assigned to every eyewall penetration made jointly by the C-130 at 3000 m and the P-3 at 500 to 1500 m. Because of differences in ground speed, the two aircraft did not penetrate the eyewall at the same time, but for each pass were flying along nearly the same radial and in the same direction. Pass names are chronologically numbered to 12 for August 5, and 13 to 26 for August 8, 1980, and have a letter (N, S, E, or W) assigned to indicate the general bearing of the aircraft from the storm center. A list of pass pairs is given in table 1.

A transit is defined as any excursion around the periphery of the storm or an excursion through the storm center for which no obvious pass pairing can be assigned. For each of the two lower altitude aircraft on each day, the transits are numbered chronologically and are distinguished from the pass numbers by a T, for example, T1, T2. Data from the transits are displayed in appendix C.

6.1.2 partitioning of Data

INS and radiometer measurements were originally obtained and recorded about sec apart. These were then time-averaged into bins of 0.004 hr (14.4 sec), which

corresponds to aircraft movement of slightly less than 1 n.mi. at the ground speeds experienced during Hurricane Allen. The scatterometer data were also averaged into 14.4-sec bins except that a bin was closed early and a new bin started if the antenna incidence angle or azimuth angle changed by more than 5° or 30°, respectively. Scan settings for elevation and azimuth 5° and 30° apart, respectively, were chosen in flight. Any instantaneous differences between the actual angles and the chosen angles were the result of aircraft motion. Inspection of the data reveals that these differences were nominally 2° or less, for either elevation or azimuth. Means for each parameter (INS wind speed, INS direction, latitude, longitude, radiometric brightness temperature for each radiometer frequency, scatterometer normalized radar cross section (0

0), and antenna angles) were calculated for each bin.

6.1.3 Time Lines

Figures 8 and 9 are plots, on a coarse time scale, of instrument status, pass name, transit name, and certain other information. These figures indicate the opera­tion of sensors in various configurations during the various passes and transits.

6.2 Aircraft INS and Radar Measurements

The INS and rain radar measurements are described in this section. INS wind speeds obtained with the C-130 at 3000 m were compared with those from the P-3 that flew at either 500 m or 1500 m. This was to establish the C-130 INS winds as a stan­dard with which those calculated from the microwave remote sensing instruments (the scatterometer and the radiometer, both aboard the C-130) could be compared. By using

6

the C-130 INS winds as the standard, rather than those from the P-3, the two-aircraft collocation problem was eliminated.

Wind speed data from the second P-3 (flying at 5000 m) were not used in this study. Therefore, no further mention will be made of data from that aircraft, and "p-3" will hereafter mean the low-altitude (500 to 1500 m) aircraft only.

6.2.1 INS Wind Speed and Direction

The flight-level wind speeds measured on August 5 with the INS's aboard the P-3 (at 1500 m) and the C-130 (at 3000 m) are compared in figure 10. The wind speeds for the various passes are superimposed in figure 10(a) for the P-3 and in figure 10(b) for the C-130. To eliminate azimuthal asymmetry, the wind speeds have been corrected for the forward motion of the storm, and the resulting tangential wind speeds are plotted against distance from the storm center. The peak in wind speed at 20 n.mi. is clear at both altitudes. Figures 10(c) and 10(d) are scatter plots to compare the INS wind speeds at both altitudes. This comparison considers two regions: within the eyewall (fig. 10(c» and outside the eyewall (fig. 10(d».

Figure 11 presents analogous results for August 8. The peak in wind speed is observed at 9 n.mi. from the storm center. These distances to maximum wind speed agree with those given by Willoughby, Clos, and Shoreibah (1982). In the outer re­gions of the storm, the P-3 data for some quadrants show a stronger upturn than the C-130 data. As will be shown in the next section, this upturn was also seen with the microwave instruments for the same quadrants.

INS wind speeds for the two passes at 500 m made on August 5 by the P-3 are com­pared in figure 12 with those made comparably by the C-130 at 3000 m (same flight track, about half an hour later).

The reason the data are divided into two storm zones for the scatter plots is that strong wind gradients inside and near the eyewall cause large differences in measured aircraft winds when small errors are made in relative aircraft location. The winds shown in the scatter plots of figures 10, 11, and 12 were not adjusted for the forward motion of the storm, because to do so would decrease the range of wind speeds available for comparison. All the data contained in the scatter diagrams of figures 10, 11, and 12 were obtained within 50 n.mi. of the storm center. This limit was imposed because, beyond that distance, vertical similarity in the INS winds was found to diminish.

Flight-level wind directions measured with the INS aboard each aircraft are presented with the wind speeds on a pass-by-pass basis later in this report (section 6.4).

A study was conducted to determine the importance of collocating the wind mea­surements accurately from each aircraft. Small navigational errors (1 to 3 n.mi.), typical in INS navigation, can cause large differences in wind values near the eye­wall because of the strong radial gradients. Knowledge of the along-track coherence of the winds is necessary in the comparison of the microwave-derived winds with those of the INS. This is because the footprint of the scatterometer is not directly below the C-130 and because tilt of the eyewall causes the radius of maximum winds to in­crease with altitude. The latter causes horizontal collocation errors near the eye­wall (between the radius of maximum surface winds and that for flight-level winds) to

7

have significant effects. Therefore, INS-microwave comparisons in the vicinity of the eyewall were avoided.

To determine the effect of collocation error on the comparison of wind speeds from any two instruments, the radial coherence of wind speeds from a single instru­ment was studied first. The C-130 flight-level INS wind record for pass 1N was used to form two identical distance-ordered series. These identical wind records were then plotted against each other with one record successively shifted in 1 n.mi. in­crements. The resulting scatter diagrams are shown in figure 13(a) for measurements inside the eyewall and in figure 13(b) for measurements outside the eyewall. The effect of collocation error on the i~terpretation of wind speed data is much greater inside the eyewall than outside. A similar result is seen in figure 14, in which scatter diagrams for pass 2S are shown. (Diagrams for zero shift are not shown, since all points would necessarily lie on the line of perfect agreement.)

Because of the great sensitivity to collocation error inside the eyewall, sug­gested by figures 13 and 14, pass-by-pass comparison between the microwave-derived winds and the INS winds is restricted to the region outside the eyewall. Those comparisons are presented in section 6.4.

6.2.2 Rain Rate From Aircraft Radars

Atmospheric liquid water reflectivity data from the NOAA aircraft radars were used for evaluating the ability of the radiometer to measure rain rate. Since the radiometer was aboard the C-130 (at 3000 m) and was sensitive to the amount of liquid water in the air volume below, the reflectivity data from the lower fuselage radar on the low altitude P-3 were chosen as the most suitable for comparison. The radar mea­surements therefore did not include the rain between the flight levels of the P-3 and the C-130, which the radiometer did see. (Recall from fig. 2 that there was no equivalent rain radar on the C-130.)

To minimize the effects of noise, time composites of the single-sweep data were constructed for each P-3 pass through the storm (Marks 1981). These in turn were combined into several P-3 multipass composites in order to further decrease the mea­surement uncertainty. The C-130 flight tracks were then laid over the P-3 radar mUltipass composites to obtain profiles of reflectivity, ordered according to C-130 along-track distance. The reflectivity values were converted to radar rain rate in mm/hr from

Radar rain rate = (Z/300)-1.35 (1)

where Z is a unitless reflectivity factor (Jorgensen and Willis 1982). A rigorous treatment of Z may be found in Rogers (1976).

Rain rate profiles were obtained for C-130 passes 1 to 6 and 13 to 25. Each is paired with its respective radiometer rain rate profile in section 6.4. Radar rain rate profiles for August 5 and 8, averaged over 360 0 in azimuth, are presented in figure 15. Profiles averaged over the indicated azimuth ranges for August 5 and August 8 are given in figures 16 and 17. Rain rate differs significantly from quadrant to quadrant.

8

Note that for most hurricane research flights, underwing instruments are used for obtaining the distribution of rain droplet sizes. This distribution enters into the radar rain calculation. The results for Hurricane Allen were degraded by an unknown amount because the underwing instruments failed.

6.3 Microwave Sensor Measurements

6.3.1 Radiometer Calculations

Rain rate.- Rain rate is calculated from the difference in brightness tempera­ture at two radiometer frequencies, by the method of Gloersen and Barath (1977). For the altitude and frequencies at which the radiometer was operated, the Gloersen and Barath equation for rain rate in mm/hr becomes

Radiometer rain rate = [(106.84. + 27.087)1.2 - 52.398]0.833 (2)

where ., the unitless opacity due to both rain and clouds, is related to the differ­ence in the brightness temperatures at two frequencies through

T = 0.01091 [TA,i - TA,j - ~T(0.996)] - 0.0075 (3 )

where TA i and T ' are the brightness temperatures at any two radiometer fre­quencies,' 8r is t~~Jobserved temperature difference in no-wind, no-rain brightness temperatures at the two frequencies, 0.996 is a correction for the atmospheric atten­uation due to 02' and 0.0075 is the opacity due to ciouds. The no-wind, no-rain antenna temperatures for the various frequencies were obtained during an August 4 flight from Miami to San Juan. The aircraft flew over a s"trip of 150 n.mi. between Long and Mayaguana Islands in the Bahamas, known to be at a nearly time-invariant sea-surface temperature of 28.0° to 28.2°C (peter G. Black, NHRL, personal communica­tion). Radiometer rain rates are computed using equations (2) and (3), and are presented as pass-ordered data in section 6.4.

Alternative methods for estimating rain rate are possible, using TA 1,/TA ' , ' , J

rather than TA , - TA '. One such method has been formulated by SW1ft (Jones et ale 1981). ,1,J

Wind speed.- The relationship between wind speed and brightness temperature, even in the absence of the dispersive effects of clouds and rain, is nonlinear. Apparently there are two nearly linear regimes (Harrington 1980), although the transition between these two may comprise a third one. In the lower wind speed regime (regime L), brightness temperature increases only slightly with increasing wind speed. In the higher wind speed regime (regime H), brightness temperature increases substantially with increasing wind speed. Lower bounds on regime H were assigned by inspection of figure 18(a), which is a plot of brightness temperature (TA 1) against C-130 flight-level INS wind speed (U, ). The data include only those , , , ,1ns, p01nts IY1ng between 10 and 50 n.m1. from the storm center and for wh1ch the computed rain rate was less than 6 mm/hr. This rain rate limit is a trade-off between a lower value, which would have decreased dispersion, and a higher value, which would have

9

permitted higher wind speeds (because the highest wind speeds were accompanied by substantial rain). Simply by inspection, any data point for which the wind speed was less than 22.5 m/sec, or the brightness temperature was less than 120.7 K, was assigned to regime L. All other data points (Wind speed> 22.5 m/sec and TA > 120.7 K) were assigned to regime H.

For all brightness temperature measurements meeting the above criteria for regime H, stepwise regression calculations were performed for all data from August 8 between 10 and 40 n.mi. from the storm center. The C-130 INS wind speeds were re­gressed against TA,1 and (TA,4 - TA,1)' where frequency 1 is 4.498 GHz and fre­quency 4 is 6.594 GHz. The resulting equation for predicting flight-level wind speed from radiometric measurements is, in meters per second,

Ur,H = 1.065TA,1 - 0.616(TA,4 - TA,1) - 99.66 ± 3.4

Since the difference ~T in no-wind, no-rain values of TA,1 equation (4) becomes, after some rearranging,

and

1.065[TA,1 - 0.5784(TA,4 - TA,1) - 93.58] ± 3.4

1.065[TA,1 - 0.5784(TA,4 - TA,1 - 2.24) - 94.87] ± 3.4

The adjustment of brightness temperature due to rain is thus given by

T~,1 = TA,1 - 0.5784(TA,4 - TA,1 - 2.24)

so that equation (6) becomes

Ur,H = 1.065(Ti,1 - 94.87) ± 3.4

The prime indicates adjustment for the effects of rain.

(4)

is 2.24 K,

(5)

(6)

(7)

(8)

This separation into two equations, (7) and (8), is necessary because the scat­ter in the data of regime L precludes definition of a rain adjustment. The rain adjustment must be the same for either regime, so equation (7) can be applied to regime L. Figure 18(b) presents the results of the stepwise regression, showing the computed Ur H plotted versus Uins. The results are satisfactory because of the cohesive structure of the storm on August 8, which assures a more correlated propor­tionality between Uins and the surface wind speed that resulted in the measured brightness temperature values. The data scatter can be attributed (in part) to the microscale structure of the winds.

10

Figure 18(c) shows adjusted values of brightness temperature, Ti,1 plotted against Uins for regime L. Included are all data points obtained from 0 to 3 and 10 to 87 n.mi. from the storm center. Points lying between 3 and 10 n.mi. were excluded because of the tilt of the hurricane eyewall. The equation assigned for regime L is

6.35(T' 1 - 116.36) A, (9)

Figure 18(d) shows the results of this equation plotted against the corresponding INS wind speed.

The two linear equations, (8) and (9), produce identical values of 27.5 m/sec for wind speed at adjusted brightness temperatures of 120.7 K, the demarcation point between the two equations. Figure 19(a) merges the results of the two equations, each applied to the data points in its respective regime. (Those data points in regime H that lie beyond 40 n.mi. from the storm center are not included.) Fig-ure 19(b) similarly merges the two sets of adjusted brightness temperature data. Figures 19(c) and 19(d) show, for August 5 and 8, respectively, scatter plots for all passes, relating Ur to Uins. The data for August 5 are restricted to between 20 and 40 n.mi. from the storm center, and those for August 8 to between 10 and 40 n.mi. The restrictio~ for August 5 results in only one equation being represented in figure 19(c), that for TA,1 > 120.7 K (regime H).

6.3.2 scatterometer Calculations

Azimuth scans.- Since 00 is such a strong function of both azimuth (with re­spect to the wind direction) and incidence angle, the scatterometer data had to be partitioned according to those parameters. The primary operating mode for the scat­terometer was the azimuth scan (mode 2 in table 2). These data were partitioned first by incidence angle (19°, 39°, and 52°), then by azimuth (bins of not more than 30° change). No bin was allowed to contain data obtained more than 14.4 sec apart (this limit was explained in section 6.1.2). Mean values of 00 , incidence angle, and azimuth from enough successive bins to give an azimuth spread sufficient for proper operation of the SASS-1 geophysical algorithm were then used to compute wind vectors. The output of the algorithm includes the aliases described in section 4.2. Some of the mode 2 scatterometer measurements made during Hurricane Allen had to be eliminated because of obvious instrument problems (due to a faulty polarization change-over switch) or severe beam attenuation (due to precipitation). In the pres­ent study, a radiometer rain rate estimate of 2 mm/hr or less was the basis for estimating when the scatterometer data were nominally rain free.

The result of this editing is that all scatterometer data for August 5 (exces­sive rain) and all horizontal-polarization data on August 8 (instrument problem) were eliminated. Sufficient data were obtained on August 8 to form 34 values of derived wind vector. These are listed in table 3, together with simultaneously obtained results from the INS and the radiometer.

The partitioned 00 data for the· first pass on August 8 are shown in figure 20.

Each data bin is represented by a square, and the bins for each solution are dis­played together on a single polar plot. On these plots, true north is always to the top, and the tick mark on the outer circle indicates the flight-level wind direction

11

measured with the C-130 INS. The arrow indicates the wind direction of the algorithm-returned alias closest in direction to the INS and simultaneously chosen because of quadrant (see section 4.2). The circle itself represents a aO value 10 dB higher than the center (i.e., Radius = 10 dB). The absolute aO scale may vary from plot to plot, so the value at the center is given at the upper right. Each square represents one bin, plotted at its mean azimuth and its mean aO • The closed contour is the graph of aO versus azimuth from the SASS-1 table, for the scatterom­eter wind speed given in table 3. The individual squares in figure 20 each represent about 6 sec of data (six 0.5-sec integrations at 50-percent duty cycle for each polarization), taken at one azimuth. The 6-sec interval is far less than the equiva­lent anemometer averaging time recommended by Pierson (1983) for a spot observation of any wind-related quantity (such as 00). This explains the data scatter in the individual measurements of aO (the squares) about the SASS-1 prediction of aO

(the closed contour). However, each vector solution (represented by one polar plot), comprised of measurements at 8 to 20 azimuths, required up to 2 minutes of data. This duration at least approaches the several minutes recommended by Pierson. How­ever, to obtain measurements at 8 to 20 azimuths, a strip of ocean surface 3 to 8 n.mi. long must be sampled (see appendix A). Over that distance in a hurricane, much variability can be expected, especially along a radial. Even for synoptic-scale winds, Pierson calculates an expected standard deviation of 1 to 2 m/sec in scatterometer-measured winds for a 10-km sampling cell. Partitioned aO data for the other passes which yielded nominally rain-free data are given in figures 21 to 27.

Figure 28 presents the 34 scatterometer solutions in comparison with radiometer rain rate and INS wind speeds. These plots show that the difference in INS wind speeds at the two August 8 flight levels is not a strong function of rain rate (fig. 28(a», that the difference between wind speeds from the C-130 INS and from the scatterometer is not a discernible function of distance from the storm center (fig. 28(c», and that the C-130 INS and scatterometer measurements compare well for both wind direction (fig. 28(b» and wind speed (fig. 28(d».

Values of measured aO are plotted against C-130 INS flight-level wind speed in figure 29, for e = 19°. Each of the six panels of the figure is for a given range of X, within the 30° window, where X is the horizontal angle between the wind direction and the scatterometer antenna beam. The solid line is aO from the SASS-1 geophysical algorithm. Figures 30 and 31 display similar information for 6 = 39° and 52°, respectively.

Elevation scans.- Mode 3 (elevation scan) data are sometimes used for absolute bias determination of the scatterometer and to gather data to further refine the geophysical algorithm. Numerous elevation scans were obtained during Hurricane Allen, and aO from an example scan is given in figure 32. For Hurricane Allen, absolute bias in the scatterometer instrument was determined through laboratory measurement of waveguide losses and a calibration in which precision spheres were used as targets.

6.4 Geophysical Comparisons

Wind vector and rain rate results from the microwave instruments are presented with the INS and rain radar measurements on a pass-by-pass basis in figures 33 to 58. Each figure contains (at the upper left) information needed to locate the flight tracks with respect to the storm center. The upper right panel shows the profiles of radiometer brightness temperature at as many frequencies as were available. Beneath

1 2

the brightness temperature data is the profile of radiometric wind speed, and in the bottom right panel is the profile of radiometer rain rate. INS wind speeds from both aircraft are shown in the wind speed panel, and profiles from the rain radar compos­ites, whenever they exist, are given in the rain rate graph at the bottom right. Beneath the flight track diagrams on the left is a scatter diagram comparing the radiometric wind speed with the C-130 INS flight-level wind speed (20 to 40 n.mi. from the storm center on August 5; 10 to 40 n.mi. on August 8). Below that, at the lower left, is the INS flight-level wind direction information from each aircraft.

In a'multi-aircraft experiment, the surface winds beneath a higher altitude aircraft, if not measured directly, are normally inferred from the lower altitude INS flight-level winds. This is acceptable provided that the aircraft remain within or not far above the planetary boundary layer. These conditions were not met in the case of the flights through Hurricane Allen. However, the INS winds at the two flight levels were found to be comparable (figs. 10, 11, and 12), at least from the radius of maximum winds to 40 n.mi. from the storm center. Therefore, the decision was made to compare the microwave-derived surface wind speed estimates with the INS winds from 3000 m, in order to eliminate the aircraft collocation problem. To use the 1500-m winds would have degraded the comparison because of nonregistration of aircraft tracks and passage times and gusting.

The 34 scatterometer solutions from mode 2 calculations are shown in figures 33 to 58 for passes where they apply. Each of the solutions appears as'a square. Scatterometer-derived wind speeds are shown in the wind speed profile and in the scatter diagram. Wind directions from these same calculations are displayed in the lower left, with INS wind direction profiles from both aircraft. In some instances, especially near the storm center, the INS wind direction varied too erratically to be displayed.

7. DISCUSSION OF RESULTS

The conclusions, detailed below, are (1) that the measured INS winds at all available flight levels up to 3000 m are very similar, (2) that the radiometer has produced the first available radiometric measurements of wind speeds up to 70 m/sec, while (3) simultaneously measuring rain rates up to 60 mm/hr, and (4) the scatterom­eter is skillful at determining sea-surface wind vector at wind speeds up to 28 m/sec and has provided the beginning of a data set that may be used to improve current scatterometer geophysical algorithms for higher wind speeds.

7.1 Use of 3000-m INS Winds as Estimator for Sea-Level Winds

The INS wind speed measurements do not reveal any large variation due to alti­tude, at least between the radius of maximum winds (20 n.mi. on August 5; 9 n.mi. on August 8) and 40 n.mi. from the storm center. This is apparent not only from the comparison of pass-ordered P-3 and C-130 wind profiles (figs. 33 to 58), but also from the collected profiles and resulting scatter plots for each flight day (figs. 10 to 12). Vertical similarity inside the eyewall does not prevail, probably because of the pronounced slant of the eyewall (30 0 relative to the horizontal on August 5 and 45 0 on August 8, according to Jorgensen (1984». For radial distances greater than 50 n.mi. the similarity is decreased, probably because beyond that distance the vertical motions in the hurricane are insufficient to overcome the atmosphere's usual vertical shear structure.

13

The similarity, however, between the 1500-m and the 3000-m INS winds is obvious between the radius of maximum winds and 40 n.mi. from the storm center. Also, the limited INS data set obtained at 500 m (fig. 12) leads to the same conclusion. Thus, any planetary boundary layer model that acts upon the winds from any of the three flight levels could be used with winds from either 1500-m or 3000-m flight-level measurements.

7.2 Radiometer Wind Speed

The radiometer wind speeds are compared with those from the 3000-m INS for 12 passes on August 5 (fig. 19(c», 14 on August 8 (fig. 19(d», and for each pass (figs. 33 to 58). The range of speeds is 35 to 70 m/sec on August 5 and 20 to 65 m/sec on August 8. Some quadrant dependence is noted on August 5 (the radiometer measurement is too low on the north passes and too high on the south passes). The radiometer may be responding differently in the north and south quadrants, or the boundary layer coupling from sea level to flight level may depend on quadrant. That this is not observed on August 8 may be due to the storm being much more tightly organized on that day.

Aside from this quadrant dependence on August 5, the radiometer wind speeds correspond very closely to those from the 3000-m INS. It was shown in section 6.3.1 how the radiometer brightness temperatures were regressed on INS wind speed over a selected portion of the data from August 8. Then the resulting algorithm was applied to all the data for both days. The good agreement between radiometer and INS over such a large range of wind speeds depends on the use of data at two microwave fre­quencies rather than at one, which also enables the measurement of rain rate. This is important, since heavy precipitation so frequently accompanies high winds.

This success of the radiometer in measuring wind speeds up to 70 m/sec in Hurricane Allen marks the highest known wind speeds measured by any microwave radiometer to date.

7.3 Radiometer Rain Rate

The simultaneous measurement of brightness temperature at more than one fre­quency yields an estimate of the amount of liquid water in the atmospheric column beneath the aircraft carrying the radiometer. The best available comparison data set is that from the 360 0 lower fuselage radar on the P-3 aircraft (see section 6.2.2 and fig. 2).

The P-3 rain radar profiles for passes 1 to 6 and 13 to 25 are shown superim­posed on those from the radiometer in figures 33 to 58. The results agree qualita­tively; that is, the two measurements generally agree in detecting areas of no, low, and high rainfall. Lack of better quantitative agreement is due partly to the uncer­tainties inherent in both measurement systems, but partly to the limitations imposed by comparing the nearly instantaneous radiometer measurement with the time-composite constructions of the rain radar data. One possible source of error is the liquid water content of the air between the two airplanes. Each composite was built from data obtained over approximately six aircraft passes.

It is obvious from figures 33 to 58 that the radiometer is useful for detecting such meteorologically important areas as the rain-free storm center, the eyewall, and the inner and outer rain bands.

14

7.4 Scatterometer Wind vector

Scatterometer-derived values of surface wind speed and wind direction are com­pared with flight-level INS values obtained at 3000 m. (It was concluded earlier that the INS measurements from 3000 m are as satisfactory as those from lower altitudes for use as a surface comparison data set.)

Figure 28(d) reveals that the scatterometer compares very well with the INS for wind speeds up to about 27 m/sec, but that its wind speed predictions are too low for greater wind speeds. The following explanations for this were investigated: (1) in­correct SASS-1 algorithm, from which the aO values were converted to wind vector, (2) instrument bias resulting in incorrect aO , or (3) invalid assumptions regarding the degree of coupling between the surface winds and those at altitude. Included in the first is the possibility of decreased sensitivity of aO at very high wind speeds, which is not modeled in the SASS-1 geophysical algorithm. It must be remem­bered, however, that the SASS-1 algorithm is based on Seasat and aircraft data ob­tained before Hurricane Allen and is limited to about 30 m/sec (Jones et ale 1982). Seasat did not provide high-wind-speed data to improve the SASS-1 algorithm, because a typical resolution cell was not small enough to separate the occasional high-wind rain-free areas from surrounding regions of low winds and/or heavy precipitation. The scatterometer was able to do this during Hurricane Allen. The resulting compari­son with the flight-level INS does leave unresolved the question of aO sensitivity at high wind speeds.

The second possiblity, scatterometer instrument bias, was the subject of an exhaustive study at the NASA Langley Research Center, wherein an absolute bias of -1.1 dB was found through a precision target-sphere calibration. Correction for this bias was applied to all Hurricane Allen data, and thus instrument bias was eliminated as a source of wind speed error.

The third possiblity for disagreement between the scatterometer-derived surface wind speeds and those from the INS at altitude is boundarY,layer dependence. Since the frictional boundary layer of Hurricane Allen has not been specified to the extent that surface wind speeds can be defined, the INS measurements remain the best estimator.

The wind direction comparison between the scatterometer and the 3000-m INS (fig. 28(b» suggests a 12° difference. This is to be expected from the surface friction of a cyclonic boundary layer (Perry and Walker, 1977, p. 66), and does not depend on quadrant.

Within the limitations imposed by insufficient knowledge of the surface winds, the scatterometer results from Hurricane Allen may be useful for verifying or modi­fying the geophysical algorithm. A greater number of unique azimuths were available for each wind vector solution (figs. 20 to 27) for the scatterometer in Hurricane Allen than were available from the Seasat scatterometer experience; thus the wind speed and direction accuracy can be defined better.

The scatterometer is consistent in estimating wind direction. Note in particu­lar scatterometer solutions 13 to 18, all obtained during pass 20E (fig. 23). All three incidence angles (19°, 39°, and 52°) are used, yet the wind direction for each case is 173° ± 6°. The same degree of , consistency is seen for passes 21E and 24S (figs. 24 and 26), both of which used more than one incidence angle.

15

8. CONCLUSIONS

This report has summarized the NASA Langley Research Center analysis of the air­borne microwave remote sensing measurements obtained in Hurricane Allen. Radiometer wind speed was calculated from the increase in antenna brightness temperature over an estimated no-wind value, and radiometer rain rate was calculated from a corrected difference between antenna temperature increases at two frequencies. These data show that the stepped frequency microwave radiometer can simultaneously measure wind speed up to 70 m/sec and rain rate in excess of 60 mm/hr. scatterometer wind vector was obtained from the sea-surface radar cross section measured at various azimuths.

The evaluation of each of the microwave instruments requires qualification for one or more conditions of the experiment. In the case of the radiometer rain rate verification, the failure of underwing droplet samplers degraded the calculation of in situ precipitation from the aircraft rain radars. Assessment of the scatterometer measurement of sea-surface radar cross section in high wind speed was influenced by the fact that the greatest surface wind speeds in a hurricane are generally in or near heavy rain, which attenuated the scatterometer signal. Correction for this attenuation using the radiometer-determined rain rates was not attempted in this analysis. However, the nonavailability of in situ surface wind measurements is the most serious limitation on the evaluation of wind speed results from either microwave instrument.

In this analysis, some light has been shed on the use of active and passive microwave sensors for measuring (from a safe altitude) the near-surface phenomena of interest to hurricane scientists.

NASA Langley Research Center Hampton, VA 23665-5225 June 5, 1985

16

9. REFERENCES

Black, peter G.; and Schricker, Terry 1978: Direct and Remote Sensing of Ocean Temperature From an Aircraft. Fourth Symposium on Meterological Observations and Instrumentation of the American Meteorological Soc., pp. 158-165.

Dome, George 1975: Effect of Precipitation on Choice of Frequency for SEASAT Scatterometer. NASA CR-132749.

Frey, Gary F. 1980: The Hurricane Hunters. J. American Aviat. Hist. Soc., vol. 25, no. 1, Spring, pp. 45-56.

Gloersen, Per; and Barath, Frank T. 1977: A Scanning Multichannel Microwave Radiom­eter for Nimbus-G and SeaSat-A. IEEE J. Oceanic Eng., vol. OE-2, no. 2, Apr., pp. 172-178.

Harrington, Richard F. 1980: The Development of a Stepped Frequency Microwave Radiometer and Its Application to Remote Sensing of the Earth. NASA TM-81847.

Haydu, Kenneth J.; and Darby, Evan R. 1983: Description and Operating Procedures for the NOAA-C130 AWRS System. NOAA TM-ERL RFC-11, U.S. Dep. Commerce, Mar. (Available from NTIS as PB83 197 053.)

Jones, W. Linwood; Black, Peter G.; Delnore, Victor E.; and Swift, Calvin T. 1981: Airborne Microwave Remote-Sensing Measurements of Hurricane Allen. science, vol. 214, no. 4518, Oct. 16, pp. 274-280.

Jones, W. Linwood; and Schroeder, L. C. 1978: Radar Backscatter From the Ocean: Dependence on Surface Friction Velocity. Boundary-Layer Meteorol., vol. 13, nos. 1, 2, 3, 4, Jan., pp. 133-149.

Jones, W. Linwood; Schroeder, Lyle C.; Boggs, Dale H.; Bracalente, Emedio M.; Brown, Robert A.; Dome, George J.; Pierson, Willard J.; and Wentz, Frank J. 1982: The Seasat-A Satellite Scatterometer: The Geophysical Evaluation of Remotely Sensed Wind Vectors Over the Ocean. J. Geophys. Res., vol. 87, no. C5, Apr. 30, pp. 3297-3317.

Jorgensen, David P. 1984: Mesoscale and Convective-Scale Characteristics of Mature Hurricanes. Part I: General Observations by Research Aircraft. J. Atmos. Sci., vol. 41, no. 8, Apr. 15, pp. 1268-1285.

Jorgensen, David P.; and Willis, Paul T. 1982: A Z-R Relationship for Hurricanes. J. Appl. Meteorol., vol. 21, no. 3, Mar., pp. 356-366.

Kaupp, Verne H.; and Holtzman, Julian C. 1979: Hurricane Ava: Anomalous Data Correction. vol. GE-17, no. 1, Jan., pp. 6-13.

Skylab Scatterometer Measurements of IEEE Trans. Geosci. Electron.,

Kidder, Stanley Q.i Gray, William M.; and Vonder Haar, Thomas H. 1980: Tropical Cyclone outer Surface Winds Derived From Satellite Microwave Sounder Data. Mon. weather Rev., vol. 108, no. 2, ~eb., pp. 144-152.

Lawrence, Miles B.; and Pelissier, Joseph M. 1981: Atlantic Hurricane Season of 1980. Mon. Weather Rev., vol. 109, no. 7, July, pp. 1567-1582.

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Marks, Frank D., Jr. 1981: Evolution of the Structure of precipitating Convection in Hurricane Allen. 20th Conference - Radar Meteorology, American Meteorol. Soc., pp. 720-725.

Merceret, Francis J.; and Davis, Harlan W. 1981: The Determination of Navigational and Meteorological Variables Measured by NOAA/RFC WP3D Aircraft. NOAA TM-ERL RFC-7, U.S. Dep. Commerce, Apr. (Available from NTIS as PB81 225 468.)

Moore, R. K.; Birrer, I. J.; Bracalente, E. M.; Dome, G. J.i and Wentz, F. J. 1982: Evaluation of Atmospheric Attenuation From SMMR Brightness Temperature for the SEASAT Satellite Scatterometer. J. Geophys. Res., vol. 87, no. C5, Apr. 30, pp. 3337-3354.

Perry, A. H.; and Walker, J. M. 1977: The Ocean-Atmosphere System. Longman Inc.

Pierson, Willard J., Jr. 1983: The Measurement of the Synoptic Scale Wind Over the Ocean. J. Geophys. Res., vol. 88, no. C3, Feb. 28, pp. 1683-1708.

Rogers, R. R. 1976: Statistical Rainstorm Models: Their Theoretical and Physical Foundations. IEEE Trans. Antennas & Propag., vol. AP-24, no. 4, July, pp. 547-566.

Ross, D.; AU, B.; Brown, W.; and McFadden, J. 1974: A Remote Sensing Study of Pacific Hurricane Ava. proceedings of the Ninth International Symposium on Remote Sensing of Environment, Volume I, Willow Run Labs., Environmental Res. Inst. of Michigan, pp. 163-180.

Schroeder, Lyle C.; Boggs, Dale H.; Dome, George; Halberstam, Isadore M.; Jones, W. Linwood; Pierson, Willard J.; and Wentz, Frank J. 1982: The Relationship Between Wind Vector and Normalized Radar Cross Section Used To Derive SEAS AT-A Satellite Scatterometer Winds. J. Geophys. Res., vol. 87, no. C5, Apr. 30, pp. 3318-3336.

Thompson, T. W.; Weissman, D. E.; and Gonzalez, F. I. 1983: L Band Radar Backscatter Dependence Upon Surface Wind Stress: A Summary of New SEASAT-1 and Aircraft Observations. J. Geophys. Res., vol. 88, no. C3, Feb. 28, pp. 1727-1735.

Weissman, David E.; King, David B.; and Thompson, Thomas W. 1979: Relationship Between Hurricane Surface Winds and L-Band Radar Backscatter From the Sea Surface. J. Appl. Meteorol., vol. 18, no. 8, Aug., pp. 1023-1034.

Willoughby, H. E.; Clos, J. A.; and Shoreibah, M. G. 1982: Concentric Eye Walls, Secondary Wind Maxima, and the Evolution of the Hurricane Vortex. J. Atmos. Sci., vol. 39, no. 2, Feb., pp. 395-411.

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TABLE 1.- AIRCRAFT PASSES

[Times are Greenwich Mean Times given in hours, minutes, and seconds]

C-130 P-3 Storm center

Pass Start, Stop, Start, stop, Alt. , Lat. N, Long. W, Time,

hr min sec hr min sec hr min sec hr min sec m deg min deg min hr min

August 5

1N 11 33 50 11 44 24 11 30 14 11 42 43 1500 15°56' 70°20' 11 37 2S 11 44 38 12 04 34 11 42 58 11 57 36 1500 15°56' 70°25' 11 52 3W 12 38 10 12 46 48 12 24 58 12 36 00 1500 15°59' 70°38' 12 35 4E 12 47 02 13 07 55 12 36 14 12 52 48 1500 16°01' 70°43' 12 51 5S 13 30 58 13 46 05 13 03 22 13 15 22 500 16°04' 70°54' 13 24 6N 13 46 19 14 01. 55 13 15 36 13 39 36 500 16°05' 70°57' 13 38 7N 15 03 22 15 14 53 14 42 58 14 59 31 1500 16°15' 71°22' 14 58 8S 15 15 07 15 29 46 16 09 50 16 31 12 500-1500 16°22' 71°39' 15 53 9S 15 30 00 15 46 48 16 35 02 16 54 00 1500 16°24' 71°45' 16 12

10N 15 47 02 15 57 50 16 54 14 17 06 43 1500 16°26' 71°50' 16 26 11N 15 58 05 16 09 22 17 20 10 17 29 17 1500 16°28' 71°56' 16 43 12S 16 09 36 16 15 36 17 29 31 17 50 24 1500 16°30' 72°01' 16 59

August 8

13E 18 50 .10 19 34 00 18 30 29 18 58 48 1500 24°09' 92°00' 19 02 14W 19 20 38 19 38 24 18 59 02 19 13 55 1500 24°11' 92°05' 19 18 15W 19 38 38 19 54 14 19 14 10 19 28 34 1500 24°12' 92°09' 19 34 16S 19 57 07 20 14 10 19 28 48 19 43 55 1500 24°13' 92°13' 19 51 17S 20 14 24 20 31 41 19 44 10 20 00 00 1500 24°14' 92°17' 20 07 18N 20 31 55 20 48 43 20 00 14 20 17 31 1500 24°15' 92°21' 20 24 19N 20 48 58 21 05 17 20 17 46 20 34 05 1500 24°16' 92°25'. 20 41 20E 21 05 31 21 30 43 20 34 19 20 56 10 1500 24°17' 92°29' 21 02 21E 21 30 58 21 55 41 20 56 24 21 17 46 1500 24°19' 92°34' 21 26 22W 21 55 55 22 16 19 21 18 00 21 19 41 1500 24°20' 92°38' 21 47 23W 22 16 34 22 36 29 21 50 10 22 02 53 1500 24°21' 92°42' 22 13 24S 22 36 43 23 00 14 22 03 07 22 19 12 1500 24°22' 92°45' 22 31 25S 23 00 29 23 21 07 22 19 26 22 34 34 1500 24°23' 92°47' 22 50 26N 23 21 22 23 30 00 22 34 48 22 56 24 1500 24°24' 92°48' 23 02

19

TABLE 2.- MODE DEFINITIONS FOR SCATTEROMETER DURING HURRICANE ALLEN

Mode Antenna azimuth Antenna elevation (with respect to aircraft nose) (with respect to nadir)

Mode 2 15° to 345° in 30° Any fixed elevation; (Azimuth scan) increments usually 19°, 39°, or 52°

Mode 3 Any fixed azimuth 0° to 60° in 5°, 6°, (Elevation scan) or 10° increments

Mode 8 Any fixed azimuth Any fixed elevation (Fixed position)

20

TABLE 3.- SCATTEROMETER SOLUTIONS

[ Sol. T Start Stop

Dist. from Radiometer I Radiometer INS Sca tterome ter INS Sca tterome ter I N I f I Nominal:1 Probe of storm wind wind wind

. _ No. o. No. 0 .. _ _. _ rain I wind . w~na I of of 300 I 0.5-sec I~nc~aencelsei~c~ea pass\ GMT, GMT,

center, rate, speed, speed, speed, direct., no. hr min sec hr min sec d~rect., 1. . . angle all.as

n=mi= mm,lhr m/sec m/sec m/sec deg d a ~ases sectors ~ntegrat~ons d' , eg eg %

1 13E 19 06 15 19 07 12 47.4 0.6 28.0 24.9 24.1 200 190 2 9 79 39 72 2 13E 19 07 27 19 08 38 42.6 .6 27.7 25.2 24.1 200 185 2 8 87 39 46 3 13E 19 08 39 19 09 50 38.6 .6 29.6 24.9 23.0 198 195 2 10 98 39 91 4 13E 19 09 51 19 11 02 34.2 0 29.0 26.2 26.0 202 189 2 6 70 39 16 5 13E 19 11 03 19 12 14 30.4 1.0 29.4 27.4 26.6 205 196 2 7 93 39 98 6 14W 19 31 13 19 31 55 34.6 0 33.3 27.4 28.0 031 024 3 6 47 39 84 7 16S 20 12 01 20 13 12 58.4 1.6 20.1 17.6 19.5 291 283 2 10 81 39 54 8 17S 20 17 03 20 18 14 50.1 1.2 15.4 11.4 19.4 286 264 2 11 95 39 79 9 17S 20 18 59 20 20 10 43.6 1 .1 13.9 18.7 19.9 285 282 2 6 67 39 53

10 17S 20 20 11 20 20 53 40.3 1.0 18.2 17.9 21.0 288 280 2 6 55 39 33 11 17S 20 21 07 20 22 19 35.8 .9 16.1 19.9 20.9 294 279 2 11 84 39 30 12 17S 20 22 20 20 23 31 31.2 .9 20.6 22.6 21.9 293 264 2 11 91 39 31 13 20E 21 14 39 20 14 46 32.0 0 28.9 29.2 24.6 194 176 2 6 84 52 53 14 20E 21 15 51 21 17 02 35.9 .2 28.3 28.8 22.6 189 166 2 6 101 52 65 15 20E 21 17 03 21 18 14 40.5 1.0 28.9 27.7 23.5 188 166 2 8 103 52 32 16. 20E 21 18 44 21 19 55 46.5 .5 29.7 28.0 27.1 182 172 2 10 93 39 12 17 20E 21 19 56 21 21 07 50.5 .2 31.3 27.3 26.5 182 180 2 10 83 39 22 18 20E 21 21 08 21 22 19 55.6 .1 33.1 27.9 25.5 182 166 2 11 91 19 83 19 21E 21 40 05 21 41 17 50.8 .1 30.5 27.5 27.6 180 154 2 9 92 39 5 20 21E 21 42 29 21 43 41 42.1 .6 29.5 27.? 22.4 188 160 2 10 88 39 95 21 21E 21 43 42 21 44 53 38.8 .2 29.1 26.3 23.5 188 169 2 10 88 39 98 22 21E 21 45 08 21 46 19 33.8 0 29.3 28.0 21.4 193 171 3 6 86 52 8 23 22W 21 55 41 21 56 24 2.6 1.3 25.2 13.4 14.9 026 036 2 7 60 19 95 24 22W 22 06 15 22 07 26 41.4 .8 33.5 25.1 28.6 026 016 2 11 94 39 27 25 22W 22 07 27 22 08 38 45.5 .6 33.9 25.3 28.0 027 008 2 10 82 39 95 26 22W 22 13 27 22 14 38 68.2 .1 32.9 31.5 25.3 032 001 3 8 97 52 33 27 24S 22 49 41 22 50 53 41.7 .2 26.6 23.7 23.9 269 264 2 9 100 39 45 28 24S 22 50 54 22 51 50 45.9 0 28.6 23.8 23.6 271 267 2 9 79 39 45 29 24S 22 52 34 22 53 46 51.6 .1 27.9 24.2 23.5 275 266 2 9 99 19 67 30 24S 22 53 47 22 54 43 55.6 .2 27.8 24.8 23.2 272 265 2 7 69 19

I 46

31 25S 23 02 24 23 03 36 65.6 0 29.5 23.6 25.5 284 273 2 11 85 39 58 32 25S 23 03 37 23 04 19 62.0 0 29.7 24.4 25.2

I 282 l 276

I 2

I 6

I 61

I 39

I 66

33 26N 23 30 I 44 23 31 55 35.7 .9 28.9 34.7 28.2 114 100 2 8 75 39 71 34 26N 23 31 56 23 33 07 39.6 .9 31.8 33.6 27.6 115 082 2 8 98 39 13

~

Figure 1.- NOAA C-130 aircraft en route to Hurricane Allen, August 4, 1980.

22

tv W

E

" OJ "0 ~ +-' 0..-+-' r--c::C

5000

3000

1500

500 r

Tail radar (rain) 360 0 scan

fuselage radar (rain)

360 0 scan

~ l\ --~~ - -_ .. - ---" 1-""1 Sea surface o -~ __ .- ..... -:-~ ----. --"" ---------.. ~ ~ :.;::

Figure 2.- Vertical stacking of NOAA aircraft in Hurricane Allen on August 5 and 8, 1980, showing NOAA rain radars and NASA microwave instruments.

11 12 13 14 15 16 17 18 19 GMT, hr

(a) August 5.

3000 C-130

E", 2000 ..c

1000

OL-__ ~ __ -L __ ~ ____ ~ __ ~ __ ~ __ ~ ____ ~~

10 11 12 13 14 15 16 17 18 19

GMT, hr

(b) August 8.

Figure 3.- Time histories of C-130 and P-3 altitude during storm penetrations.

24

100

80

°E 60 c ~.!' 40 Q) ...... c: Q)

u 20 E L-. e

0 .-VI --e .c -20 ...... L-. e c: Q) -40 u c: .~ VI

Cl -60

-80

-100 -100 -80 -60 -40 -20 0 20 40 60 80 100

Distance east of storm center, n. mi.

(a) C-130.

100

80

E 60 C ..: 40 Q) ....... c: Q) 20 u E :l-e 0 ....... VI "-e .c -20 ...... :l-e c

'-40 Q)

u c J:9 ··60 VI

Cl

-80

-100 -100 -80 -60 -40 -20 0 20 40 60 80 100

Distance east of storm center, n. mi.

(b) P-3.

Figure 4.- Aircraft flight paths with reSpE!ct to the storm's moving center on August 5.,

25

26

100

80

'E 60 c ~ 40 Q) ...-c Q) u 20 E I-0 ....... 0 VI ...... 0

..c: -20 ...-I-0 C Q) -40 u c .l9 VI -60

0

-80

-100 -100 -80 -60 -40 -20 0 20 40 60 80 100

Distance east of storm center, n. mi.

(a) C-130.

100

80

E 60 C 1-'" Q)

40 ...-c: Q)

20 u E I-0

0 ...... VI ...... 0

..c: -20 ....... I-0 C Q) -40 u c: co ........

-60 .~ 0

-80

-100 -100 -80 -60 -40 -20 0 20 40 60 80 100

Distance east of storm center, n. mi.

(b) P-3.

Figure 5.- Aircraft flight paths with respect to the storm's moving center on August 8.

tv -...J

Figure 6.- Hurricane Allen track on August 4-10, 1980, showing locations of aircraft interceptions.

28

Distance south of storm center, n. mi.

240r-----.------,-----,-~--_,_---__,

220

200

~

~ 180

E .!!l

~ 160 :c .~ 00

140

120

A

60 Distance south of storm center, n. mi.

Distance south of storm center, n. mi.

(a) Wind speed.

Figure 7.- Relationship between measured brightness temperature and calculated wind speed and rain rate for various features of Hurricane Allen.

-40 -20 20 Distance south of storm center, n. mL

40

Flight track

60

240.-----.------.------.-----.------,

E :;:,

220

200

~ 180

E .l!l

~ 160

~ co

140

120

A

Distance south of storm center, n. mL

60.--------.-------.--------.-------~------~

A

50

~ 40 E

Distance south of storm center, n. mL

(b) Rain rate.

Figure 7.- Concluded.

29

w o

Radiometer operation

1 frequency

2 frequencies

4 frequencies

Wind & rain solutions

5catterometer operation

Mode 2

Mode 3

Mode 8

5torm track equation

C-13O

P-3

Pass/transit designation

C-13O

P-3

1000 Hoo

IN 25 Tl 3W 4E T2

IN 25 Tl 3W 4E T2 55

1200 1300

55

6N

6N T3

T3 T4

1400

GMT

T4 T5

T5

T6 7N 85 95 ION 11 N 125

7N T6 T7 T8 T9 85 TlO 95 ION TllllW 12E

1500 1600 1700

Figure 8.- Bar graph showing instrument status and pass number designations for August 5.

I

.

1800

w

Radiometer operatIOn

1 frequency

2 frequencies

4 frequencies

Wind & rain solutIOns

5catterometer operation

Mode 2

Mode 3

Mode 8

Wind vector solutIOn number

5torm track equation

C-13O

P-3

Pass/translt designation

C-13O

P-3

I

i

BE

1630 1700 1800

I

I I

1-5 6 7 8-12 13-18

BE 14 W 15W Tl 165 175 18N 19N 20E

14 W 15 W 165 17 5 18N 19N 20E 12lE 22W

1900 2000 2100

GMT

I I

I 19-22 23 24-26 28-30 31 32 33 34

2lE 22W 23W 245 255 26N

Tl 23W 245 255 26N T2 T3

2200 2300

F1gure 9.- Bar graph showing instrument status and pass number des1gnations for August 8.

I I

I

I I

I

I

I

2400 0030

100 100

90 90

80 80

e: 70

E af 60

~

e: 70 E af ~ = "0 " c= 50 i i <ii

'" ~ 40 '"

E '" go

c= .l!l

.l!l V>

V> 30 z

z

20

10 10

0 100 o 100

Distance from storm center n ml Distance from storm center, n ml

(a) P-3. (b) C-130.

100 100

90 90

80 80

0 70 (() 70

E u e!

c=

I 60

= 50 "

«D8 E 60

af 0 ~ 0 -g 50

i i V> V>

~ 40

~ ~ 40

0 ~ '-'

30 0 '-'

30

20 0

10

0 10 100 100

P-3 INS wind speed, mlsec P-3 INS wind speed, mlsec

(c) P-3 vs. C-130 1ns1de the eyewall. (d) P-3 vs. C-130 outs1de the eyewall.

F1gure 10.- INS w1nd speeds corrected for forward mot1on of storm for August 5. P-3 at h = 1500 m.

32

100 100

90 90

80 80

~ 70 E ~

70

E

l 60 I 60

"C C

i 50 "C c: 50 i

'" ~ 40 g' .l9

'" ~ 40 '" c: .l!I

Vl z 30

Vl

~ 30 ,

"-0

'" 20 , 20

u

10 10

0 100 0 100

Distance from storm center, n ml Distance from storm center, n ml

(a) P-3. (b) C-130.

100 100

90 90

80 80 0

0 70 00 70

~ @00 ~ 0

E E 0 60 0 0 60

I 0 00 I

"C 50 "C C c: i 0 i Vl Vl

~ 40 ~ :;;;: ~ u

30 U

20

10

o 100 100

P-3 I NS wind speed, mlsec P-3 INS wind speed, mlsec

(c) P-3 vs. C-130 1ns1de the eyewall. (d) P-3 vs. C-130 outside the eyewall.

F1gure 11.- INS w1nd speeds corrected for forward mot10n of storm for August 8. P-3 at h = 1500 m.

33

100 100

90 90

80 80

~ 70

E

I 60

~ 70

E

I "C

~ 50 ~

c: ~

'" '" "E 40 '" g'

.!!l

"E g;, c: .!!l V>

V> 30 z z

20

10

100 100

Distance from storm center, n ml Distance from storm center, n ml

(a) P-3. (b) C-130.

100 100

90 90

80 80

70 70

~ ~ E E

J 60

J 60 0

"C 50 0 ~ 50 c: ~ 0 ~

~o V> o 08 V> z z

40 @ COo ~

40 O@ ~ o CD

~fX) u 0 OG> u 30 30

~Oo

20 20

10 10

100 100

p-3 I NS WI nd speed, mlsec P-3 INS Wind speed, mlsec

(c) P-3 Vs. C-130 ins~de the eyewall. (d) P-3 vs. C-130 outside the eyewall.

F~gure 12.- INS w~nd speeds corrected for forward mot10n of storm for August 5. P-3 at h = 500 m.

34

,----------.----------~M

•

., In m!

80

00

80 0 0

2n ml ~------------------~~80

40

8O~----------------~~~

80

80

..

00

o c9

0 0

o o

00

+1 n ml

+2n ml

o 0

"')n ml

c no INS Wind speed mlsllt

M

80

80

(a) Inside the eyewall.

,----------,----------,80 00

.,

.. 3n ml

80

0 0 II

\9

"

2n nil ~----------------~~~80

..

.,

• I n m. OJ

'" 0

~ 0

.,

80

..

+In ml

c no IN5lrindSIHd, mlsec

(b) Outside the eyewall.

F1gure 13.- C-130 INS wind speed plotted against itself for along-track shifts of -3 to +3 n.mi. Pass 1N.

35

36

.-----------.-----------.~

o 00

., M~--------__ ---------~)~O~m~'

"

4IJ

..

00

o o

o o

o 0

2n ml ~----------------'-'--71 ~

o o

1 n ml

+ I n ml

~--------------------~M

o

o 00

o 0

00

+2n ml

00 0

• In ml

'" C UJINSwlndspeed mlSK

(a) Inside the eyewall.

"

M~------------------~

.,

2n ml

~--------------------~M

..

In ml ~~--------------------~

40

+ I n ml

~------------------~M

40

+Zn rnl

'"

+ 1n ml

C IJ)INS Wind speed mlsec

(b) OutsLde the eyewall.

FLgure 14.- C-130 INS wLnd speed plotted against Ltself for along-track shifts of -3 to +3 n.mi. Pass 2S.

~

.c E E

.$ E c ~ ~ ~

16 '"

60r---.---,---.----r---.---.---.---,

50

40

30

60

50

40

30

20

10

August 5 1116 - 1422 GMT

August 8 1916 - 2151 GMT

60 70 80 o

Distance from storm center, n ml

August 5 1537 - 1875 GMT

August 8 2054 - 2306 GMT

70 80

F1gure 15.- Rain radar profiles accumulated over 3600 azimuth.

37

.<: E E

~ c ~ ~ ~

16 '"

38

60r---r---,---,----,---r---,---,---,

50

40 All m uths 3050 to 3250 AZimuths 3500

to 0100

30

20

10

60

50

40 AZimuths 2600 to 2800 AZimuths OBO

o to 100

0

30

20 -

60,..-----,----,----,----,,-----,----r---,----,

50

40 AZimuths 17(f to 1cxf AZimuths 1250 to 141'

30

20

80

Distance from storm center, n ml

F1gure 16.- Rain radar prof1les for August 5, accumulated over azimuth sectors 1nd1cated.

~

~ E

'" E c E

"' "C

"' '"

60

50

40 AZimuths 28t> to 3020 AZimuths 0150 \0 0350

30

20

10

0

60

50

40 AZimuths 1900 to 2100 AZimuths 1020 \0 12t>

30

20

10

0

Olstance from storm center, n ml

F1gure 17.- Ra1n radar prof1les for August 8, accumulated over aZ1muth sectors 1nd1cated.

39

><

c( .....

><

,,£ ;....

180

170

160 Regime H

150 Regime L

140

130

120

110 0 10 20 30 40

C-I30 INS wind speed, m/sec

(a) C-130 INS w~nd speed vs. measured br~ghtness temperature, at 10 to 50 n.m~. from the storm center.

180

170 ~

160 f-

150 ~

140 f-

130 -0

~ 120 ~a3cS~

o 0

110 0

I I I I I 10 20 30 40 50

C-I30 INS wind speed, m/sec

(c) C-130 INS w~nd speed vs. adJusted br~ghtness temperature, reg~me L.

I 60

70

70

70

60

50 ~ E

f 40

"C <:: i

'" 30 ~ 0

~ a<

20

10

70

C -130 I NS wind speed, m/sec

(b) C-130 INS w~nd speed vs. rad~ometer wind speed result~ng from appl~cat~on of regress~on of data ~n (a) for regime H.

70 0

60~

501-

~ E ~ 0

~ 40~ 000

"C

0 <:: 0 i

~

30- 8 0 ~ '" ~

~ r~ 0

~ a<

20 - 00 :OCOOo

Jt fa. °0 10 00 000 0 00

o 0

,.,,~Ol I I I I I 10 20 30 40 50 60

C-I30 INS wind speed, m/sec

(d) C-130 INS w~nd speed vs. radiometer w~nd speed resulting from regress1bn of data ~n (a) for regime L.

70

F~gure 18.- Development of rad~ometer w~nd speed regression for data of August 8.

40

70

60

50

~ E al 40 80

0 ~ "C c: 0 3

I 30 0

0 "C

0 I:! o 00<0 20 o 0

70

C-I30 INS wind speed, m/sec

(a) C-130 INS w1nd speed vs. rad10meter w1nd speed, August 8.

100

90

80

70 ~ E

l 60

"C 50 c: 3

'" " 40 ~ iii '" 30

20

10

0 10 30 40 50 90 100

C-I30 INS Wind speed, m/sec

(c) C-130 INS wind speed vs. rad10meter w1nd speed, August 5 at 20 to 40 n.mi. from storm center.

"" _c( I-

~ E

1 "C c: 3 ~

~ E 0 -5 I:!

180

170

160

150

140

130

110 '--_---''--_--L __ --'-__ -'--__ -'-__ -'-_---'

100

90

80

70

60

50

40

30

20

10

o ro C-I30 INS wind speed, m/sec

(b) C-130 INS w1nd speed vs. adJusted br1ghtness temperature, August 8.

C-I30 INS Wind speed, m/sec

100

(d) C-130 INS wind speed vs. radiometer wind speed, August 8 at 10 to 40 n.m1. from storm center.

F1gure 19.- Results of rad10meter wind speed calculations for reg1mes Hand L.

41

42

270--+----

SolutIOn 3

o

lTO-+----- o

o 195

SolutIon 5

000

180

000

+

180

000

o o

000 Center:; 14dB

-----1-090 270-+---- -----+-090

180

000

-----+-090 270-+----- +

189

180

Center = lAdS

Flgure 20.- Normallzed radar cross sectl0n (ao ) aZlmuth-scan data for pass 13E. See sectl0n 6.3.2 for explanation.

000 Center = ·l4dB

170 090 170-+-- ---+-090

o

180

F1gure 21.- Normalized radar cross section (00 ) aZ1muth-scan data for passes 14W and 16S. See sect10n 6.3.2 for explanation.

43

44

000 000

Solution 8 Center = 16dB Solution 9 Center = 14dB

0

8 0

0 0 INS

0

0 0

270 + 090 110

0

0

lBO 180

000 000 Solution 10 Center = 14dB

INS

170 090 270

lBO

000

Center = 14dB

090

o o

180

F~gure 22.- Normalized radar cross section Cao) az~muth-scan data for pass 17S. See sect~on 6.3.2 for explanat~on.

090

000 000 SolutIOn 13 Center = HidB Center = 16dB

o

Z10--j------ -----+ 09Q 170--1------

INS 180 INS 180

000 000 SolutIon 15

Z10-+------ -----+-09Q 170-+--- ----t-09Q

INS 180

000 000 Solution 17

0 0

c

dJ c

170 + 09Q 170 + c

F1gure 23.- Normal1zed radar cross sect10n (0°) azimuth-scan data for pass 20E. See section 6.3.2 for explanation.

45

270

110

46

Center =-141:18 Center = 14d8

o

090 270 090

INS 180

000 000

0 0

0

0

090 170 + 090

INS 180

Figure 24.- Normalized radar cross section (0°) aZ1muth-scan data for pass 21E. See section 6.3.2 for explanation.

000 000 SolutIon 23

170-+--- oro

170

o

o + ---t-oro 1W-+--------

o

ISO

ISO 000

359

+

o

Center = -}6dB INS

----------+_ oro

F~gure 25.- Normal~zed radar cross sect~on (00 ) az~muth-scan data for pass 22W. See sect~on 6.3.2 for explanation.

47

48

000 000 Solution 27 Center = l~B Solution 28 Center = -l4dS

o o

+ 090

o

000 000 Center = 6dB

+ 090

o

180 180

Figure 26.- Normal~zed radar cross sect~on (0°) az~muth-scan data for pass 24S. See section 6.3.2 for explanation.

090

090

270

000 Solution 31 Center == 14dB Solution 32 Center = -141:18

o 0 o

o INS

+ 090 270 + 090

o

lao 180

000 000 SolutIOn 33 Center = 14dB Solution 34

0 0

0

+ 090 270 + 090

FLgure 27.- Norma11zed radar cross section (ao) azimuth-scan data for passes 25S and 26N. See sect10n 6.3.2 for explanation.

49

25.-------,-------,-------,-------,------,

20

~ 15 E

~ u 10

-10

+ + +

~ +++

+ + + ::! + "++

++. + t ++

.... +. :++ • +: '\.! + + •• +

+ + .t • + ++++

++ 4+:/++

+ + ..

+ +

+ +

++ +

+ +

++

-15 L-______ L-______ L-______ L-______ '--____ ----"

o 10 20 30 50

Radiometer rain rate, mmlhr

(a) Radiometer raLn rate vs. difference between INS wLnd speeds from C-130 and P-3.

I I I I I I

~ 00

E 61- 0 0 lJ..

.:

j 0

0

4r-- 0 -~ T3 V> 0

0 V> 2- 0 -:z

0

:l 0 CD []JQJ

U 0 0

al 0 u

~ 0 0 0

"C 0 c:: 0 i -2- 0 0 0_

!:' 0

Cl 0

E 0

~ -4 r-- -.5

-6 I I I I I I 0 10 20 30 40 50 60 70

Distance from storm center n ml

(C) Distance from storm center vs. dif-ference between C-130 INS WLnd speed and scatterometer wLnd speed.

~Or__,r_------._------_,r_------._------~

~ 270

'" ~ e ~ !;l E 180 ~

s: 090

DOO

-040

o

o o

Wind directIOn from C-13O INS, deg

(b) Scatterometer wind directLon vs. C-130 INS wLnd direction.

45

40

'-' 35

~ al ~ 30

"C '0 00 c:: i ~

00 0 '" 25 0 0; 0 E lID 0 0 e '" o 0 == 0 ~ 0 0 V>

20 lIDO

15 0

C-13O INS wind speed mlsec

(d) Scatterometer wind speed vs. C-130 INS wind speed.

45

FLgure 28.- InterpretatLon of the 34 scatterometer solutions and INS wind speed.

50

4

o

-2 o

x = 75° X = 105° 4

!g 0

'"

-2

0

-4

0

X = 135° X = 165°

-2

10 15 20 25 30 35 40

C-I30 INS wind speed, misec

F1gure 29.- Norma11zed radar cross section vs. C-130 INS w1nd speed for specif1ed values of w1nd aspect angle <X). So11d curve 1S aO from SASS-1 geophysical algorL thm. a = 19°.

51

-4

-6 X = 15° X = 45° B

° ° -8 ° 0 C

° EI ° -10

-12

-14

-4

-6 X = 75° X = 105°

° CD

-8 "C

§D ~{;l 0';

° -10 ~ EI ° []I] 0 0 ° B

c 0 o ° -12

-14

-4

-6 X = 135° iD

-8

~8 B ° ° -10

-12

-14 10 15 20 25 30 35 40 10 20 25 40

C-I30 INS wind speed, mlsec

Fl.gure 30.- Normall.zed radar cross sectl.on vs. C-130 INS wind speed for specl.fied values of wl.nd aspect angle ( X> • Solid curve is (p from SASS-1 geophys 1. cal algorl.thm. 9 = 39°.

52

-4

-6

-8

-10 o

-12

-14

-4

-6

-8 :g

°0 -10

o o -12

-14

-6

-8

-10 o B iI!!

10

C-I30 INS wind speed, mlsec

F1gure 31.- Normalized radar cross section vs. C-130 INS wind speed for specified values of w1nd aspect angle <X). Solid curve is 00 from SASS-1 geophysical algor1thm. e = 52°.

53

54

~ ~

0;

15~----.------.------.------.-----.------.

10

0

-5

-10

-15

-20~-----L----~------~-----L------~----~ o 10 20 30

e, d~ 40 50 60

F1gure 32.- Example elevat10n scan: a O vs. 8. Sol1d 11nes are from SASS-1 geophys1cal algor1thm for the appropr1ate wind aspect angle and INS wind speed ±2 m/s.

E

~ ~ a .c 1: g

~

Au<Just S, 1980 Pass IN

Storm center ISo56'N, 700 20'W 11117 GMTI

80 I I I I I I I I I I I I 140

60 - P 3 C 130 -

~o 1130 GMT r Ih = 15{)O ml

-Ih=26oo-JOOOml

- 120

20 - \ 1IJ4 GMT -

1143 GMT 11M GMT 100

-20 r- - ~

~ 1l.

40 r- - E .., 60 r- -

" I I I I I I I I I I I I 80 -60 40 20 20 40 60 80 -80 -60 -40 20 20 40 60 80

.c

r Distance east of storm center n mt <;

E Q

~ 100

90 120

80 100

~ 0 E 70 100 i" 0

~ 60 g

,jQ:,'b i

~ 50 00

-,; 00 -'" 0

90

80

--- Radiometer

----- P J INS

--- C-1JO INS

o Scatterometer :'l 40 70

i 30 ;;; o Radiometer ~ 60

20 o ScaHerometer al 5{) ~

10 g ~

100

C-1JO INS Wind speed m/,ec

~O'--'---'---'---'---'--,,--'---.---r--' 10

60

270 --- Radiometer

5{) ----- Rain I3dar

40 .c E E

" ~

30 ~ ----- P J INS

" ~ ;;

c ___ ~-....-_~'\. ___ -_/

3: 090 ... ____ .,_1' "\ ...... .,.,....---... ___ ,--' ......

--- C-l3O INS

o Scatterometer

Radial distance from storm center, n mt Radial distance from storm center, n rnl

F1gure 33.- F11ght tracks and results of m1crowave and a1rcraft sensor measurements for pass 1N.

100

55

E

co ~

~ " ~ t: g

co

~

56

August 5, 1980 Pass 25

Storm center 150 56'N, 7O°'25'W 11152 GMTI

80 I I I I I I 240

60 P - 3 C llO -I h = 1500 m I Ih = 2600 lOOO m I

40 - 220

20 -

1143 GMT 20

40

1144 GMT

I -

I -,

~ 200

i! 1< E 180 $

-60 1204 GMT J -co

-80 I I I I I I

80 -80 -60 -40 20 20 40 60 80

~

! Olstance east of storm center, n ml ~

E 2

~ 100

90

80 100

~ E 70 100

i 60 90 --- Radiometer Z! i ----- P 3 INS

~ 50 80 --- C-110 INS ~ ~ 40 70

o Scatterometer

§ lO ~ o Racllometer

5! 60 E

20 o Stan.romet.r i ~ Z!

10 ,.

100

C-IJJ INS wind spea:l, m/sec

J60 10

,/ 60

--.;-- .... _-----'\,,, ,-270 1\...:-;;4~-v---'"'_-./',_j ! 50 I

_I'/'''-, ,

~ " t: " !! II II

S II 40 II

~ 1/ iii 180 .c " E II E E I' co

" 0

~ lO II

~ ----- P 3 INS I' I

" --- C-110 INS co I

Z! ~ I

--- Radiometer

----- Rain /'Idir

;0 0 Scatterometer 20 Il'lO

10

000 0 100

Rachal distance from storm center, n ml Radial distance from storm center, n ml

F~gure 34.- Fl~ght tracks and results of microwave and a~rcraft sensor measurements for pass 28.

100

E

~ ~ '0 ~ t: 2'

c

~ c;

August S, 1980 Pass IN

Storm center 150 59'N, 70°38' tim GMTJ 80

I I I I I I I I I I I I 24Or---,---,---,---,---,---,---,---,---,---,

60 f- P-J C 130 -Ih=l500ml In = 26oo-JOOO m I

40 f- - 220

20 f- -1225 GMT ____

1236 GMT 1238 GMT--- 1241 GMT

-20 f- -

-40 f- -

-60 r- -I I I I I I I I I I I I

80 60 -40 20 20 40 60 80 80 -60 -40 20

DIstance east of storm center. n ml

100

90

80 100

{ 10 100 ,r ~ 60 "2'

90 --- Radiometer

~ ----- P-3 INS

~ 50 80 --- C-IJJ INS

~ "§ 40 10

o Scatterumeter

!t RadIometer ! 0

30 0 Scatterometer ~

iE E 20 i

~

1U "2' ;;

10 80 100

C 130 INS wind speed, m/ sec

360

60

210 ~ 50 ~

--- Radiometer

----- Rain rodar

g sa

40

1ii 180 ~

E E E

c 0

~ JJ -g ----- P-J INS

" --- C-1JJ INS c

"2' ~ ;: 0 Scatterometer 20

090

, 10

"' ... ----I ........ -,'--,"'I'_\I'''\. ....

000 0 10 60 10 80 100

Radial distance from storm center, n ml Rachal distance from storm center, n ml

Flgure 35.- Fllght tracks and results of microwave and alrcraft sensor measurements for pass 3W.

100

57

80

E 60

40 c

i 20

'0 ~

1: 20

g 40

~

c

~ 60

80

58

August 5, 1980 Pass 4E

Storm center 16° 01' N, 70° 43' W Il2S1 GMT!

I I I I I I I I I I I I 240

r- P 3 Ih= ISOOml

C -130 -Ih = 1600 JOOOm I

r- - 120

r- -

1136 GMT --..... _---

r- --1153 GMT

r-

1147 GMT '-''-'-'' -IJtl8 GM~

200 ~ ~

~ :!:. E 180 ..,

r- -c

I I I I I I I I I I I I -60 -40 20 20 40 60 80 80 -60 -40 -20 20 40 60 80

'" ~

Distance east of storm center. n ml E

~ i:.

100

90

80 100

~ E 70 100

! 60 90 --- Radiometer

2!

~J i l! 50

~ :i 40 ~

80

70

----- P 3 INS

--- C 130 INS

o Scatterometer

~ 30

'" ~ 60 E

I 2! ~

100

C-13O INS Wind speed, mise<

10

60

170 --- Radiometer 50 ----- Ram radar

40

;;; 180 '" E ~ E

----- P 3 INS ~ 30

c --- C 130 INS ~

o Scatterometer

lO

OOOOL---L--~--~--~--~--~--~--~--~--~IOO

Radial distance from storm center, n ml Radial distance from storm center, n ml

F1gure 36.- F11ght tracks and results of m1crowave and a1rcraft sensor measurements for pass 4E.

100

E

~ ~ 0 ~

~

~

80

60 r-40 r-20 r-

20 r-40 r-

-60 r-

-80

~ E

I ~ c ; l! 3 '" ~

I ~

f

B

August 5, 1980 Pass 55

I I

I I -60 40

100

90

110

70

60

50

40

30

20

10

360

270 r-

I

I -20

I

Storm center 16oM'N, 7fP';4'W 11324 GMTI

I I I I I I I I I P-3 C 130 -

Ih=5OOml Ih=26oo-3000ml --

1315 GMT \

\ \

\ \

\

' 1303 GMT

1346 GMT

i -

\ 1331 GMT -

-I I I I I I ~ j I

20 40 60 110 -80 -60 -40 -20 20 40 60 80

Distance east of storm center, n ml

cx9 0

o~

o Radiometer

o SaHerometer

C-I30 INS Wind speed, mlsec

I I I I

/'_ .. \ ..... ,,.;' ........ -"-', ... , ... --""'-, I

I

100

I I I

-

/! -I

I , I ----- P-3 INS

--- C-I30 INS

o ScaHerometer -

~~~I __ j~~I~j~~I~l~~j~I __ ~I~ o W 20 30 ~ 50 60 ro 110 90 ~

Radial distance from storm center, n ml

~ 1! i!l E -"

~ r -" E

i

E E E

240

220

200

1110

90

80

70

10

50

40

30

20

W

I, I, Ii " (1 (I II (I

I' (I

: \I: ( I I :

I

: ,

--- Rodoometer ----- P-3 INS

---C-I~ INS

o Satteromoler

--- Rod,ometer

----- Roln radar

Radial distance from storm center, n ml

F1gure 37.- Fl1ght tracks and results of microwave and a1rcraft sensor measurements for pass 5S.

100

59

E

~ ~ '0

'" t:: ~

~ ~ C

60

August 5, 1980 Pass 6N

Siorm cenler 16°05 N, 700

57'W 1l3J8 GMTI

80

60

40

20

,lJ401 GMT I, I I T I

P 3

\ Ih=500ml - , , \

- \

1316 GMT

I I I I I I C 130 -

1402 GMT ( Ih=2600-l<XXlml

-, \ -

\ 1346 GMT ~

20 l-- 1!

~ -40 I- - E

-"

-60 - --1 c

I I I I I I 1 I I I I I '" -80 -60 -40 -20 20 40 60 80 80 -60 -40 20 20 40 60 80 !

Distance east of storm center, n ml ~

~ 100

120 90

80 100

~ E 70 S:> i

100

~ 60 8 ];! i

90 --- Radiometer

----- P-3 INS

jl 50

-5 (D

80

'" 11 70 ~

§ ~ 60 :E E

i 50 ~ ];!

40 ;:;:

100 30

C-13O INS wind speed, m/sec 20

\0

60

270 --- Radiometer ! 50 ----- Rain radar i ~ s 40

:;; 180 ~

'" E E

c 0

~ -0 ];!

'"'

----- P-3 INS

--- C-13O INS

o Scatteromeler

~ 30

c ~

20 090

10

Radial dIstance from storm center, n ml Radial distance from storm center, n ml

F~gure 38.- Fl~ght tracks and results of microwave and a~rcraft sensor measurements for pass 6N.

100

E

..!'

~ ~ '0

'" t: g

c ~ 05

August 5, 1980 Pass 7N

Siorm cenler 160 15'N, n0 22'W 11458 GMT I

80 I I I I I I I I I I I I 240

60 ~1443 GMT " P 3

Ih=l500ml C 130 -

Ih=26oo JtXX)ml 40 r- , , , 1503 GMT \ - 220

20 r- , \ \ \. -

-20 1500 GMT

r-1515 GMT

-

200 ~ i! 8-

-40 r- - E 180 ... -60 r- - ~

1 L I I I I I I I I I I ~ 80 -60 -40 20 20 40 60 80 -80 -60 -40 -20 20 40 60 80 ~

Distance east of storm center, n ml j " ~ 140

100

90 120

80 100

II!

100

90

80

10

~ 10

i 0

~ 0 60

1!!

? i l! 50

-5 " 40 I'!

--- Rldlomoter

----- P-3 INS

--- C-13O INS

o Satt ... meter

~

!! 60 E

~ JO ~ o Radiometer

20 o Scatterometer t 50

~ 40 ;0

10

100

C-13O INS WUl" speed, m/sec 20

J60 10

60

210

50

'" E E

... 40 > L! ;;; 180 c ~ i!

'0 ----- P-3 INS ...

ill --- C-13O INS ~

o Scatterometer

~ j

Radial distance from storm center, n ml Rid.,1 distance from storm center, n ml

F~gure 39.- Fl~ght tracks and results of microwave and aircraft sensor measurements for pass 7N.

100

61

62

80

60

~ 40 20

0 -0 € -20 2 ~ -40 ~

~ -60 C

I ~

~

I-

l-

l-

l-

I

I I

\ I I I I I I

1631 GMT & I I

~ -60 -40 -20

100

90

~

~ e 70

i 60 1! i 11 50

-5 " 11 40 ~

i 30 ~

20

10

August 5. 1980 Pass 85

Storm center 160 22'N, 7lo39'W 11553 GMT I

I I I I I I 1 I I P 3 C -130 -

(h=500 1500ml Ih = 2600-3000 ml --

1610 GMT 1515 GMT

~ i! i!l. E J!l

1'\ -\

\ 1530 GMT -

- ~ ~

~ I I I I I I I I I 20 40 60 ~ -~ -60 -40 20 20 40 60 ~

Distance east of storm center, n ml .;; E .5!

~

Q:)

° O~ )0 o Radiometer

~ E

o Scatterometer -i ~ 1! 3:

100

C-I30 INS Wind .peed, m/.ec

~,

,_.... .... __ ,,_..,_ ...... --_J~.t' ,-" ... .,,~ -............

.<:

E E

E ~

i! -0

----- P-3 INS

--- C-I30 INS j o Scatterometer ~

ii so ~

Radial distance from storm center, n ml

240

220

200

I~

100

100

90 -- Radiometer

----- P-3 INS

~ --- C-I30 INS

0 Scatterometer 70

60

50

40

30

20 \ \

10

60

50

40

30

20

Rachal distance from storm cenler, n ml

F1gure 40.- Fl1ght tracks and results of m1crowave and aircraft sensor measurements for pass 8S.

100

E

! i "0 ~ 1: g

~ C

August 5, 1980 Pass 9S

Storm center 160 24' N, 71045' W 11612 GMT I

80 I I I I I I I I I I I I 240

60 t- P 3 C 130 -Ih= 1500ml Ih=16OO-JOOOml

40 t- - 220

20 - -1654 GMT 1547 GMT

-20

-40

~ 200

'i! !l. E 180 ...

, , -

\ 1530 GMT -

, , - I

/ -

I -60

c -- 1635 GMT,'

-80 '" ! ~ ~ J ~ I I I I I' I I 1

20 40 60 80 -80 -60 -40 -20 60 -40 -20 20 40 60 80

Distance east of storm center, n ml ~ ~

100

90

80 100

~ E 70 100

i 60 \:0 90 ~ i E 50 80 -5 <ll>~ '" 40 ::l 70

--- Radiometer

----- P-J INS

--- C 130 INS

o Scatterometer

~ ~ 60

~ E

i ~

50

~ 40

100 30

C-l:11 INS Wind speed, m/sec 20

360 10

'\ --- .... ---... ~ ... - 60 I \ , \ ,..,_ ... -

270 r/

/"y---....

~ V----;;: 50

€ ( -"----~ / '------- E g -' E

J3 I I

( ... 40 , ~ :;;; 180 I c ~ / i! I C I

"0 0 I 30 ~

, ----- P-3 INS ... ,

§ i; --- C-l3O INS ~ "ii ;;: 0 Scatterometer

~ 20

090 E

" ~ 10

000 0 100

Radial distance from storm center, n ml Rad~1 distance from storm center, n ml

F1gure 41. Fl1ght tracks and results of microwave and a1rcraft sensor measurements for pass 9S.

100

63

E

$ e ~ <; .c 1:: l! ~

~ .5

64

August 5, 1980 Pass 1(l.J

Storm center 160 26'N, 7lo50'W 11626 GMT!

80 I I I I I I I I I I I I 240

60

40

r P J 1 h = 1500 m 1 1707 GMT

r , I

C -IJO -

1558 GMT Ih=26oo-JOOOml

- 220

20 I I

r f f

\ -" I

-20 I 1654 GMT

r 1547 GMT

-

200 ~ 1!

40 I-- - 1:. e 180 $

60 I-- -~

80 I I I I I I I I I I I I

60 -40 20 20 40 60 80 80 60 40 -20 20 40 60 80 :c ~ 160

Distance east of storm center, n ml $

1:: 2

~ 140

100

90 120

80 100

~ E 70 100

-i ~ 60 90 -- RadIOmeter 2! i ----- P-J INS

]I 50 80 ---C lJO INS

-3 '" :'l 40

0 Scatterometer 70

i JO ~ o Radiometer

~ 60 E

20 o Scatterometer i 50 ~

to ~ 40 ~

JO 100

C-lJO INS Wind speed, mlsec 20

160 I I I I I I I I I 10

60

270 - -! 50 .c .c

~ E e

" > ~ 40

~ 180 r - ~

i! ~

~ i;

2! ,---, ....... _---------,-.....

----- P-J INS

--- C-lJO INS

<; JO

~ :i o Scatterometer

-20

ii S!

~ to

I I I I I I I I I OOOOL---ILO---2O~--~JO~--4OL---50~--~60~~70~~80~~90~~I00

Radial distance from storm center, n ml Rachal distance from storm center, n ml

F1gure 42.- F11ght tracks and results of microwave and a1rcraft sensor measurements for pass 10N.

100

E

~ i '0 ~ t: g

c

~ C

80

60

40

20

-20

40

60

80

I I I -

-

-1720 GMT --

---

I I I 60 -40 -20

100

90

8(]

~ E 70

t 60 c i

~ 50

~ 1l 40

i 30

:ii! 20

10

Storm center 160 28'N, n056'W (1643 GMT!

I I I I I I P J

Ih=1500ml

1558 GMT \

\ 1729 GMT

I I I I I I 20 40 60 110 -SO -60 40 -20

Distance east of storm center. n ml

o

o ~o

o

o Radiometer

August 5. 1980 Pass lIN

I I I C 130 -

Ih = 2600 J(XX)ml -

-

1609 GMT ~ - i'! :!l

- E

"" -

c

I I I ~

r 20 40 60 80

~ ~

!t E

o Scatterometer 'j,-

~ ~ ;:

100

C-lJO INS Wind speed, mise<:

~Or---r---,---'----r---r---.---'---'r---r---.

240

220

200

1110

160

100

100

90 -- Radiometer

----- P J INS SO --- C-lJO INS

o Scatterometer 70

60

50

60.--.--,--,--,--,---,--,---'--'--,

270

~ 180

c o

-g ii

~ ;:

090

----- P-J INS

--- C-lJO INS

o Scatterometer

Radial distance from storm center, n ml

50 ~

E E

40

30

Radial dlstince from storm center, n ml

F1gure 43.- F11ght tracks and results of microwave and aircraft sensor measurements for pass 11N.

I I

100

65

E

~

~ " € <!

co ;';! 0

66

August 5, 1980 Pass 12S

Storm center 1603Q'N, 72oOl'W 0659 GMT)

80 I I I I I I I I I I I I 240

60 I- P J C lJO -I h = 1500 m I Ih = 2600 JOOJ ml

40 I- - Z20

20 "- -

-20 mo GMT --- ------

- 1750 GMT

1610 GMT '- 1616 GMT -

200

~ ~ :!l

40 - - E 180 .., -60 f- - co

60 -40 -20 20 40 60 IK) -IK) -60 -40 20 20 40 60 IK) 80 I I I I I I I I I I I I :c

~ Distance east of storm center, n ml 'li

13 ~

100

120 90

IK) 100

~ E 70 100

i 0 00 ~ 60 90 -- Ra<hometer co i ----- P-3 INS

~ 50 80 ---- C-1JO INS

~ ::l 40 70

o Scatterometer

~ JO ~

o Radiometer ~ 60 E

20 o Scatterometer i ~

50

10 -g

40 ~

JO 100

C-l]) INS Wind speed, m/sec 20

J60 I I I I I I I I I

10

60

270 - -50

~

E E

40 ~

- co i!

" JO ----- P-J INS

--- C-1JO INS j o Scatterometer

-20

~ ~

10

I I I I I I I I I OCOO~--lLO---2~0--~JO~~40~~5O~--60~--770~~IK)~~90~~loo

Radial distance from storm center. n ml Radial distance from storm center n ml

F1gure 44.- F11ght tracks and results of m1crowave and a1rcraft sensor measurements for pass 12S.

100

E

c ~ u

i '0 .c

~ c ~ C;

August 8, 1980 Pass l3E

Storm center 24o lll'N, 9i'00'W 11902 GMT)

80 I I I I I I I I I I I I

240

60 r- P J C 130 -Ih= 1500m) )h= J200-J700m)

40 r- - 220

20 r- -

20

1859 GMT , , - ................... -

'-

1934 GMT f", '-., -

........

~ 200

i§ ~

40 - 1830 GMT , "'- E ISO ..,

-60 - 1850 GMT~ c

80 I I I I I I I I I I I I

60 -40 -20 20 40 60 80 -80 -60 -40 -20 20 40 60 80

.c ~

160 ii Distance east of storm center. n rnl j

8! 140

100

120 90

80 100

~ E 70 100

<i ~ 60 90 -- Radiometer c

" ----- P-j INS

~ 50 80 --- C-lJO INS

~ 0 Scatterometer ~ 40 70 . ~ 30 ~ 60 iF: E

20 1 50

10 c 40

'" 100

30

C-lJO INS willd speed, mlsec 20

J60 I I I I I I I I I

60,---.---.---.---,---,---,---,---,----,--,

270 r- --- Radiometer

50 ----- Rain radar

40

.c E E

----- P J INS

--- C-lJO INS

o Scatterometer -

I I I I I I I I I OOOOL---I~0--~2O~~3O~~4O~~50~--~6O~-770~~80~~90~~100

Radial distance from storm center n ml Radial distance from storm center, n rnl

F~gure 45.- Fl~ght tracks and results of m~crowave and a~rcraft sensor measurements for pass 13E.

100

67

E

i ~ '0 ~

l: g

2! ~

68

August 8, 1980 Pass 14W

Storm center 24oU'N, 92oOS'W ~1918 GMTI

80 I I I I I I I I I I I I 240

60 I- P l C 130 -Ih = 1500 m I Ih = 3200 3700ml

40 I- - 220

1914 GMT 1938 GMT 20 I- , , -, , '--- -

"

20

,

1859 GMT

-- 1921 GMT

- i 200

~ ~

-40 c- - E 180 " 60 l- - ~

-80 I I I I I I

60 40 20 20 40 60 80 -80 -60 -40 -20 20 40 60 80 I I I I I I ~

~

160 ii Distance east of storm center, n ml ;:;

E

~ 140

100

120 90

80 100

!! E 70 100

t 60 90 --- RadKlmeter -g

0 i ----- P 3 INS

!! 50 0 80 --- C-I30 INS -5 rt1J& '" 40 ~

0 Scatterometer 70

~ 30 ;;; o Radiometer !! 60

E

20 o Scatterometer ai 50 ~

10 -g

40

" 100

30

C-lll INS Wind speed, mlsec 20

~'-~I--'-I~I--~I~I--~I--'-I~I--~I~

270 - -! ~ l: :;> J3

:;; 180 - -~ ~ 0

~ ----- P 3 INS i;

-g --- C-I30 INS

" o Scatterometer 090 I- -

Radial distance from storm center, n ml Radial distance from storm center, n ml

F~gure 46.- Fl~ght tracks and results of m~crowave and a~rcraft sensor measurements for pass 14W.

100

E

~ ~ '0

€ g

~ 05

August 8, 1980 Pass 15W

storm center 24° 12'N, 9frfl'W 119)4 GMT I

80 I I I I I I I I I I I I

240

60 - P J C 130 -Ih=l500ml Ih=J200-J7ooml

40 - - 220 1914 GMT 1939 GMT

20 - " , , '"

~ -

,

-20 1929 GMT

r-1954 GMT

- ~ 200

1! ~

-40 r- - E 180 J!l

60 r-I I I I I I

-

I I I I I I ~ 80 -60 -40 -20 20 40 60 80 -80 -60 -40 -20 20 40 60 80 r 160

ill E II ~ -g i

~ ~ ~

~ :iE

Distance east of storm center. n ml

100

90

80

10

60

o 50

40

30 o Radiometer

20 o Scatterometer

10

10 100

C-1Jl INS willd speed, mlsec

210

----- P-J INS

--- C-1Jl INS

o Scatt.ramel.r

\

\ \ ------~::-:::::::--:::; I 'I - .... -- ..r----

OCOo~"~~~\'L---~--~~~~~~--=---~--~--~--~ 100

Rachal distance from storm center, n mt

J!l 1! " ~ 140

120

100

100

90 -- RadIOmeter

----- P-J INS

80 --- C lJlINS

0 Scatterometer 70

~ 60 E

t 50

-g ~

20

60

50

40 ~

E E

~ Jl

c

~ 20

10

Radial distance from storm center. n ml

F1gure 47.- Fl1ght tracks and results of m1crowave and aircraft sensor measurements for pass 15W.

100

69

e

c

~ "0

'" t g

c ~ 0

70

August 8, 1980 Pass 165

Storm center 240 13' N, 92° 13'W (1951 GMT)

80 I I 1 I I I I 1 1 1 1 1 240

60 r- P 3 (h=lSOOm)

C 130 -Ih=3200 3700 m I

40 ~ - 210

10 ~ -

10

-40

60

1929 GMT

r-I

r- I I

I

r- 1944 GMT I

1957 GMT

I -/ -

I

2014 GMT / -

~ 100

~ ~ 180 ~

c

1 1 1 I I I I I 1 1 1 I 80 60 40 10 10 40 60 80 -80 -60 -40 -10 10 40 60 80

'" r 160

Distance east of storm center n ml ~ ~ 140

100

110 90

80 100 ill ~ 70 100

i fit 60 90 -- Radiometer -g i ----- P-3 INS

~ 50 80 --- C-I3O INS

3 '"

0 Scatterometer ~ 70

i ~

~ 60 E

i 50 ~ -g

40 ~

100 30

C-IJl INS Wind speed, m/sec 10

10

I

.,(_./---"'~--';_/=-cI,-:f ..,,.::--' ...... -..,-,--/ 270

~

60 I 1 1 1 T I I 1 1

-- Radiometer 50 - ----- Rain radar

'" 8 , J3 40-

I I

> ~ 180 ~ c 0

~ i5 -;;> ~

090

----- P-3 INS

--- C-I3O INS

o Scatterometer

~L--L __ ~~ __ ~~~~~~~~~~ o ~

II

'" ~ E 'I E "

lO- " ! " i.! ll~ c

" ~ I I II

10-I I

" I ' II , I ,I I

107. ' ,I

" 1'1 1: I 1" Ir f',,'_ " i \

I I' I'~, 1 1 I I I I I 10 10 30 40 50 60 70 80 90

Radial distance from storm center, n ml Radial distance from storm center, n ml

F1gure 48.- Fl1ght tracks and results of microwave and aircraft sensor measurements for pass 168.

-

-

-

-

-

100

E

~ ~ '0 ~ 1: g

~ c;

August 8, 1980 Pm 17S

Storm center 24° 14' N 920 17'W 12007 GMT!

80 I I I I I I I I I I I I 240

60 t- P 3 C -130 -Ih= 15OOm) Ih=32oo 37oom)

40 r-- - 220

20 r-- -

-20

40

-60

2000 GMT

r-- I

/ I

r-- / r-- I

I 195~ GMT1 -

I I I

2032 GMT/ -I

I I -

J -I 20141GMT I

I I I

~ 200

i! :!:. E ISO '" c ~

-80 -60 -40 -20 20 40 60 SO 80 -60 -40 20 20 40 60 80 ~ 160

Distance east of storm center, n ml ~ ~ 140 ~

100

90 120

!IO 100

~ E 70 100

of ~ 60 90 --- Radiometer 2'

" ----- P J INS

~ 50 8 80 --- C-IJ! INS -5 0

~ 40 0 Scatterometer

70 l!

§ J! :i! o Radiometer ~ 60

E

20 o Scatterometer of 50 ~

10 0 2' 40 3:

100 3D

C-ll} INS Wind speed, mlsec 20

60

! 50 --- Radiometer

----- Rain radar ~

~ ., 40

:; 180 ~

~

E E

c 0

-g -- --- P-3 INS i! J!

~

2' 3:

--- C-1J! INS

o Scatterometer

c

~ 20

090

Radial distance from storm center, n rnl Radial distance from storm center. n ml

F~gure 49.- Fl~ght tracks and results of microwave and aircraft sensor measurements for pass 17S.

100

71

E

~ ~ " '" t: g

Ie! J)! c;

72

August 8, 1980 Pass IBN

80 I I I 60 I- P 3

Ih=l500ml 40 l-

20 -

20 -40 -

60 -I

80 60

100

90

80

!!( E 70

"il ~ 60 ~ i :g 50

-3 '" :'! 40

i lO

~

20

10

270

!! 180 1!

2000 GMT

I I 40 -20

I

Storm center 24oI5'N, 920 21'W (2024 GMT)

I I I I I I I I I ) 2018 GMT

I I

I

I I

I I

C III /2049 GMT -Ih= J2OO-17ooml

I -

I I -

2032 GMT -

-

-I I 1 I I I I I I

20 40 60 80 -80 -60 -40 20 20 40 60 80

Distance east of storm center. n ml

0

0 00

o Radiometer

o Scatterometer

100

C-III INS wind speed, mise<:

----- P 3 INS

1:.,.: ___ -.;;.:-~'--=~-4..;·~.A / --- C-III INS ~-- o Scatterometer

I

OOOO~--~--~--~--~--~--~--~--~--~--~Ioo

Radial distance from storm center. n ml

~ "i! ~ E .'!l

~ ~

'" ~ ~ .'!l E " ~

l!i E

i ~ "l! ;':

'" E E

~ ~

~

240

220

200

180

160

140

120

100

100

90 --- Radiometer

----- P-3 INS

80 --- C-III INS

0 Scatterometer 70

60

50 r./-"'\,I J"'!

40 I I

II

20

I 10 I

60

40

II

20

10

Radial distance from storm center, n ml

F1gure 50.- F11ght tracks and results of microwave and a1rcraft sensor measurements for pass 18N.

100

E

~ i '0 ~

t g

2! 'O! C;

80

60

40

20

-20

40

-60

80

August 8, 1980 Pass 19N

Storm center 2116 N, 920 25'W i2041 GMT)

I I I I I r p 3 2018 GMT c lJO -

Ih= 15OOm) I h = 3200 3100 m ) /2049 GMT _

/ -,

2105 GMT

-

-

-

I I I I I I so -so 60 40 -20 20 40 60 80

Distance east of storm center, n ml

100

90

80

~ E 10

t 60 e i

~ 50

~ 13 40

~ JO ;;; o Radiometer

20 o Scatterometer

lQ

100

C-lJ) INS wind speed, mlsec

~'-'I--~I--~I'I--~I--~I'I--~I--~I~

210 - -

~ 180 l- -

e o

~ ----- P 3 INS 'v----.......... .... __ ../"- ___ C-13O INS ,-',_.-,---=:-:::::::=::::=.:._---

o Scatterometer 090 I- -

~ I I I I I I I I OOOOL--~10--~20----JOL---4OL---~50--~60--~ILO--~SO~--90L---~100

Radial distance from storm center, n ml

~

~ E-'" e ~

i

'" E ~ ~

~ E

-i ~ 2' ~

~

E E

i! e .;;

240

220

200

ISO

160

140

120

100

100

90 --- Radiometer

----- P 3 INS

80 --- C IJI INS

0 Scatterometer 10

60

50

40

JO

20

I I I

60

--- Radiometer 50 ----- Rain radar

40

JO

Radial distance from storm center, n rnl

Fl.gure 51. Fll.ght tracks and results of microwave and al.rcraft sensor measurements for pass 19N.

100

73

~ ~ " .c

g

c

~ c

74

80

60 r-

40 r-

20 r-

-20 r-

40 ~

60 ~

-80

~ E i ~ c i

~ "" '" ~ ~

;E

~ .c

~ .e

-E c 0

~ ."

" '"

August 8, 1980 Pass 20£

Storm center 240 17'N, 920 29'W (2102 GMT)

I I I I I I I I I I I I P J C -130 -

Ih=l500m) Ih= J20Q-J)OOm) -

-

2034 GMT ---... " , , , , ,

2106 GMT -----21Jl G~"i'

2056 GMT -

-I I I I I I I I I I I I

60 40 20 20 40 60 SO -80 -60 -40 -20 20 40 60 80

Distance east of storm center, n ml

100

90

SO

70

60

50

40

JO o Radiometer

20 o Scatterometer

10

100

C-IJJ INS Wind speed, m/sec

~Or---'----.---'----'---'----.----'----'---'----'

270

i i I

180

090

\ \

\. ",~~--~~-:~---~,:,==:-~-,=<:::;,

o 0 0 0

----- P-J INS

--- C 130 INS

o ScaHerometer

OOOOL---L--~--~--~--~--~--~--~--~--~I00

RacHal distance from storm center, n ml

~

1! ~ E .., c .c

~ 0;

g ." I;!

~ E

10 ~

~

.c E E

1! c

~

240

220

200

ISO

160

140

120

100

100

90 ----- Radiometer

----- P-J INS

80 ---- C-13O INS

0 Scatterometer 70

60

50

40

60

----- Radiometer 50 ----- Ram radar

40

30

20

Radial distance from storm center, n ml

FLgure 52.- FlLght tracks and results of mLcrowave and aircraft sensor measurements for pass 20E.

100

80

E 60

40

u 20

~ a L -20

~ 40

~

~ 60 c;

-80

August 8, 1980 Pass 21E

-r-r-

I-

I-

l-

~ E ~

~ ~

~

~ ~

::l

~ e

"

'" o ~

Storm center 240 19'N, 9zD34 W (2126 GMT)

I I I I I I I I I I I I P J C 130 -

I h = 1500 m I Ih=J200 J700ml -

-

2118 GMT ----.......... , , " , ,

2156 GMT ..... , --~~MT

2056 GMT -

-

I I I I I I I I I I I I -60 40 20 20 40 60 80 80 -60 -40 20 20 40 60 80

Distance east of storm center, n ml

100

90

80

70

60

50

40

-i 30 o Radiometer

20 o Scatterometer

100

C IlJ INS Wind speed, mlsec

360 '--'-1--'--1-'1---'-1-,1,----,1-,--1.-1--,--1-,

170 r-- -

B

~ 180 J~~~'C::.:::...'....'-:.~ __ ..:::..--.;;::.::.::.~:.---' -

O9Or-

o 0 o o ----- P-J INS

--- C 130 INS

o Scatterometer

Radial distance trom storm center, n ml

-

~

~ E .., ~

'" ~ .:;

:5 '" Ii!

~ E

i ~

" ?i

'" E E

;;; ~

~

240

220

200

180

160

140

120

100

100

90 -- Ra(hometer

----- P J INS

80 --- C 130 INS

0 Scatterometer 70

60

50

40

30

0 DO 20

10

60

-- Radiometer 50

----- Ram radar

Radial distance from storm center, n ml

F1gure 53.- Fl1ght tracks and results of microwave and a1rcraft gensor measurements for pass 21E.

100

75

76

August 8, 1980 Pass 2?rN

Storm center 2l20'N, 920 38'W (2147 GMT!

0 I I I I I I I I I I I I 240

60 I- P 3 C IJ!J -Ih=1500mJ ih = 3200 3100 m i

01- 2216 GMT - 220

-2120 GMT

'-.'-......., --.......,

20

2118 GMT l-

2156 GMT -20 ~

200

" I- -40 ~ .§ 180

60 l- -c

I I I I I I I I I I I I 80 60 -40 20 20 40 60 80 80 60 40 20 20 40 60 80

'" ~ 160

Distance east of storm center, n ml ~ E

~ 140 I:. 100

90 120

80 100

:li E 10 100

1il 1* 60 90 --- Radiometer c

" ----- P-J INS

!! 50 80 --- C-Ill INS 3 '" 40 ~

0 Scatterometer 10

~

~ JI) :li 60

" E

20 o Scatterometer t 50

10 <' 40 ;;:

J!J 100 0

C III INS Wind speed, mlsec 20

360 0(1

1\

10

I I I

60

! '"

--- Radiometer 50

----- Ram radar 1:

8 g

40

:;; 180 ~

'" E E

0

~ ----- P J INS ~ JO

"E --- C-lJO INS

c

c

~

" 0 Scatterometer 20 ()9()

IO

100

Radial distance from storm center, n rnl Radial distance from storm center, n ml

F1gure 54.- F11ght tracks and results of m1crowave and a1rcraft sensor measurements for pass 22W.

100

E

~ ~ '0

~ g

c

~ C;

August 8, 1980 Pass 1J11

Storm center 14011'N, 9i'41'W 11113 GMTI

80 I I I I I I I I I I I I 60 r- P 3 C IJJ -

Ih=l500ml Ih=3200 3700 m I 40 r- 2217 GMT -

2150 GMT -.... 10 r- " , , , -

, -"----..,

21JJ GMT 1136 GMT -10 r- -

-40 r- -

-60 r- -

1 I I I I I I I I I I I 80 -60 -40 10 10 40 60 80 -80 -60 -40 10 10 40 60 80

Distance east of storm center, n ml

100

90

80

!!i E 70

I 60 --- Radiometer

c i ----- P 3 INS

~ 50 --- C-IJJ INS

0;

'" ~ 40 o Scatterometer

~ JO ~ o Radiometer

10 o Scatterometer

100

C-tl} INS Wind speed, mISe(

170 ~

--- Radiometer

.c ----- Ram radar t: 2 s

;;; 180 ~ c 0

~ ----- P-3 INS -0 --- C IJJ INS ~ ~ 0 Scatterometer

090

Radial distance from storm center, n rnl Radial distance from storm center t n rnl

F1gure 55.- Fl1ght tracks and results of m1crowave and aircraft sensor measurements for pass 23W.

100

77

~ ~ '0 ~

1:: g

c ~ c;

78

Augu'l 8 1980 Pass 24S

Storm center 24°22 N, 92°45 W (2231 GMTI

80 1 1 1 1 1 1 60 r--- P 3 C 130

Ih= 1500ml Ih= J200-J)OOml 40 f- 220

20 f-

20

40

I 2203 GMT

r--- I I

I

f- I I

I

, /

2237 GMT ~ 200

t! 1l. E 180 .'B

60 r--- 2219 GMT J

c

80 1 1 1 1 1 1

20 40 60 80 80 60 -40 20

.c ~

160 ~

Distance east of storm center n rnl ~ S!

~ 140

100

90 120

80 100

!! E 70 100

t 60 90 --- Radiometer ~ c i 0

----- P J INS

!! 50 80 --- C lJO INS

~ o Scatterometer ~ 70

~ !i 60 :E E

I 50

" 40 ~

JO 100

C-1JO INS Wind 'peed m/,,,, 20

360 ,---.1-,-----I-.I~-,-1-,---1-.1-,-----1-.1-.-----1---; 10

60

---- Racllomeler

50 ----- Ram radar

40

~ ISO- - .c E E

----- P 3 INS ~ 30

--- C-1JO INS c

.l1 o Scatterometer 20

090 r--- -

10

Radial distance from storm center. n rnl Radial distance from storm center, n ml

F~gure 56.- Fl~ght tracks and results of microwave and a~rcraft sensor measurements for pass 24S.

100

80

E 60

§ 40

i 20

"0 ~ -20 1: g

40 c

~ 60 05

-80

August 8, 1980 Pass 25S

Storm center 240

23'N, 9t'47'W 12250 GMT!

240 I I I I I I I I I r I 1

r- P 3 C 130 -Ih=l500ml

r-Ih=J200 3700 m'

- 220

r- -2321 GMT

2235 GMT

r- I I

I I

r- I I

r- 2219 GMT ,;

I I I I I I

I -I

I

I -

12JOOIGMT I -

I I I 60 -40 20 20 40 60 80 -80 -60 40 -20 20 40 60 80

~ 200

~ ~ E 180 .., c ~

~ 160

Distance east ot storm center, n ml ~ ~ 140 I:.

100

120 90

80 100

!l: E 70 100

I 60 90 --- Radiometer c i ----- P J INS

]I 50 80 --- C 130 INS

~ 0 5catterometer ::l 40

~ >

70

~ 30 :iE o Radiometer

!l: 60 E

20 o Scatterometer

I 50

10 ~ 40

100 30

C-IJ) INS Wind speed, mlsec 20

10

~.

,,----,----~-.:~.::==--n-D--60

170 ~

€ :;> J3

~ 180 f!

I --- Rac:llometer 50 ! ----- Rain radar

'I 'I

40 " II ~ ,I E ,I E I

c 0

~ ----- P-J INS -Q --- C-13O INS ~ ~ 0 Scatterometer

30 I

~ I ,

c I ~ I

I 20 I

090 I I I

10

OOOOL---L---L--~---L--~--~--~--~--~--~Ioo

Radial distance trom storm center, n ml Radial distance from storm center, n ml

F1gure 57.- F11ght tracks and results of microwave and aircraft sensor measurements for pass 258.

100

79

E

c

i '0 ~ 1:: g

2! ~ C;

80

August 8, 1980 Pass 26N

Storm center 24"24' N, 9t' 48' W 12J02 GMT I

80

60 r- I pi 3 I I (I I

" 2256 GMT

I I I I I I C 130 -

240

40 Ih=l500ml I

f- , I (

Ih= 3200-3700ml - 220

20 I

f- I I

/ 23JO GMT -I

2235 GMT 2J21 GMT 200

20 f- - " i§

-40 f- - :!l E 180 $

-60 r-I I I J J J

-I I I I I I

-80 -60 -40 20 20 40 60 80 80 -60 40 20 20 40 60 80 !

160 .i5 Distance east of storm center, n ml ~

~ 140

100

90 120

80 100

!! E 70 100

i 0 60 0 90 -- Rachometer

~ 0 i ----- P-3 INS

]I 50 00 80 --- C-1J! INS ~ 00

" 0 :'! 40 r ~ JO ~ !5l o Radiometer

70

!! 60 E

o Scatterometer

20 o Scatterometer i ~

50

10 ~ 40 ;<

100 J! o o

C-IJ! INS Wind speed, m/sec 20

J60 I I I I I I I I I 10

60

270 r- -50

~

E E

----- P-3 INS ~ 40

--- C-1J! INS

o Scatterometer

- c i! '0 J! $

/---:;;---:.:::.:~-..-:.:::- ... ---.... --------... ,,,,,---,,--.... -t- 0

090 ;i 0 -

! ~ E

!

Radial distance from storm center, n ml Radial distance from storm center, n ml

F1gure 58.- F11ght tracks and results of m1crowave and a1rcraft sensor measurements for pass 26N.

100

APPENDIX A

SENSOR DESCRIPTIONS

A.l Sensors

A.l.l Radlometer

The stepped frequency mlcrowave radlometer lS a precislon, nadlr-looklng, Clrcu­lar polarlzed radlometer deslgned, developed, and fabrlcated at NASA Langley Research Center. The radlometer lS belleved to be the flrst variable-frequency mlcrowave ra­dlometer controlled by a dlgltal microprocessor that provldes both radlometer control functlons and real-time data processlng. The radlometer antenna, microwave portlon, and slgnal processor are shown In flgure Al. The front panel of the dlgltal control­ler lS shown In flgure A2.

The radlometer is capable of operating at frequencles between 4.5 GHz and 7.2 GHz at bandwldths of 10, 50, 250, or 1000 MHz wlth lntegratlon times from 0.2 to 20 sec. The frequency can be varled In incremental steps from approxlmately 0.2 to 5 tlmes the bandwldth per lntegratlon tlme. Durlng Hurrlcane Allen, the radiometer was operated In one-, two-, and four-frequency modes. Analysls has shown that the radlometer exhlblts an absolute preclsion of better than 2.0 K. Removal of absolute lnstrument blas was accompllshed through comparlson of the known local sea-surface temperature (26°C) Wlth the physlcal sea-surface temperature calculated from the brightness temperature at that locatlon. Wlnd speed and sea-surface sallnlty were taken lnto account In this comparlson. The 1deal radlometrlc brlghtness temperature sensltlvltyof the lnstrument varles between 0.012 and 1.25 K, dependlng on the band­wldth and lntegratlon tlme selected for the radlometer. The measured radiometer sen­Sltlvity at 6.6 GHz was between 0.69 and 0.88 K wlth 90-percent confidence, and between 0.65 and 0.94 K wlth 99-percent confldence. For the Hurrlcane Allen experl­ment, the ldeal radlometer sensltlvlty was 0.25 K. The radlometer was operatlng wlth a predetectlon fllter bandwldth of 50 MHZ, and an lntegratlon time of 0.2 sec, wlth flve samples averaged durlng post-fllght data reductlon to achieve a sample period of 1 sec.

The radlometer lS a balanced Dlcke-swltched square-wave correlated radlometer. It utlllzes a closed-loop nOlse feedback clrcult to add nOlse to the received antenna nOlse and thereby balance to the Dlcke reference nOlse. The mlcrowave portlon of the radlometer, lncludlng the broadband tunnel-dlode low-nolse ampllfler, lS malntalned In a constant-temperature enclosure at the Dicke reference temperature wlthln ±0.10 K. A block dlagram of the radiometer lS shown In flgure A3.

The antenna conslsts of a corrugated-wall broadband horn (the 10-dB beam wldth for clrcular polarlzatlon lS 20.5°). The antenna has a polarlzing radome to provlde for clrcular polarlzatlon. An 11-layer flberglass honeycomb-sandwlch radome lS used over the polarlz1ng radome In pressurlzed alrcraft. The feed of the antenna lS located wlthln the constant-temperature enclosure. The nOlse in]ectlon clrcult con­SlStS of a SOlld-state nOlse dlode, lsolator, PIN dlode switch, and 20-dB dlrectional coupler. The Dlcke switch lS a broadband latching clrculator.

The recelver portlon of the radlometer conslsts of a homodyne mlxer, YIG-tuned local osclliator, and 1- to 1000-MHz lntermedlate frequency (IF) ampllfler. The fre­quency of the radlometer lS controlled by an elght-blt dlgltal word from the digltal

81

sUbsystem that lS converted to 0 to 10 volts dc. ThlS slgnal controls the voltage­tuned mlcrowave oscl11ator. The frequency can be changed every 200 msec in steps of 16 MHz or greater over the frequency range from 4.018 to 8.098 GHz. However, the antenna 11mlts the usable frequency range to 4.500 to 7.200 GHz. The bandwidth of the radlometer lS selected by the dlgltal subsystem uSlng one of four paths through the fl1ter bank.

The 1- to 1000-MHz constant-power-level nOlse slgnal lS coupled by transformer lnto a hot-carrler dlode square-law detector ln the analog slgnal processor. The detected nOlse slgnal lS ampllfied, synchronously detected wlth the Dlcke switchlng frequency, and the resultant error slgnal is fed to a true lntegrator. The output of the lntegrator lS fl1tered to remove the effect of the Dicke switching frequency and lS used to control the pulse traln output of a voltage-to-frequency (V/F) converter.

The V/F converter provldes a variable-duty-cycle 70-~sec pulse traln. The pulse repetltlon frequency varles 11nearly from 0 to 10 000 pulses per second wlth the dc output voltage of the lntegrator. ThlS pulse traln lS applled to the nOlse-lnJection PIN dlode sWltch and controls the number of injected constant-amplltude, constant­wldth nOlse pulses. The dlgltal subsystem measures the duty cycle of the pulse train to determlne the nOlse added to the antenna nOlse.

The dlgltal subsystem provldes control functl0ns to the radlometer, data pro­cesslng of the output slgnal from the radiometer, and physlcal temperature measure­ments of several locatlons ln the radl0meter. It also provldes front panel control functions and real-tlme dlsplays for the operator. The radl0meter data are formatted along wlth tlme, temperatures, and other operatlonal data and are recorded on a dlgl­tal tape recorder. The lntegratl0n tlme of the radl0meter lS determlned by the count perl0d of the lnJectlon tlme counters WhlCh compute the duty cycle of the radiometer output. The lntegratlon tlme of the closed-loop radl0meter nOlse feedback lS several tlmes faster than the mlnlmum lntegratlon time allowed by the dlgltal subsystem.

A.1.2 scatterometer

The alrborne mlcrowave scatterometer (referenced ln earller 11terature as SUS, the Seasat underfllght scatterometer) lS an actlve mlcrowave remote sensor that was developed at the NASA Langley Research Center to measure the absolute normalized radar cross sectlon of ocean, lce, and land targets. The scatterometer operates in a "long-pulse" mode (lnterrupted contlnuous wave), at a center frequency of 14.6 GHz. A slmpllfled block dlagram lS shown ln flgure A4. The scatterometer 1S separated lnto three maJor assemblles: glmbal, transmltter-recelver assembly, and rack-mounted electronlcs.

The glmbal assembly compr1ses a dual-llnear polarlzed parabol1c antenna (3.5° beam wldth), a two-axis servo-controlled pedestal (to provide lndependent elevatlon and aZlmuth posltl0nlng), and a multl1ayer flberglass honeycomb radome. For Hurrlcane Allen, thlS assembly was mounted on the underslde of the fuselage beneath the vertlcal stabl1izer (tall sectl0n) of the C-130 alrcraft (flg. AS).

The transmltter-recelver assembly (fig. A6) conslsts of all the microwave hard­ware 1ncludlng clrculator sWltches, 1-W and 20-W travel1ng wave tube (TWT) power ampllflers, low-noise tunnel-dl0de amplifler (TDA), and a solid-state mlcrowave

82

source for generat1ng the transm1tter and rece1ver local osc1llator signals. The system operat1on 1S d1g1tally controlled by commands generated in the rack-mounted equ1pment.

The rack-mounted electron1cs (f1g. A7) cons1sts of power supp11es, the gimbal controller, the s1gnal processor, the d1g1tal controller and data system, and an analog strip chart recorder. The s1gnal processor (fig. A4) has two overlapp1ng channels that prov1de an 1nstantaneous rece1ved power range of greater than 30 dB. A programmable attenuator ~s used as a coarse ga~n control to increase the total dy­nam~c range to 60 dB. In each channel, the s~gnals are square-law detected, inte­grated for 500 msec, and then converted from analog to digital (A/D) and recorded with a 7-track d~g~tal recorder. The d1g~tal controller and data system is a m~croprocessor that generates the prec1se t1ming and control log1c needed by the scatterometer to form rad~o frequency (RF) pulses, operate sW1tches and range gates, convert analog 1ntegrator voltages to dig1tal, and format a1rcraft parameters and radar data needed for record~ng. The use of th~s processor enables cons~derable flex~b~l~ty in the select10n of radar operat1ng characteristics (table A1) V1a an 1nteract1ve programm1ng mode.

In making scatterometer measurements, the quantity of interest is the scatter~ng coeff1c1ent aO

• Th1s quant1ty 1S independent of the type of radar performing the measurement and 1S def1ned from the radar equat10n to be

where

P r

Pt

G

R

L

A

At

For the

rece~ved power

transm1tted power

antenna ga1n

slant range

mlscellaneous losses due to couplers, wavegulde, etc.

free-space wavelength

effect1ve area of antenna footpr1nt on surface

scatterometer case of beam-l1m1ted cond1tlons:

(S R) 2 'IT eq

At = "4 -c-o~s"--8-

(An

(A2)

83

where Seq ~s the effect~ve penc~l-beam antenna w~dth (approx~mately equal to the half-power antenna beam w~dth) and a is the inc~dence angle. The scatter~ng coeff~c~ent thus becomes

(A3)

The Pr/P t rat~o was measured ~n two steps. F~rst, a sample of the transmitter power, attenuated by a known value at, was d~verted ~nto the rece~ver, as shown in the block d~agram of f~gure A4. Th~s produced a "cal~brat~on" output voltage Vc ~n

each rece~ver channel, proport~onal to Pt. Next, the transmitter was connected to the antenna and an output voltage Vs proport~onal to Pr was obta~ned ~n a part~c­ular channel. Solv~ng for the rece~ved-to-transm~tted power rat~o (~n terms of the voltage from a part~cular channel) y~elds

where

V a c s

output voltage of ~ntegrator durlng surface observat~on

output voltage of ~ntegrat~on dur~ng cal~brat~on

recelver cal~brat~on loop attenuat~on

programmable attenuat~on dur~ng surface observatlon

programmable attenuat~on dur~ng cal~brat10n

F~nally, ~n terms of th~ scatterometer transfer funct~on, the express~on for 0

0 ~s

where h 1S the alt1tude of the a~rcraft (antenna).

(A4)

(AS)

The absolute aP value from equat~on (AS) ~s ~n error because of ~naccuracies ~n the determ~nat~on of the 1nstrument transfer coeff~c~ents (G, a, L, aI' and Seq) and the var~ables (h, a, and V). Th~s error can be separated ~nto ab~as and a random component. The accuracy of the b~as determ~nat~on ~s better than ±1 dB.

84

The maJor contr~butor to the random component of aO ~s vs' Because of Rayle~gh fad~ng of the rece~ved power from the surface, Vs is an imperfect est~mate of the mean rece~ved power used in the aO calculation, equation (A1). The normal­~zed standard dev~at~on of the cross section ~s approx1mately

flao

o a

1

iN

where the number of ~ndependent samples, N, ~s

N

(A6)

(A7)

where T 1S 1ntegrat10n t1me and 8d 1S the Doppler bandw~dth of rece1ved power,

2V f ---g-(s~n a - S1n a )

c max m~n (A8)

where

ground speed

radar frequency

c speed of l1ght

For Hurr1cane Allen,

After the conclus10n of the data fl1ghts, an interm~ttent d~g~tal command was found ~n the polar1zat~on sw~tch of the scatterometer. Thus, much of the August 8 scatterometer data ~ntended as HH polar1zat~on (see table A1) was discovered later to be actually e~ther HV or some mixture of HH and HV. This results ~n an uncerta~nty of several dB 1n absolute level of the HH, HV, and VH data. Therefore, for August 8, only VV data are useful.

There are two part~ally overlapp~ng channels ~n the s~gnal processor, as shown ~n f~gure A4. Arch~ved data tapes contain the calculated values of normalized radar cross sect~on (oP) for both channels. The value of e~ther was set to -99.00 or +99.00 if the ~ntegrator voltage for that channel was e~ther too low (noise dom1nated) or too h1gh (saturated), respect1vely. For the data f11ghts of Hurricane Allen, only the less sensitive channel was on scale 42 percent of the time, only the more sens~t~ve channel was on scale 47 percent of the time, and both channels were on scale s~multaneously 7 percent of the t~me. Dur~ng the rema~ning t~me, ne~ther chan­nel was on scale. The mean difference between the calculated values of aO for the two channels, near the saturat~on po~nt of the more sensit~ve channel, was about 0.6 dB w~th a standard dev~at~on of about 0.3 dB. (These statist~cs pertain only to VV polar1zat~on.) The total number of data po~nts (O.S-sec ~ntegration time) was

8S

10 075 for August 5 and 31 054 for August 8. The stat1~t1cs were nearly identical for the two days. (For the computat10n of these statistics and totals, HH.data for August 8 were not 1ncluded, for the reason discussed above.)

A.2 Sensor Footpr1nt Geometry

In order to make full use of the data obta1ned dur1ng Hurricane Allen, the sen­sor geometry and 1tS effect on temporal and spat1al al1gnment of the data must be understood. F1gure A8 11lustrates the arrangement of sensors aboard the NOAA C-130 aircraft dur1ng the Hurr1cane Allen mission. The stepped frequency microwave radiom­eter was set to look at nad1r; hence, 1tS footprint was d1rectly beneath the air­craft. The a1rborne m1crowave scatterometer, however, was operated at a variety of 1nc1dence angles from 0° (nadir) to 52°, and 1n all aZ1muths from the a1rcraft except for a 30° dead band centered on the a1rcraft nose.

Instantaneous footpr1nts on both sensors at nad1r would be nearly circular. However, because the sensors record data over vary1ng integration t1mes (usually 0.5 sec), there 1S a smear1ng of the footprint 1n the d1rection of the flight line. For example, g1ven a beam w1dth of 20.5° (0.37 rad), the instantaneous 10-dB foot­pr1nt of the rad10meter can be calculated from

Rad10meter footpr1nt diameter 0.37h

At an a1rcraft alt1tude of 3000 m the rad10meter instantaneous footprint would be a c1rcle w1th a d1ameter of 1110 m.

The footpr1nt 1S smeared, however, along the fl1ght 11ne by the d1stance the a1rcraft traveled dur1ng the s1gnal integrat10n. At an a1rcraft speed of 115 m/sec, the a1rcraft would have traveled 57 m during a 0.5-sec integration period. There­fore, the rad10meter footpr1nt would actually be an ellipse with the maJor axis along the fl1ght 11ne and the minor axis perpendicular to the fl1ght line. For the rad10m­eter, the t1me recorded was that t1me when the a1rcraft was d1rectly over the cen­tro1d of the smeared footpr1nt. Footpr1nt S1ze perpendicular to the fl1ght line is

A 0.37h

wh1le footpr1nt S1ze along the f11ght 11ne 1S

B A + 'TVg

For an alt1tude of 3000 m and a ground speed of 115 m/sec, footprint dimensions are as follows:

A 1110 m

B 1167 m

86

Calculat~on of footpr~nt s~ze for the scatterometer ~s slightly different because, ~n addit~on to smear~ng along the fl~ght l~ne, the instrument is not always nadir look~ng. The instantaneous footprint d~mens~ons A (perpendicular to fl~ght l~ne) and B (along fl~ght l~ne) for the scatterometer are

A

B

0.0612h cos a

A

cos a

where 3.5° (0.0612 rad) is the f~eld of view of the scatterometer. Aga~n, for an aLrcraft ~n motion, there ~s smearing along the flight line and B becomes

A B = -=-~a + TVg cos

For an altitude of 3000 m, an a~rcraft ground speed of 115 m/sec, and an ~nc~­dence angle of 45°, the scatterometer footprint s~ze for an aft-Iook~ng antenna ~s approx~mately

A 260 m

B 370 m

For the purpose of descr~b~ng the operat~on of the scatterometer dur~ng Hurr~cane Allen, the d~splacement of the scatterometer footpr~nt dur~ng an azimuth scan or an elevat~on scan ~s d~scussed here. Dur~ng an az~muth scan, the ~ncLdence angle of the antenna ~s held constant (with respect to the yaw ax~s) and the azimuth ~s var~ed ~n steps from 15° off one s~de of the a~rcraft nose through 330° to 15° off the other side of the nose. Meanwhile, the locus of footpr~nt locations on the sea surface LS the cycloid wh~ch results from the circular sweep of the antenna and the forward mot~on of the aircraft. F~gure A9 ~llustrates the loc~ of footprints for ~ncidence angles of 20°, 40°, and 54°, for an alt~tude of 3300 m, and a ground speed of 120 m/sec (typ~cal for the Hurr~cane Allen flights).

For a stra~ght and level fl~ght path over spat~ally varying but time-stat~onary surface targets, the geometr~cal concepts d~scussed above are of vital ~mportance. Although these concepts may 1n the future be applied to the analys1s of the m1crowave remotely sensed data of Hurr~cane Allen, they were not used in the present analysis beyond a prel~m~nary calculat~on of the scatterometer footprint locat~on. Our pres­ent 1~m1ted knowledge of the temporal and areal structure of the wind gusts and ra1n cells 1n the storm forced the scatterometer and radiometer data to be sorted accord­~ng to time and mean radial distance only. It ~s w~th a v~ew toward future analysis that the sensor geometry and footpr~nt locat~on concepts have been presented here. All parameters necessary for calculat~on of footprint location are available on the arch~ved data f~les, d1scussed ~n append~x B.

87

88

TABLE A1.- SCATTEROMETER OPERATING CHARACTERISTICS

Selectable characterLstLcs: PolarLzatLon • • • • • • • IncLdence angle, deg • • • • • • •• ••••• AZLmuth angle (relatLve to headLng), deg •

Nonselectable characterLstLcs: Frequency, GHz • • • • • • • or samplLng rate, sec- 1

Absolute or accuracy, dB • or precLsLon, dB • • • • Antenna beam wLdth, deg • • • • Total or range, dB • • • • • • • • •

HH,* HV, W, VH o to 54

15 to 345

• 14.6 2

• ±1.0 • ±0.1

3.5 +20 to -40

*TransmLt horLzontal and receLve horLzontal. WLth transmLt and receLve tLons. LS saLd

each horLzontal or vertLcal, there are four possible combina­When transmLt and receLve are of lLke polarLzatLon, the system to be Ln a dominant polarizat10n, and when opposed, 1n a cross-

polarLzat10n.

Mixer. loca I osci Ilato r. filter assembly

Data processor, controller (see fig. A3) Constant-temperature

electronic: enclosure

Signal

Figure A1.- Stepped frequency microwave radiometer. L-83-35

89

\.0 o

Figure A2.- Front panel of digital controller for radiometer.

£ .... 77 .... 4488

I I I Antenna - Microwave

subsystem '" - Receiver front end '"

A ~ ---

-- -

,Ii "- Analog Digital Driver -

--subsystem - circuits signal .-... processor

Figure A3.- Block diagram of radiometer.

1.0

\0 1\.)

Elevation/ azimuth gimba 1

Antenna

GIMBAL ASSEMBL Y-

Receiver port

Antenna port

Calibration attenuator

0.9,

Calibrate

High power

Solid­state source·

14.6 GHz

- Transmi tter port

Operate

TRANSMITTER-RECEIVER ASSEMBLY

I 14.4 GHz

I Ir'~----~--------

I

I I I

15 dB attenuator

3.

1_. _---I. __

I , I I I I I I I I

To digital controller

I SIGNAL PROCESSOR (Portion of rack-mounted

electronics)

Figure A4.- Block diagram of scatterometer.

Scatterometer antenna

(less feed and radome)

Figure 1\5.- Scatterometer gimbal assembly on C-130 aircraft.

Figure A6.- Scatterometer transmitter-receiver assembly.

93

~ w:::.

Signal processor

Digital controller

Gimbal controller

Power supplies

Figure A7.- Rack-mounted electronics for scatterometer.

Oscilloscope

Digital tape recorder

Interface panel

L-83-36

INS, raln radar

rladl r

Flgure A8.- Arrangement of sensors on NOAA C-130 for Hurrlcane Allen flights.

95

Flight line

Locus

Flight line

~ 5 mea red footp n nt, 6 sec

~IFOV

~~-,~ ~~;-t ~ , I

I I

~ I I I

Antenna aZlmuth-fl.

,,/

~ , I

r. I

I

~ I

of footpnnt ~ j", t--y*",

\

t" o

(a) e = 20 •

Centerline of smeared footpnnt I, '\ __ ~"'"

o (b) e = 40 •

Flight line , , I I I

}.

/\---\ ~ /'

I II

''''' ~/ )o.,jf

/ 11--- -1-~

I I I I

~

/

---{

1 I

I

/

I(

I /

\ f---,r:. \ " \ 'I-, A 1\'

, I

" ,f.,.. " I 'I,--x-- ,

o (c) e = 54 •

F1gure A9.- Locus of scatterometer footpr1nt for specified 1ncidence angles.

96

APPENDIX B

SCOPE AND FORMAT OF ARCHIVED DATA

Hurr1cane Allen data are ava11able to researchers 1n the form of d1g1tal tape from the Nat10nal Techn1cal Informat10n Serv1ce, 5285 Port Royal Road, Springf1eld, VA 22161. The archived 1nformat10n 1S compr1sed of e1ght files in all, namely, four of INS and rad10meter data, three of scatterometer data, and one of ra1n radar data. These f1ies are described 1n sect10ns B.1, B.2, and B.3. A supplementary section, B.4, prov1des some ancillary 1nformat10n to aid the computer programmer 1n the trans­fer of "card 1mage" tape 1nformation 1nto computer f11e space. In th1S append1x, time 1S expressed 1n dec1mal hours for conven1ence of the computer programmer.

B.1 INS and Rad10meter Data F11es

The content of the four f11es of compressed INS and radiometer data 1S given 1n table B1. In each f11e, the very f1rst 1nformat10n 1S an 1dent1fier with day, month, year, and nom1nal altitude 1n the f1rst four 10cat10ns, followed by 32 zeros. The data have three 12-word card 1mages per array of parameters, each with format F7.3, 3F9.4, 5F6.1, F6.0, 2F5.0. The parameters 1n the three card 1mages of an array are g1ven 1n tables B2, B3, and B4. The "ending t1me" shown 1n table B1 1S the "b1n 11m1t t1me" according to table B2, that 1S, the f1rst parameter of the f1rst of three 12-word card 1mages; these end1ng t1mes are prov1ded for convenience of a programmer 1n scann1ng the data.

Parameters 1, 2, 3, and 4 of the th1rd card 1mage are set to zero in the P-3 data, as are the two parameters assoc1ated W1th them, rain rate (parameter 9 of card 1mage 1) and est1mated surface w1nd speed (parameter 9 of card image 2). Otherw1se, the value 999 1S generally used as bulk f11ier 1n the INS and radiometer data.

For parameter 12 of card 1mage 3:

Code o 1S for good data

Code 4 1S exclusively for the C-130 on August 8, 1980, where a gap 1n INS data exists; only the b1n limit t1me and the radiometer TA data are mean1ngful; other parameters on the card 1mage are f111er.

Code = 2 1S for small gaps 1n INS data; the prev10us INS data are repeated as f111er, and are 1ncorrect for a Code 2 b1n.

Code = 1 1S for recovery from the Code 2 cond1t10n; change in radial d1stance and change 1n INS w1nd speed are set to zero; all other parameters are good.

B.2 Scatterometer Data F11es

The three f11es of scatterometer data respect1vely deal with vertical polariza­t10n on August 8, hor1zontal polar1zation of August 5, and vert1cal polarization on August 5. Each file is comprised of a s1ngle large record.

These data have two 12-word card 1mages per array, each with format 4F9.4, 2F6.1, F7.1, F5.0, 314, F8.1. The parameters 1n these two card 1mages are given in

97

tables B5 and B6. In each f11e, the first information is an identifier with day, month, and year in the f1rst three 10cat10ns, followed by five zeros, then an integer (1 for vert1cal polarizat10n or 0 for horizontal), and f1fteen tra111ng zeros.

The scatterometer b1ns are determined by t1me, elevat10n, and azimuth. Bin limit t1mes are frequently dupl1cated because of intermed1ate change of azimuth or elevat10n. There 1S no assurance of cont1nu1ty 1n the 1ncrement (0.004 hr) assigned for b1n 11m1t t1mes. These f11es have no f111er values.

B.3 Ra1n Radar Data Files

The ra1n radar f11e cons1sts of 33 records of t1me-averaged ra1n rates from rain radar measurements. These were provided at 1ncrements of 1 kID and have simply been stored. The format 1S 16F5.1, and (w1th f111 of zeros) 160 values have been stored 1n ten 16-value 11nes, pert1nent (except for zero fill) from 1 to 160 kID from the storm center. Values are 1n mm(hr. Descript10ns of the 33 records are listed in table B7.

B.4 structure of Archived Data Tapes

Each record of 1nformation 1n computer f11e space corresponds to a f11e of data on the arch1ved "card 1mage" tapes, and each card 1mage of data forms a separate rec­ord on tape. When the 1nformation is loaded from tape 1nto computer file space, the programmer must assemble the records appropriately so as to reconstitute just eight separately named and 1ndependent files. The INS and radlometer data are ordered accord1ng to table B1, read1ng down each column and from left to right as one would expect. The scatterometer data, 1n the same order as c1ted in section B.2 (i.e., vert1cal polarizat10n on August 8, horizontal on August 5, and then vertical on August 5), are followed by the ra1n radar data in the same order as listed in table B7.

98

TABLE B1.- PARTITIONED IN8 AND RADIOMETER DATA

-C-130, Aug. 5 C-130, Aug. 8 P-3, Aug. 5 P-3, Aug. 8

End~ng Endinq Ending Ending Record GMT,a Record GMT,a Record GMT, a Record GMT, a

hr hr hr hr

1 Approach A 11 .332 1 Approach 17.636 1 Approach 11 .500 1 Pass 13E 18.980 2 Approach B 11 .560 2 Approach B 17.932 2 Pass 1N 11.712 2 Pass 14W 19.232 3 Pass 1N 11 .740 3 Approach C 18.832 3 Pass 28 11 .960 3 Pass 15W 19.476 4 Pass 28 12.076 4 Pass 13E 19.340 4 Transit 1 12.412 4 Pass 168 19.732 5 Trans~t 1 12.632 5 Pass 14W 19.640 5 Pass 3W 12.600 5 Pass 178 20.000 6 Pass 3W 12.780 6 Pass 15w 19.904 6 Pass 4E 12.880 6 Pass 18N 20.292 7 Pass 4E 13.132 7 Trans~t 1 19.948 7 Trans~t 2 13.052 7 Pass 19N 20.568 8 Translt 2 13.512 8 Pass 168 20.236 8 Pass 58 13.256 8 Pass 20E 20.935 9 Pass 58 13.768 9 Pass 178 20.528 9 Pass 6N 13.660 9 Pass 21E 21 .296

10 Pass 6N 14.032 10 Pass 18N 20.812 10 Trans~t 3 14.016 10 Pass 22W 21.328 11 Trans~t 3 14.256 11 Pass 19N 21.088 11 Transit 4 14.400 11 Transit 1 21 .832 12 Trans~t 4 14.568 12 Pass 20E 21.512 12 Trans~t 5 14.712 12 Pass 23W 22.048 13 Trans~t 5 14.828 13 Pass 21E 21 .928 13 Pass 7N 14.992 13 Pass 248 22.320 14 Trans~t 6 15.052 14 Pass 22W 22.272 14 Transit 6 15.280 14 Pass 258 22.576 15 Pass 7N 15.248 15 Pass 23W 22.608 15 Trans~t 7 15.580 15 Pass 26N 22.940 16 Pass 88 15.496 16 Pass 248 23.004 16 Trans~t 8 15.856 16 Trans~t 2 23.312 17 Pass 98 15.780 17 Pass 258 23.352 17 Trans~t 9 16.160 17 Trans~t 3 23.552 18 Pass 10N 15.964 18 Pass 26N 23.500 18 Pass 88 16.520 19 Pass 11N 16.156 19 Departure 24.820 19 Transit 10 16.580 20 Pass 128 16.260 20 Pass 98 16.900 21 Departure A 16.500 21 Pass 10N 17.112 22 Departure B 17.632 22 Trans~ t 11 17.332

23 Pass 11W 17.488 24 Pass 12E 17.840 25 Departure 18.000

a The GMT, ~n dec~mal hours, of f~nal array (of 36 parameters) ~n record.

99

100

TABLE B2.- PARAMETERS IN CARD IMAGE 1 OF INS AND RADIOMETER DATA

B~n l~m~t t~me, hr from m~dn~ght 2 B~n average t~me, hr from m~dn~ght 3 Lat1tude N, deg 4 Long~tude E, deg 5 D~stance north of storm center, n.m~.

6 D~stance east of storm center, n.m~.

7 Rad1al d~stance from storm center, n.m~.

8 INS w~nd speed, m/sec 9 W~nd speed at surface est1mated from rad~ometer calculat~on, m/sec

10 Alt1tude, m 11 INS w1nd d~rect10n, deg 12 Bear1ng from storm center, deg

TABLE B3.- PARAMETERS IN CARD IMAGE 2 OF INS AND RADIOMETER DATA

1 L~qu~d water 1n a~r, g/m3

2 Hum~d~ty, percent 3 M~x1ng rat1o, g/kg 4 Dew po~nt, °C 5 A~r temperature, °C 6 Temperature measured w1th prec1s10n rad1at10n thermometer (PRT-5), °C 7 Change ~n rad1al d~stance from prev10us b~n value, n.m1. 8 Change ~n INS w1nd speed from prev10us b~n value, m/sec 9 Ra1n rate from rad~ometer calculat10n, mm/hr

10 Atmospher1c pressure, mbar 11 Hor~zontal angle between a1rcraft track and true north, deg 12 Hor~zontal angle between a~rcraft heading and true north, deg

2 3 4 5 6 7 8 9

10 11 12

TABLE B4.- PARAMETERS IN CARD IMAGE 3 OF INS AND RADIOMETER DATA

Rad10meter TA,l' K Rad~ometer TA,2' K Rad~ometer TA,3' K Rad~ometer TA,4' K A1r speed, m/sec Ground speed, m/sec P1tch, deg Roll, deg Vert~cal w~nd speed, m/sec Surface pressure, mbar Dr~ft (angle between a1rcraft track and a~rcraft head~ng), deg Code

TABLE BS.- PARAMETERS IN CARD IMAGE 1 OF SCATTEROMETER DATA

B~n l~m~t t~me, hr from m~dn~ght 2 B~n average time, hr from m~dn~ght 3 Lat~tude N, deg 4 Long~tude W, deg (note: w~thout m~nus sign, as recorded) 5 Rad~al d~stance from storm center, n.m1. 6 Bear1ng from storm center, deg 7 C-130 INS w1nd speed, m/sec 8 C-130 INS w~nd d~rect1on, deg 9 Arb1trary aZ1muth b1n 1ndex, based on a1rcraft heading

10 Arb1trary azimuth b1n index, based on INS w1nd d1rect10n 11 Arb1trary elevat10n b~n ~ndex 12 M1n~mum w~nd speed at surface est1mated from rad~ometer

calculat10n, m/sec

TABLE B6.- PARAMETERS IN CARD IMAGE 2 OF SCATTEROMETER DATA

Inc1dence angle, deg 2 Standard dev1at~on of 1nc1dence angle, deg 3 Norma11zed radar cross sect1on, dB 4 Standard dev1at1on of normalized radar cross sect1on, dB 5 AZ1muth angle, deg 6 Standard dev1at10n of az~muth angle, deg 7 Alt1tude, m 8 A1rcraft head1ng, deg 9 Number of scatterometer readings averaged 1n bin, negative if

rad10meter solut~ons for ra~n rate were not available 10 Scatterometer mode (see table 2) 11 Scatterometer polarizat~on (0 = HH, = VV) 12 Rain rate from rad10meter calculat10n, mm/hr

101

TABLE B7.- RAIN RADAR DATA

Record Date GMTa and bear~ng, or pass name

1 Aug. 5, 1980 11 .27 - 14.38 hr, all compass bear~ngs

2 Aug. 5, 1980 15.62 - 18.25 hr, all compass bearings

3 Aug. 5, 1980 11.27 - 14.38 hr, 350 0 to 10 0

4 Aug. 5, 1980 11.27 - 14.38 hr, 80 0 to 100 0

5 Aug. 5, 1980 11.27 - 14.38 hr, 125 0 to 145 0

6 Aug. 5, 1980 11.27 - 14.38 hr, 170 0 to 190 0

7 Aug. 5, 1980 11.27 - 14.38 hr, 260 0 to 280 0

8 Aug. 5, 1980 11 .27 - 14.38 hr, 305 0 to 325 0

9 Aug. 8, 1980 19.27 - 21.85 hr, all compass bearings

10 Aug. 8, 1980 20.90 - 23.10 hr, all compass bearings 11 Aug. 8, 1980 19.27 - 21.85 hr, 15 0 to 35 0

12 Aug. 8, 1980 19.27 - 21.85 hr, 102 0 to 122 0

13 Aug. 8, 1980 19.27 - 21.85 hr, 190 0 to 210 0

14 Aug. 8, 1980 19.27 - 21 .85 hr, 282 0 to 302 0

15 Aug. 5, 1980 C-130 Pass 1N 16 Aug. 5, 1980 C-130 Pass 2S 17 Aug. 5, 1980 C-130 Pass 3W 18 Aug. 5, 1980 C-130 Pass 4E 19 Aug. 5, 1980 C-130 Pass 5S 20 Aug. 5, 1980 C-130 Pass 6N 21 Aug. 8, 1980 C-130 Pass 13E 22 Aug. 8, 1980 C-130 Pass 14W 23 Aug. 8, 1980 C-130 Pass 15W 24 Aug. 8, 1980 C-130 Pass 16S 25 Aug. 8, 1980 C-130 Pass 178 26 Aug. 8, 1980 C-130 Pass 18N 27 Aug. 8, 1980 C-130 Pass 19N 28 Aug. 8, 1980 C-130 Pass 20E 29 Aug. 8, 1980 C-130 Pass 21E 30 Aug. 8, 1980 C-130 Pass 22E 31 Aug. 8, 1980 C-130 Pass 23W 32 Aug. 8, 1980 C-130 Pass 248 33 Aug. 8, 1980 C-130 Pass 25S

a GMT ~s ~n decimal hours.

102

APPENDIX C

RECORD OF ADDITIONAL INS AND RADIOMETER DATA

ThlS appendlx serves as a vlsual catalog of the INS and radiometer data not en­compassed wlthin the 26 defined pass palrs. These data pertaln to approaches to the storm, so-called "translts," and departures from the storm. Some of the transits are actually radlal profiles that could not be usefully matched lnto pass pairs, whlle others are translts ln the customary sense. Where the same radial distance is dupll­cated on a partlcular figure, necessarlly wlthln a reasonably short tlme lnterval, condltions can be lsolated for study of the extent to which the storm structure was relatlvely constant or subJect to relatlvely random devlatl0n. It lS not lntended that such flgures, or other flgures, be read for numerical values; these should be taken from the archlved data flles.

Of the INS data available, only wind speed and direction are of interest here. Consequently, for the P-3 alrcraft, the flgures dlsplay data for two flight segments, slde by slde. From the C-130 aircraft, radl0meter data are also available (except at extremes of approach and departure). Thus, the C-130 flgures dlsplay the flight path and the INS data on the left, the radiometrlc brlghtness temperature at the upper rlght, and (If the radiometer was operating at more than one frequency) the computed wlnd speed and rain rate. The fllght segments of these figures are ldentlfled 1n table C1.

Changes ln altltude shown on some flgures should be noted carefully, to preclude erroneous interpretat10ns. It is emphaslzed that these figures are lntended to serve as a key to avallable lnformat10n, and not as worklng tools themselves.

103

TABLE C1.- AIRCRAFT APPROACHES, TRANSITS, AND DEPARTURES

A~rcraft Fl1ght Alt~tude, GMT

Pos~t~on

and of

date segment m range storm center

p-3, Aug. 5 Approach A 400 1052-1115 15°55'N, 70 009'W Approach B 400 1115-1130 15°55'N, 70015'W

Trans~t 1 1500 1158-1225 15°58'N, 70031'W Trans~t 2 1600-500 1253-1303 16°02'N, 70046'W Trans~t 3 1500 1340-1401 16°07'N, 71°02'W Trans~t 4 1500 1401-1424 16°10'N, 71°08'W Trans~t 5 1500 1425-1443 16°12'N, 71°15'W Trans~t 6 1500 1500-1517 16°17'N, 71°26'W Trans~t 7 1500 1517-1535 16°19'N, 71°31'W Trans~t 8 1500 1535-1551 16°21'N, 71°36'W Trans~t 9 1500-300 1551-1609 16°23'N, 71°42'W Trans~t 10 1500 1631-1635 16°27'N, 71 ° 53'W Trans~t 11 1500 1707-1720 16°32'N, 72°06'W Departure 1600-4700 1751-1800 16°36'N, 72° 21'W

C-130, Aug. 5 Approach A 1700-4500 1026-1041 15°55'N, 69°59'W Approach B 4500-3100 1041-1113 15°55'N, 70007'W Approach C 3000 1113-1120 15°55'N, 70 013'W Approach D 3000 1120-1133 15°56'N, 70017'W

Trans~t 1 3000 1205-1238 15°59'N, 70 034'W Trans~t 2 3000 1319-1331 16°04'N, 70054'W Trans~t 3 2900 1402-1415 16°09'N, 71°07'W Trans~t 4 2900 1415-1434 16°11'N, 71°12'W Trans~t 5 2900 1434-1450 16°13'N, 71°17'W Trans~t 6 2900 1450-1503 16°15'N, 71 ° 22'W Departure A 3000-4300 1616-1630 16°26'N, 71°49'W Departure B 4300-6100 1630-1637 16°27'N, 71 ° 53'W Departure C 6100 1637-1659 16°29'N, 71°58'W Departure D 6100-1800 1659-1724 16°32'N, 72°06'W Departure E 1800-500 1724-1738 16°34'N, 72°13'W

P-3, Aug. 8 Trans~t 1 1500 2143-2150 24°20'N, 92°38'W Trans~t 2 1500 2257-2319 24°24'N, 92°38'W Trans~t 3 1500 2319-2339 24°25'N, 92°51'W

C-130, Aug. 8 Approach A 4600-5900 1640-1703 23°55'N, 91°27'W Approach B 5900 1703-1729 23°58'N, 91°33'W Approach C 5900 1729-1751 24°01'N, 91°39'W Approach D 5800 1751-1817 24°04'N, 91°46'W Approach E 5800 1817-1845 24°07'N, 91°53'W Approach F 5700-3700 1845-1850 24°09'N, 91°57'W Trans~t 1 3300 1954-1957 24°14'N, 92°14'W Departure A 3600-5600 2330-2350 24°26'N, 92°52'W Departure B 5600-6800 2350-2414 24°27'N, 92°53'W Departure C 6800-6200 2414-2439 24°29'N, 92°53'W Departure D 6200-1900 2439-2449 24°31'N, 92°53'W

a See text for descr~pt~on of frequency numbers. b See table 2 for descr~pt~on of modes.

104

Rad~-

ometer freq. a

2 2

2,4 4,1

4 4,1

1 1 1 2 2 2 2

4 4 4 4 4 4 4 4

Scatter-ometer F~g.

modeb

Cl Cl C2 C2 C3 C3 C4 C4 C5 C5 C6 C6 C7 C7

3 C8 2,3 C9 2,3 Cl0 2,3 Cl1 2,3 C12

8 C13 8 C14 8 C15 8 C16

2,8 C17 2 C18

2,3 C19 2,3 C20 2,3 C21

2 C22

C23 C23 C24

2 C25 2,3 C25

2 C26 2,3 C27 2,3 C28

2 C29 2 C30

2,3 C31 2,3 C32

2 C33 2,8 C34

E

~

~ 40

~ 20

'" '0 ~ 20 g

40

~ -60 .5

80 80

100

90

80

70

~

~ 60

'i ~ 50

1'! i ~

;:

II

20

10

J60

270

! co o

~ ~ 180 <! i V> ;:

Figure C1.

80

E 60

p-J Approach A

Storm center 15° 55' N, uP 9' W Ih=400ml

~ 40 P-J Approach B

~ 20 Storm center 15° 55' N, 7rf 15' W

i Ih=400ml

'0 ~ 20 t g

-40 ~ ~ -60 .5

100 120 140 160 180 200 220 240 -80 80 Distance east of storm center, n m. Distance east of storm center, n m.

100

90

80

70

~ 60 E

l 50

<! i

40 V> ;:

JO

20

10

J60

270

! g-~ ~

180

<! i

V> ;:

090

Distance from storm center, n ml Distance from storm center, n ml

F11ght track, INS W1nd speed, and INS wind d1rect1on for P-3 approaches A and B, August 5, 1980.

105

106

so SO E

60 P lTranlit I E

60 P lTranll! 2 .:

40 Storm center 15° 58' N, 70° 31' W

~ Ih=l500m)

~ 20

1215 GMT

.:' 40 Storm center 16° 2' Nt 70° 46' W

i Ih = 1600 to 500ml

20

~ '0 '0 1253 GMT ~ 20 g

~ -40

60 1158 GMT c;

~ -20 // 1:: g

-40 1303 GMT

~ -60 c;

SO SO -60 -40 20 0 20 40 60 SO 80 SO

Distance east of storm center, n ml Distance east of storm center, n ml

100 100

90 90

80 80

70 70

~ 60 E ~ 60 E

Ii ~ 50 i 50

];! i 40 ~

~

];! i

40 ~

!!;

l) 3D

20 20

10 10

360 360

270 270

f f <: 0

~ ;; ];! i ~ z

.:

~ 180 ISO ;;

1! i ~

!!;

090 090

10 20 3D 40 50 60 70 80 90 100

Distance from storm center, n ml Distance from storm center, n ml

F1gure C2.- F11ght track, INS wind speed, and INS w1nd direction for P-3 trans1ts I and II, August 5, 1980.

c i ~ z

80 E

60

~ 40

~ \

~ 20

1401 GMT

15 .c -20 P JTranSit 3 1: g Storm center 16° l' Nt nO 2' W

~ -40 Ch = 1500 ml

60 Q

-80 -80 60 -40 20 20 40 60 80

Distance east of storm center, n ml

lOOr--'---,---.---,---,---.--,---,---~-,

90

80

10

270

80

E 60 P-JTranSit 4

.:' 40 Storm center 16° la' N, nO 8' W

! Ch=l500ml 20

~ 1;; 1401 GMT 15 1424 GMT .c 20 1: g

-40 ~ ~ -60 Q

80 80

Distance east of storm center, n ml

100

90

80

70

jJ 60 e "of ~ 50

~ i

40 ~

,;

30

20

10

~ ~ c 0

~ ~ i ~ z

f 180 11

-0 ~ ;; ~

,;

090 090

Distance from storm center, n ml Distance from storm center, n ml

F1gure C3.- F11ght track, INS wind speed, and INS wind d1rection for P-3 trans1ts III and IV, August 5, 1980.

107

80 80 E

60 1443 GMT E 60 P 3TranSlt 6

~ 40

~ 20 \

~ 142S GMT

'"

~ 40 Storm center 16° 17' N, 71° 26' W ~ Ih = 1500 ml 1: 20 ~ '" '0 P-3Translt 5 '0

.c -20 Storm center 16° 12' Nt 71° 15' W t: g Ih = 1500 ml

~ -40

60 C

.c 20 t: g

-40 ~ ~ -60 C

80 -80 -60 -40 -20 0 20 40 60 80 -80 80

Distance east of storm center, n m. Olstance Nst of storm center, n m.

100 100

90 90

80 80

70 70

~ 60 E ~ 60 E

1 50 1 50

"l! i

40 '" !:

"l! i

40 '" !:

10

~~~I~I--~I~I~I--~I'-I~I--'-'I

270 f- - 2701- -

! ! ~ c g-~ ~ ;; 180 I- - ;; 180 - --g "l! i i

'" '" z !:

090 f- - 090 -

~

000 I I I I I I I I I 000 I I I 1 1 I I L 1 0 10 20 3~ 40 50 60 70 80 90 100 0 10 20 JO 40 50 60 70 80 90 100

Distance from storm center, n rnl Distance from storm center, n rnl

F1gure C4.- Fl1ght track, INS w1nd speed, and INS wind direct10n for P-3 trans1ts V and VI, August 5, 1980.

108

~ o

~

~ E

~ i V'>

~

100

90

go

20

10

J60

80 E

60 ~.

40 ! ~

20

10 <; .c -20 t: g

~ -40

60 C

-80 -80

I I

1535 GMT

Storm center 16° 19' E, 71° 31'W Ih = 1500 ml

-60 -40 -10 0 20 40 60 80 Distance east of storm center, n ml

I I I I I r I

-

i!! E

i ~ i

V'>

~

!' f

E

~

~ ~ 10 <; .c t: 8

~ ~ C

100

90

80

J60 I

270~

80

60 1535 GMT

40

20

-20 P-JTnnslt g

Storm center 16° 21' N, 71° 16' W 40 Ih = 1500 ml

-60

-80 80

Dlstlnce Nst of storm center, n ",I

I I I I I I I I

-

;; 180- ~ 180-;; -~ i

V'>

~

~ i

- -

I I I I I I I I I OOOO~--~10~~20~~~---~~~~~~60~~70~-80=-~90~~lOO

Distance from storm center, n ml Distance from storm center, n ml

Figure C5.- F11ght track, INS wind speed, and INS wind direction for P-3 transits VII and VIII, August 5, 1980.

109

80 80 E E

60 60 P-3Translt 9 P-3TranSit 10 .:"

40 Storm center 16° 231 N, nO 42 1 W .!" 40 Storm center 16° 27' N, 71° 53' W

~ (h= 1500 to JOOm) ~ Ih = 15(0)

10 10

~ ~ 1;;

1> 1551 GMT ..J 1>

" 10 1609 GMT .c -10 1: g g

-40

~ -40

~ 60 ~ 60 1631 GMT;;" 1635 GMT .:; .:;

-80 80 60 40 -10 0 -80 -60 80

Distance east 01 storm center, n rnt Distance east 01 storm center, n mt

100 100

90 90

80 80

70 70

~ 60 ~ 60 E E

l 50 l 50

~ -g "i i

40 40 '" '" :!O z

J) JO

10 10

10 10

J60 J60 I I I I I I I I I

(/

110 270 I- -

! ! ~ ~. 0

~ ~ 180 - -'0 is

~ ~ i "i '" '" :!O :!O

090 090 I- -

000 000 I I I I I I I I I 0 10 20 100 0 10 10 J) 40 50 60 70 80 90 100

Distance from storm center, n mt Distance from storm center, n mt

Fl.gure C6.- Fll.ght track, INS wind speed, and INS wind directl.on for P-3 transits IX and X, August 5, 1980.

110

80 80 E E 6IJ 6IJ .: 1707 GMT

P-3 Departure 40 ~ Storm center 16° 36' N, 72° ZI' W ! E 40

1: (h=l6IJDto4700ml

~ zo zo

~ '" '" -/1800GMT '0 P 3TranSit II '0 ~ -zo Storm center 16° 32' N, 72° 6' W ~ -20 .../ t: t: 175l GMT g (h=l500ml !!

~ -40

~ -40

-6IJ ~ -60 05 Q -80

-80 -SO SO Distance east Of storm center, n m, Distance east of storm center, n m,

100 100

9D 9D

80 SO

70 70

i!! 6IJ ~ 60 E E

l 50 l 50 "l;! -;

'" z

! g-~ .;;

~ i

'" ;!;

"l;! i

40 40 '" ;!;

1I 1I

zo zo

10 10

360 I I I I I I I I I 360

Z10 I-- - Z10

! o:

- - ~ ISO 180 .;; "l;! .. ~

D9D i- (, - D9D

000 I I I I I I 000 0 10 ZO 30 40 50 60 70 80 90 100 0 100

Distance from storm center, n ml Distance .rom storm cenwr, n ml

Figure C7.- F11ght track, INS w1nd speed, and INS wind direction for P-3 trans1ts XI and departure, August 5, 1980.

111

112

200 E

ISO

..... 160 ! 1026 GMT

~ 140 /

-.; 120 "0 1041 GMT '" 100 t: !! C 130 Approach A

~ 80

Storm center ISO 55' N, 69° 59' W -.; 60 (h ~ 1700 to 4500 ml Q

40 SO 100 120 140 160 180 200 220 240

Distance east of storm center, n ml

100

90

80

10

~ 60 E

i 50

¥ • 40 ~

~

JO

20

10

270

! c

~ 180

" l' • ~

~

090

Ridlil dl5tince from storm center, n ml

F1gure C8.- F11ght track, INS wind speed, and INS wind direction for C-130 approach A, August 5, 1980.

240

220

160 E

C-lJO Approach B 140 ~ .. 200

.: Storm center 150 55' N, )[1' l' W

! 120 I h = 4500 to 3100 m I l! 1041 GMT ~

~ 100 S

ao ~ 0

'" 60 r to g 1 III GMT

! ~ 40

2 20 ~ 140

05 0

60 220

Distance east of storm center, n ml 120

100100 200

Roolal distance from storm center, n ml

100 100

90 90

80 80

10 10 ~

ill '" e ~ 60

t 60

l 50 ~ 50 "l! i i

40 $ ~ ~ ;!:

i 30

20

10 10

10 360

60

210 50

'" ~

E e

~ SO i!

:@ lao ~ c

.;; i!

<; 30 i ~ ~

~ ;!:

20 090

10

000100 200 200

Radial distance from storm center, n ml Dlstlnce from storm center, n ml

F1gure C9.- F11ght track, INS wind speed, INS wind direction, radiometric brightness temperatures, rad10meter w1nd speed, and radiometer rain rate for C-130 approach B, August 5, 1980.

113

240

220

160 E

140 C 130 Approach C ~ 200

.: 120 Storm center ISo 55' N, 70° 13' W i!

~ Ih=JOO:)ml :!l. 100

E 180

~ ."

" 80 ! a .c 60 ~lllJGMT ! 160 t: g

~ ~ 40 1120 GMT

" " 20 ~ 140 0

40 60 80 100 120 140 160 180 200 Distance east of storm center, n ml 120

100 0 10 20 30 40 SO 60 70 80 90 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 ill 70

~ E

60 "i 60 E

i !

SO 2! SO i

2! i

40 .;; 40

U'> E ~ " ~ JO JO

20 20

10 10

70

J60

60

270 SO

.c E

! E .,,- 40

.g i!

j co

180 i!

" 30

• ~ U'> i;

~ ~

20 090

10

000 60 70 0 100 10 20 30 40 SO 80 90 100

Radial distance from storm center, n ml Distance from storm center, n ml

F~gure C10.- Fhght track, INS wind speed, INS w~nd direct~on, radiometr~c

br~ghtness temperatures, rad~ometer w~nd speed, and radiometer rain rate for C-130 approach C, August 5, 1980.

114

240

220

80 E

60 ~

200 1120 GMT

~.

40 ~ E ! llJl GMT ~ E

~ 20 ~ 180

~

~ "0 ~ -20 ! 160 ~ C III Approach 0

! -40 Storm center 15° 56' N, 70° 17' W ~

Ih=llOOmi " ...rv/ 60 ~ 140 Q

~ -so 80 80

120 Distance east of storm center, n ml

100 0 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 i!(

70

i!( E E 60 "i 60

l ~ 50 1! 50

c i

~ i 40 ~ 40

~ ~ z

~ -g JO '" JO

10 20

10 10

70 360

I I I I I I I I I

60

270 - - 50

~

~ E E

c 40 0

~ "@ c -c 180 - - ~ c JO i ~ ~ z

~ 20

090 - -

10

000 I I I I I I I I I 0 10 20 II 40 50 60 70 SO 90 100 100

Radial distance trom storm center, n ml Distance from storm center, n rnl

F~gure C11.- Fhght track, INS w~nd speed, INS w~nd direction, rad~ometrl.c

br~ghtness temperatures, rad~ometer w~nd speed, and radiometer rain rate for C-130 approach D, August 5, 1980.

115

116

240

210

80 E

60

.: C 130 TranSit 1

~ 40 Storm center 15° 59' N, 700 34' W

(h=lOOOmi

~ 10

1238 GMT ,. '0

~ 200

i! 8-.\l 180

~ .c -10 to 'I:( g

! -40

-60 .5 1105 GMT

r 160

~ ~ ! 1<40

80 -80 -60 40 10 10 40 60 80

Distance east ot storm center, n ml 110

~

100 0 100

Ra(hal distance from storm center, n ml

100 100

90 90

80 80

70 !!!

70

!!! 60 E E If 60

l 50 ~

~ ~ 50 i

i 40

'" " B 40 E 9 1i!

30 '" JO

10 10

10 10

70

60

270 50

.c

! E E

c B 40 0 ~

~ 180 i;

c :!

~ B JO ;;

'" ., ~ i; ~

10 090

10

100

Radial distance from storm center, n ml Distance from storm center, n ml

F1gure C12.- F11ght track, INS wind speed, INS w1nd d1rect1on, radiometric br1ghtness temperatures, radiometer w1nd speed, and rad10meter ra1n rate for C-130 trans1t I, August 5, 1980.

240

220

80 E

60 ~

200 ~

C-l3O TranSit 2

~ 40 Storm center 16° 4' Nt 10° 54' W E

!!. 20 Ih=lXXlml E

180

~ J!l

~ '0 ::: .c -20 1319 GMT ! 160 1:: Ii!

~ ~

~ -40

E

" -60 1111 GMT ~ 140 .:;

-80 -80 -60 40 -20 20 40 60 80

Distance east of storm center, n ml 120

100 0 10 10 30 40 50 60 70 80 90 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 l!!

70

a! E ~ 60 "'i 60

"'i §. §. 50 ~ 50

~ "i

i 40 t 40

'" ;; ~

30 30

20 20

10 10

70 I I I I T T T T 1 360 I I I I I I I 1 I

60- -

170 I- - 501- -.c

~ E E

"," 401- -~ 0 ~

~ - ~

180 I- ~ -0 -~ 0; 301-

" ~ '" ~ z

201- -090 I- -

10 I-

~ -

000 I I I I I I I I I I I I I I I I

0 10 20 3D 40 50 60 70 80 90 100 10 20 30 40 ~O 60 70 80 90 100

Radial distance from storm center, n ml Distance from storm center, n mi

F~gure C13.- Fl1ght track, INS WJ.nd speed, INS w~nd d~rection, radiometric br~ghtness temperatures, rad~ometer wind speed, and radiometer ra~n rate for C-130 trans~t II, August 5, 1980.

117

240

220

80 E

60 ~

200

~ 1402 GMT

~ 40 ~

20 ~

~ .., 180

~ '0 J: ~ -20 ! 160 t: g C 130 TranSit J

~ 40 Storm center 16° 9' N, 71° 7' W i

Ih=2900ml ~ 140 -60

.5 80

80 60 40 20 20 40 60 80

Distance east of storm center, n ml 120

100 0 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 ~

70

~ E

E 60 "i 60

l ~ 50 1! 50

1! i i

40 -!; 40 V> !i ;;:: ~

30

20

10 10

70 I I I I I I I I I J60 I I I I I I I I I

60 I- -

270 - - 50- -~

! E E

..,- 401- -c

~

g -c

180 f- ~ i;

-1! ~ 3Of-

" ~ z !

201- -090

~ -

10 - -

000 I I I I I I I I 1 I I I I I I I I I 0 10 20 JO 40 50 60 70 80 90 100 10 10 JO 40 50 60 70 80 90 100

Radial distance from storm center, n mt Distance from storm center, n rnt

F1.gure C14.- Fl1.ght track, INS wind speed, INS wind direct1.on, rad1.ometric br1.ghtness temperatures, radiometer w1.nd speed, and radiometer rain rate for C-130 trans1.t III, August 5, 1980.

118

80

70

II! ~ 60

<i ~ SO ~

! 40 ~

]60

270

~

" 0

~ i;

180

" i ~ z

090

(\XI

80 E

60 C 130 Transit 4 ~

40 Storm center 16° II' N, 71° 12' W

~ Ih=2900mJ

~ 20

,. 15

'" -20 t:: 2

~ -40

1434 GMT -60

0 -80

-80 -60 40 20 20 40 60 80 Distance east of storm center, n ml

I I I I I I I

I-

~

r--

I-

I I I I I I I 0 10 20 }) 40 50 60 70

Radial distance from storm center, n ml

240 ,-----,----,----,--r--,----.--,--,---,----,

220

'" ~ 200

1! :!l ~ ISO

" '" .:; 160

~ E

~ 140

120

Radial distance from storm center, n ml

I I

-

-

-

I I 80 90 100

F~gure C15.- Flight track, INS w~nd speed, INS wind direct~on, and rad~ometr~c brightness temperature, for C-130 trans~t IV, August 5, 1980.

119

120

80 E

60 C 130 TranSit 5

~ 40

Storm center 16° 13' Nt 71° 17' W $ Ih·2900mJ ~

20

~ 1450 GMT

'0 .c 20 1:: ~

~ -40

1434 GMT -60

is -80

80 -flO 40 20 0 20 40 60 10 Distance east of storm center, n ml

100

90

10

70

JJ 60 E

l 50

"!! i '" :::

160 I I I 1 I -r I

270

~ l §.

'ii 180 I-.5 "!! i

'" z

090 I-

000 I I I I I I I 0 10 20 JO 40 50 60 70

Ridlil distance from storm center, n ml

I I

-

-

-

I I 80 90 100

220

~

! 160

120

looL-~ __ -L __ -L __ ~ __ L-~~~ __ -L __ ~~

o 10 20

Radial dlslitnce from storm center, n ml

Figure C16.- Fl1ght track, INS w1nd speed, INS wind direct10n, and radiometric br1ghtness temperature for C-130 trans1t V, August 5, 1980.

~ E

i ~ i ~

:;;

c o

100

90

80

10

60

50

40

30

210 r-

~ 180 l­i; g i ~

:;;

80 e

60 .:

40

~ ~

20

-.; <;

€ -20 :;!

~ -40

-60 Q

-80 -80

1503 GMT

~ 1450 GMT

C 130 TranSit 6

Storm center 16° 15' N, 71° 221 W Ih' 2'lOO ml

60 40 -20 0 20 40 60 80 Distance east of storm center, n ml

-

-

-

I I I I I I I I I OOOO~~10--~20---30~--4O~--5O~~6O--~IO---80~--90~~loo

Radial distance from storm center, n mt

220

~ 200

'i! !l jj 180

! ji 160

;; E

j 140

120

Ra<llal dlstince from storm center, n mt

Figure C17.- Flight track, INS wind speed, INS wind direction, and radio­metr~c brightness temperature for C-130 trans~t VI, August 5, 1980.

121

240

220

80 E

60 ~ 200

.: C 130 Departure A ~

~ 40 Storm center 16° 26' N. 71° 49' W ~ Ih = JOOOto 4300 ml 180

~ 20

.., 16J{) GMT ~

'0 ~ :c .c 20 1616 GMT ~ 160

~ j ~

40

" 60 ~ 140 a

80 80 60 40 20 20 40 60 80

Distance east of storm center, n ml 120

100 0 10 20 J{) 40 50 60 70 80 90 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 !!!

70

!!! E

E 60 "'i 60

l ~ 50 ~ 50

g i i

40 ~ V>

40

'" l5

J{) ~ JO

20 20

10 10

70 l60

60

270 50

.c

~ E E

~ :! 40 0 !"

~ 180 -l ~

i5 I ~ g JO i ~

'" ~ 20

090

10

50 70 90 100 20 40 90 100

Radial distance from storm center, n ml Distance from storm center, n ml

F1gure C18.- Fl1ght track, INS w1nd speed, INS w1nd d1rection, radiometric br1ghtness tempe r a tures, rad10meter w1nd speed, and radiometer ra1n rate for C-130 departure A, August 5, 1980.

122

240

220

120 E

100 C-l30 Departure B ~

200

.: 80 Storm center 16° 27' N, 71°53' W 'i! ! (h = 4300 to 6100 m I ~

~ 60 ~ 180

40 " 15 ~

~ 20 r 160 1: g 1637 GMT ~

~ ~ ~ ~ 1630 GMT S!

20 ~ 140 0

40 60

Distance east of storm center, n ml 120

100 0 10 2D 30 40 50 60 70 80 90 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 ~

70

" ~ E

E 60 "i 60

"i ~ ~ 50 ~ 50

~ i i S

40 V> 40

~ ;;: .., JO

Il JO

20 20

10 \0

70 360

60

270 50

~

~ E E

" Jf 40 0 e ~ " 180 § <;

" {; 30

" ~ V>

~ ;;:

20 090

\0

000 0 0 100 0 10 20 JO 40 50 60 7D 80 90 100

Radial distance from storm center, n ml Olstance from storm center, n ml

Fl.gure C19.- Fl1.ght track, INS wl.nd speed, INS wind dl.rection, radiometrl.c brl.ghtness temperatures, radl.ometer wl.nd speed, and radl.ometer rain rate for C-130 departure B, August 5, 1980.

123

124

240

220

120 E

100 C 130 o epa rtu re C ~

80 Storm center 16° 29' N, 71° 58' W

~ Ih = 6100 m I 60

~ 1659 GMT

'" 40 15

~ 200

i! !. e

180 J!l

~ '" 20 ~

~ 1637 GMT

20 C

! ~ e

! 40

60 80 100 120 140 160 180 200 220 120

Distance east of storm center, n ml

100 100 110 200

Radial distance from storm center, n ml

100 100

90 90

80 80

70 ~

70

!( 60 E

e

~ 60

l SO

"!!

~ 'E SO i

i 40 V'>

'!;

J)

J!l 40

~ ~ J)

20 20

10 10

60

270 SO

'" !

E e

~ 0

~ i3

180

'E ji

V'> z

090

ooo~~---L __ ~ __ ~~ __ ~ __ L-~ __ ~~ 100 110 120 130 140 150 160 190 200 110 120 130 140 ISO 160 170 180 200

Radial distance from storm center, n ml Distance from storm center, n ml

F~gure C20.- Fl~ght track, INS w1nd speed, INS w1nd direction, radiometric br1ghtness temperatures, radiometer w1nd speed, and radiometer ra1n rate for C-130 departure C, August 5, 1980.

1~'--'-'--'--r-'r-'--'-'

100 1724 GMT

~.

~ 80

! :: \-__ -"16"'5'-'9 G"'Mc.:T+ ____ ---i

€ 20 g

~ -:;, -10 Q

C 130 Departure 0

Storm center 16° 32' N, 72° 6' W I h = 6100 to 1800 m I

-40 L--'..........J_...L..--'_...L..-"-_"---"

160 180 100 1~ 140 160 180 300 J~

Distance east of storm center, n ml

l00r--'---'--~---.---r---'--'---'---'--'

c o

90

80

70

10

10

170

180 'C

090

Radial distance from storm center, n ml

140 r--,--r--.--.--.--.--,--.... -,---,

m

E 100

~ 1:. ~ 180

lOO~1OO--1~1O--n~0--2L~--1L40--1L~--L--L--L--L--3OO

Radial distance 'rom storm center, n ml

lOOr---r--.--,--~---r---r--.---,--,---,

90

80

1!! 10

E

l 60

];! ~ i

~ 40 ~ ~ '"

10,--.--.--,--,--,--,--,--,--,---.

60

to

Distance from storm center, n ml

F1gure C21.- F11ght track, INS w1nd speed, INS w1nd d1rection, radiometric brightness temperatures, rad10meter wind speed, and rad10meter ra1n rate for C-130 departure 0, August 5, 1980.

125

126

110 E

100

.... 80

~ C-110 Departure E

~ 60 Storm center 16° 34' N, 72° 13' W

Ih=18ootD5IXlml

'" 40 '0

"" 10 t:: g

~ 10 .5

-40 200 210 240 160 280 300 310 340 360

Distance east of storm center, n ml

100

90

80

10

~ 60 E

i 50 g i

40 ~

~

30

10

210

! ~ 0

~ "

180

2! i

V>

~

0\10

Radial distance from storm center, n ml

F1gure C22.- F11ght track, INS wind speed, and INS wind direction for C-130 departure E, August 5, 1980.

80 80 Z251 GMT E E

60 60 ~.

40 2143G/1

..,. 40

~ ~ ~

20 2150 GMT 20

~ "0 P-3TranSIt 1 "0 P 3Transit 2

~ -20

Storm center 24° 20' N, 92° 38' W ~ -20

Storm center 24° 24' Nt 92° 38' W t: g ~ -40 (h= 1500mi -4{) (h = 1500 ml

~ ~ 60 ~ 60 C; C; 80 -80 80 80 80

Distance east of storm center, n ml Distance east 01 Siorm center, n ml

100 100

9() 9()

80 80

10 10

~ 60 ~ 60 E e

"2 l 50 ~ 50 ];! 1! i • 40 40

'" '" ~ ~

JI 30

20 20

10 10

360 I I I I I I I I I 360

210 f- - 210

! !

f 180 f-iO

" 0

~ 180 iO -];! i

];! i

~ '" ~

1l9Or- - 090

Distance from storm center, n ml Distance from storm center, n ml

F~gure C23.- Fl~ght track, INS wind speed, and INS wind d~rect1on for P-3 transits I and II, August 8, 1980.

127

128

80 E

60 P-3 TranSit 3

~~ 40 Storm center 24° 25' W, rnO 51' W (h=l500m)

~ 20

2319 GMT

'0 2339 GMT

'" 20 ---...,;: 1: g

~ -40

-60 <5

-80 80

Distance east of storm center, n m.

100

90

80

70

~ 60 E

i 50

~ i ~

40 ~

II

20

10

l60

270

r ~ 0

~ ;; 180 ~ i ~

~

090

10 20 30 40 50 60 n Distance from storm center, n mt

F1gure C24.- F11ght track, INS W1nd speed, and INS W1nd d1rect1on for P-3 trans1t III, August 8, 1980.

100

90

110

10

~ 60 E

l 50

>! i

40 ~

~

JO

20

10

16O

270

~

" 0

~ -c 1l1li

-g i ~

~

120r=-__ _

1701 GMT 1640 GMT .:-~ 100

l1li

601--------4-------1

40

20 C lJO Approach A

Storm center ZJ" 55' N, 910 27' W Ih = 4600 to 5900ml

Distance east of storm center, n ml

Radial distance from storm center, n ml

~

~

l >! i ~

~

~ §.-

~ -c -g i ~ z

E

.:-

~ ~ '" '0 ~

t: !!

~ '" 05

100

90

110

70

60

50

40

JO

20

10

270

1l1li

090

140

120

100

l1li

60

40 C 130 Approach B

20 Storm center 23° 58' N .. 91° 33' W Ih=5900ml

-20L-J--L~ __ ~_L~ __ ~

J60 J80 400 420 440 460 4l1li 500 520

Distance east 01 storm center, n ml

oooL-~ __ ~ __ ~~L__L __ ~ __ L_~ __ _L ___

400 410 420 410 440 450 460 470 480 490 500

Rachal distance from storm center, n ml

F1gure C25.- F11ght track, INS w1nd speed, and INS W1nd direct10n for C-130 approaches A and B, August 8, 1980.

129

130

240

220

140 E

120 ~

200 - 1729GMT

~ ~ 100

~ 1751 GMT ~ 8D $ 1110

~ 60 " "0 .c .c 40 ~ 160 1:: g C 130 Approach C

~

~ 20 Storm center 24° l' N 91° 39' W E

Ih=59OOml " ~ 140 .5

20 260 280 300 420

Distance east of storm center, n ml 120 r;: :j7;;!J ~

100 300 400

Radial distance from storm center, n ml

100 100

90 90

80 110

70 ~

70

~ E

E 60 "i 60

l ~ 50 "l! 50

~ i i

40 ~ 40 V>

:!O ~

30 '" JO

20 20 ff 10 10

0 300 JIO 400

Distance from storm center n ml

360 I I I I I I I I I

270 f- -

l " 0

~ ISO f-Computed rain rate of zero bebYeen 363 and 397 n rnl -

i3

" i V> z

D90 - -

I I I I I ILl I OOD3OO~--J~IO---~~0---J3O~--J40~--~~0---J6D~--J~70---3W~--J90~~4OD

Radial distance from storm center, n rnl

F1gure C26.- F11ght track, INS wind speed, INS w1nd d1rect10n, rad1o­metr1c br1ghtness temperatures, rad10meter wind speed, and rad10meter ra1n rate for C-130 approach C, August 8, 1980.

240

220

140 E

120 200

f 100 1151 GMT

~ 80

/" 60

'0

" ~ ~

180 J'l

c ~

~ 40 1: g 1817 GMT

~

160 ~

20 C 130 Approach 0

~ Storm center 2l4' N, 91° 46' W <'5 Ih=58ooml

J'l ~

! 140

20 160 180 20D 220 240 260 280 JOD 320

Distance east of storm center, n ml 120

100 200 300

Radial distance from storm center, n ml

100 100

90 90

80 80

10 ~

10

~ 60 E E -oj 60

l 50 ~ 2! 50 ~

" ~ 40 V> ;;:

30

J'l 40 ~ ~ 30

20 20

10 10

JOD

Distance from storm center n rnl

210

~

" 0

~ 180 <3 Computeo rain rate of zero between 200 and 285 n m, c

" V> z

090

Radial distance from storm center, n rnl

F1gure C27.- F11ght track, INS w1nd speed, INS w1nd d1rect10n, rad10-metr1c br1ghtness temperatures, radiometer w1nd speed, and rad10meter ra1n rate for C-130 approach D, August 8, 1980.

131

132

140

120

100 E

80 200

.: C 130 Approach E

~ 60 Storm center 24° 7' N, 91° 53' W

Ih=58ooml

~ 40

1817 GMT 10

~

~ ~ E

180 ., c

'0

'" '/ ~

'" ~ 160

~ 10

40 1845 GMT C;

-;; E

~ 60

60 80 100 110 140 160 180 100 120

Distance east of storm center, n ml

200

Radial distance from storm center, n rnl

100 100

90 90

80 80

70 ~

70

~ 60 E

i 50

E ~ 60

~ g 50 i g

i 40 V> z 1 40

~

20

10

'()()

60

270 50

'" E ~ E

40 c 0 ~

~ c

180 ~ -c c JO i ~

V> ~ z

090

000lLoo~~--~--~---L---L---L---L---L---L--~1oo 200

Radial distance from storm center, n mt Distance from storm center, n mt

F1gure C28.- F11ght track, INS w1nd speed, INS w1nd d1rection, rad10-metr1c br1ghtness temperatures, rad10meter w1nd speed, and rad10meter ra1n rate for C-130 approach E, August 8, 1980.

240

220

100 E

80 200 .: C 130 Approach F

~

~ 60 Storm center 24° 9' N, 91° 57' W ~

:!l 40 I h = 5700 to 3700 m I E

~ .., 180

20 ! "5 .c

i ~ 160

-20 ~

~ 1845 GMT E

40 '!/ ~ 140 c; 1850 GMT

I:. -60

60 80 100 220

Distance east of storm center, n 120

ml

100 0 100

Radial distance from storm center, n ml

100 100

90 90

80 80

70 ~

70

~ E E 60 of 60

l ~ 50 ~ 50

~ iii

i 40

.., 40 ~ ~ :!O

" JO

I:. JO

20 20

10 10

70 360 I I I I I I I I I

60

270 I- - 50

.c

g' E E

40 c

~ ~ l- \,. c

" 180 l'

c 30 iii ~ ~ z ~

20 090 I- -

10

000 I I I I I I I I I

0 10 20 30 40 50 60 70 80 90 100

Radial distance from storm center, n ml Distance from storm center, n ml

Flgure C29.- Flight track, INS wind speed, INS wlnd dlrection, radl0-metrlc brlghtness temperatures, radlometer wind speed, and radlometer raln rate for C-130 approach F, August 8, 1980.

133

134

240 I I I I I I I I I

220 - -80

E 60 ~ .. 200 - -

C-llOTranSit I ~.

40 Storm center 24° 14' N, 92° 14' W ~

~ Ih=JlOOml 1:-E -

~ 20 J!l ISO -

1954 GMT ~ c '0 1957 GMT

~

~ 20 ~ 160 f- -

~ J!l

~ 40 ~ 60 ~ 140 -

Q

SO -SO -60 40 20 20 40 60 SO II

120 ~ -Distance east of storm center, n ml

I I I I I I I I I 100

50 70 SO 90 100 0 10 20 lO 40 60

Radial distance from storfT1 center, n ml

100 100

90 90

8U SO

70 i!( 70

i!( E

E 60 "i 60

"i ~

~ 50 -g 50 i

-g i

40 ~ 40

"' a ~ ~

:~ '" 3D

10

70 360

60

270 50

! ~

E 40 c E

-g E ;; ~

~ ~ lO :< "'

J!l z ~

~ 20 090

100

Radial distance from storm center. n ml Distance from storm center, n ml

F~gure C30.- Fl~ght track, INS wind speed, INS w~nd d~rect~on, rad~o­

metr~c brightness temperatures, rad~ometer w~nd speed, and rad~ometer ra~n rate for C-130 transit I, August 8, 1980.

240

2ZO

160 E

140 C 130 Departure A 200 ~.

120 Storm center 2l26' N 92° 52' W

~ Ih=3600to5600ml

~ 100 2350 GMT

80 '0

~ '" 60 t g

~

~ ~

180 $

! ii 160

~ 40

20 2330 GMT 0

.,. ~ ~ 140

160

120 Distance east of storm center, n ml

1000 100

Radial distance from storm center n ml

100 100

90 90

80 80

10 i!!

10

i!! 60 E E 1i 60

l 50

1!

~ 1! 50 i

i 40

'" ~ ~ 40 !5 -0

30 i:. 30

20 20

10 10

10

60

210 50

'" l

E E

40 " 5! ~

~ 180 -0

" ~ 1! i ~

30

'" z ~ 20

090

10

Radial distance from storm center, n ml Distance from storm center, n rnl

F1gure C31.- Flight track, INS w1nd speed, INS w1nd d1rect1on, radio­metr1c brightness temperatures, radiometer wind speed, and rad10meter ra1n rate for C-130 departure A, August 8, 1980.

135

136

220,-,----,-,----,-,---,--,------,

100

1" 180 2414 GMT

~ 160

•. 1401---------7'-+-----------1

'" 120 g

~ 100 2350 GMT

_. 80 Storm center 24° 27' N, 92° 53' W

C 130 Departure B

a (h= 5600 to 6800 m) 60 L--"-________________ --'

o 20 40 60 80 100 120 140 160

Distance east 01 storm center, n ml

100,--,---,--,---,--,---,--,--,---,-----,

90

SO

70

i!( E 60

I 50 g

~ 40 z

30

20

lO

270

~L--L---I ~~J 100 llO 120 130 140 150 160 170 180 19() 100

Radial distance from storm center, n ml

220

loo~ __ ~ __ ~_L__L__L_ __ L_ __ L_ __ L_ __ L___J

100 llO 120 130 140 150 160 170 ISO 190 100

Radial distance from storm center, n ml

loor--or--.---,---,---,---r--.---,---,-----,

9()

80

!!l 70

E

I 60

g 50 'i

1 40

~

70,-----,,--,---,---,---,---r--.---,---,-----,

60

50

20

lO

llO 120 130 140 150 160 170 19IJ 100

Distance from storm center, n ml

F1gure C32.- F11ght track, INS W1nd speed, INS w1nd d1rect10n, rad10-metr1c br1ghtness temperatures, rad10meter w1nd speed, and rad10meter ra1n rate for C-130 departure B, August 8, 1980.

240

220

JOO E

280 200 ~

2439 GMT ~

~ 260 1<i

~

~ 240 2 1110

220 c '0 ~

~ 200 ~ 160 t: g 2414 GMT

180 ;;

~ E

160 j 140 C;

140 40 60 80 100 120 140 160 180 200

Distance east of storm center, n ml

100 200 JOO

Radial distance from storm center, n ml

100 100

90 90

110 110

70 !!i

70

!!i 60 E E

"'i 60

"'i ~ ~ 50 ];!

~ 50 i

i 40

z ~ 40 ~

" JO ~

20

10

60

270 50 L'

E

*' E

2 40 c 0 ~

~ 1110 c ~

];! .;; JO i ~ ~ " z ~

20 090

10

JOO 0

JOO 200

Radial distance from storm center, n m' Distance from storm center, n rnl

F1gure C33.- F11ght track, INS w1nd speed, INS wind direct10n, rad10-metr1c br1ghtness temperatures, rad10meter wind speed, and rad10meter ra1n rate for C-130 departure C, August 8, 1980.

137

138

320 E

) 2449 GMT JOO

~~ 280

~ 260 2439 GMT

240 <;

'" 220 1:: C 130 Departure D g

~ 200 Storm center 2l31' N, 92° 53 W

in=6200tOl9ODml 180

c; 160

40 60 80 100 120 140 160 180 200

Distance east of storm center, n ml

100

90

80

70

!i 60 E "i ~ 50

2' i

40 ~

~

JO

20

10

J60

270

! c 0

~ 180 ;; c , ~ z

O9Or

Radial distance from storm center, n ml

F1gure C34.- F11ght track, INS wind speed, and INS w1nd direction for C-130 departure D, August 8, 1980.

I 2 Government Accession No 1 Report No NASA TM-86390

4 Title and Subtitle

Act1ve and PaSS1ve M1crowave Measurements 1n Hurr1cane Allen

7 Authorls) V1ctor E. Delnore, G1lbert S. Bahn, W1111am L. Grantham, R1chard F. Harr1ngton, and W. Llnwood Jones

3

5

6

8

10

ReciPient's Catalog No

Repon Date November 1985 Performing OrganlZltlon Code

506-58-23-01

Performing Organization Report No L-15775

Work Unit No 9 Performing Organization Name and Address

NASA Langley Research Center Hampton, VA 23665-5225

11 Contract or Grant No

12 Sponsoring Agency Name and Address 13 Type of Repon and Period Covered

Technical Memorandum Nat10nal Aeronauticg and Space Adm1n1stratlon Washlngton, DC 20546-0001

14 Sponsoring Agency Code

15 Supplementary Notes The Hurr1cane Allen data are ava1lable on magnet1c tape as a supplement to

th1s report. Vlctor E. Delnore and G1lbert S. Bahn: PRC Kentron, Inc., Hampton, Virg1n1a. W11l1am L. Grantham and Rlchard F. Harr1ngton: Langley Research Center,

Hampton, V1rg1n1a. W. Llnwood Jones: Harr1S Corp., Melbourne, Flor1da.

16 Abstract

17

19

Th1S report summar1zes the NASA Langley Research Center analys1s of the a1rborne m1crowave remote senslng meagurements of Hurr1cane Allen obta1ned on August 5 and 8, 1980. The 1nstruments were the C-band stepped frequency mlcrowave rad10meter and the Ku-band a1rborne m1crowave scatterometer. They were carried aboard a NOAA a1rcraft mak1ng storm penetrat10ns at an altltude of 3000 m and are sensitive to ra1n rate, surface w1nd speed, and surface w1nd vector. The w1nd speed lS calculated from the 1ncrease 1n antenna br1ghtness temperature above the egtlmated calm-sea value. The ra1n rate lS obta1ned from the d1fference between antenna temperature lncreases measured at two frequencles, and wlnd vector lS determ1ned from the sea-surface normal1zed radar cross sectl0n measured at several aZ1muths.

Compar1son w1nd data were prov1ded from the inert1al navlgatlon systems aboard both the C-130 a1rcraft at 3000 m and a second NOAA alrcraft (a p-3) operatlng between 500 and 1500 m. Comparlson ra1n rate data were obtalned wlth a ra1n radar aboard the P-3. Evaluatlon of the surface w1nds obta1ned with the two m1crowave 1nstruments was 11mlted to compar1sons wlth each other and W1th the fllght-Ievel winds.

Two 1mportant conclUS1ons are drawn from these comparisons: (1) the rad10meter 1S accurate when pred1ct1ng fl1ght-Ievel w1nd speeds and ra1n rate and (2) the scatter­ometer produces well-behaved and cons1stent w1nd vectors for the raln-free perl0ds.

Key Words (Suggested by Author(s)) 18 Distribution Statement Remote sens1ng Unclasslfled - Unl1mlted M1crowave technology Hurr1cane reconnalssance Rad10meter Scatterometer SubJect Category 43

Security Oasslf lof thiS report) 20 Security ClaSSlf lof thiS page) 21 No of Pages 22 Price Unclass1f1ed Unclasslf1ed 145 A07

For sale by the National Technical Information SerVice, Springfield, Virginia 22161 NASA Langley, 1985

End of Document