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Results from Winter Storm Reconnaissance Program 2007

Yucheng Song IMSG/EMC/NCEPZoltan Toth EMC/NCEP/NWS Sharan Majumdar Univ. of MiamiMark Shirley NCO/NCEP/NWS

http://www.emc.ncep.noaa.gov/gmb/targobs

Meeting of the Working Group on Space-based Lidar Winds, Monterey, CA 5-8 Feburary 2008

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Winter Storm Damages can’t be underestimated

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Acknowledgments

• NWS field offices, HPC/NCEP and SDMs• NOAA G-IV and the USAFR C-130 flight crews• CARCAH (John Pavone)• Jack Woollen - EMC• Russ Treadon - EMC• Mark Iredell - EMC• Istvan Szunyogh – Univ. of Maryland• Craig Bishop - NRL• + others who have contributed!

Winter Storm Reconnaissance Program

Objective:

Improve Forecasts of Significant Winter Weather Events Through Targeted Observations in Data Sparse Northeast Pacific Ocean

Adaptive approach to collection of observational data:1) Only Prior to Significant Winter Weather Events of Interest2) Only in Areas that Influence high impact event Forecasts

Results: 70+% of Targeted Numerical Weather Predictions Improve

10-20% error reduction for high impact event forecasts12-hour gain in predicting high impact events – earlier warnings possible

Operational since January 2001

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About the Winter Storm Reconnaissance (WSR 2007) Program

• Took place 20 Jan – 13 March 2007• Dropwinsonde observations taken over the NE

Pacific by aircraft operated by NOAA’s Aircraft Operations Center (G-IV) and the US Air Force Reserve (C-130s).

• Observations are adaptive – – collected only prior to significant winter weather events of

interest – in areas that might influence forecast the most.

• 31 flights, around 478 dropsondes this winter which is increased from 342 drops last year

• Several communication problems from C-130s

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About the Winter Storm Reconnaissance (WSR 2007) Program – (continued)

• Evaluation methods– NCEP Global Forecast System running on T126L28

resolution – Three sets of experiments

• A. GFS run with all the WSR dropsondes being assimilated

• B. GFS run without WSR dropsondes data rejected on all days

• C. GFS run with WSR dropsondes data rejected only on the WSR observation day (i.e. the guess files are the same as the operational)

• Experiment Design - Experiment C is used for signal propagation studies, it can single

out the data impact due to current dropsondes clearly without interferences from the previous dropsondes

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The ETKF spotted the target area

Expected error reduction propagation

Targeting methods – ETKF application example

Storm

Dropsondes to be made by G-IV

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Forecast verification(Jan 20-22,2007 A vs.C)

Red contours show forecast improvement due to WSR dropsondes, blue contours show forecast degradation

500mb height

250mb height

Sea Level Pressure

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Impact of Dropsondes

500mb height250mb height

Precipitation Surface pressure

Contours are 1000mb geopotential height, shades are differences in the fields between two experiments

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Comparison of ETKF signal and NCEP signal(A vs. C)

The ETKF signal The NCEP signal

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Valentine’s day storm2007

One of the largest winter storms that strikes interior sections of the Northeast since 1950

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NCEP requested two missions

• A flight is requested from Honolulu along track 34 with a control time of 11/00Z Verification information is as follows:

Verification time: 2007021400 Latitude: 36 Longitude: 86 Priority: HIGH Comments: East Coast winter Wx • A flight is requested from Honolulu along track 46 with a

control time of 12/00Z Verification information is as follows:

Verification time: 2007021412 Latitude: 38 Longitude: 77 Priority: HIGH Comments: East Coast winter wx

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Comparison of ETKF signal and NCEP signal

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Valentine’s day Storm

• Weather event with a large societal impact• Each GFS run verified against its own analysis – 60 hr forecast• Impact on surface pressure verification• RMS error improvement: 19.7% (2.48mb vs. 2.97mb)

Surface pressure from analysis (hPa; solid contours)Forecast Improvement (hPa; shown in red)Forecast Degradation (hPa; blue)

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Valentine’s day Storm

• Weather event with a large societal impact• Each GFS run verified against its own analysis – 60 hr forecast• Impact on surface pressure verification• RMS error improvement: 19.7% (2.48mb vs. 2.97mb)

Surface pressure from analysis (hPa; solid contours)Forecast Improvement (hPa; shown in red)Forecast Degradation (hPa; blue)

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Valentine’s day StormImpact on precipitation (A.vs.C)

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Forecast Verification for Wind (2007)

RMS error reduction vs. forecast lead time

10-20% rms error reduction in winds

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Forecast Verification for Temperature (2007)

RMS error reduction vs. forecast lead time

10-20% rms error reduction in Temperature

60 hr forecast is equivalent to 48hr forecast

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Breakdown for cases

Variable# cases

improved# cases neutral

#cases degraded

Surface pressure 25 0 12

Temperature 24 0 13

Vector Wind 27 0 10

Humidity 24 0 13

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Individual Case Comparison

1 denotes positive effect

0 denotes neutral effect

-1 denotes negative effect

26 OVERALL POSITIVE

0 OVERALL NEUTRAL

11 OVERALL NEGATIVE

70% improved 30 % degraded

VR OBSDATE P T V OVERALL REGION FHOUR AK 20070120 1 1 1 1 130W ,55N 48 C 20070128 1 -1 -1 -1 97W ,33N 72 W 20070207 1 -1 -1 -1 123W ,40N 48 W 20070208 -1 1 1 1 123W ,40N 24 W 20070209 1 1 1 1 122W ,38N 24 W 20070211 1 -1 1 1 110W ,32N 48 E 20070211 1 -1 -1 -1 86W ,36N 72 W 20070212 -1 -1 -1 -1 110W ,32N 36 E 20070212 1 1 1 1 77W ,38N 60 W 20070215 1 -1 1 1 120W ,45N 24 AK 20070216 1 -1 1 1 135W ,60N 48 W 20070217 1 1 1 1 124W ,40N 36 W 20070218 1 1 1 1 117W ,40N 24 C 20070218 1 1 1 1 108W ,37N 48 C 20070218 1 1 1 1 90W ,35N 72 W 20070220 1 1 1 1 122W ,40N 60 W 20070221 1 1 1 1 122W ,40N 36 C 20070221 1 -1 -1 -1 96W ,43N 72 C 20070221 1 1 1 1 93W ,40N 96 W 20070222 1 1 1 1 120W ,37N 24 C 20070222 -1 -1 -1 -1 90W ,40N 72 E 20070222 -1 1 1 1 80W ,36N 96 W 20070223 1 1 1 1 123W ,42N 48 C 20070223 1 -1 1 1 94W ,37N 48 W 20070225 -1 1 1 1 123W ,42N 48 W 20070226 1 1 1 1 123W ,42N 24 W 20070228 1 1 1 1 122W ,43N 36 E 20070228 -1 1 1 1 86W ,35N 48 W 20070302 1 1 1 1 125W ,49N 36 AK 20070306 -1 -1 -1 -1 130W ,55N 36 E 20070308 1 1 1 1 85W ,34N 108 W 20070308 -1 1 -1 -1 124W ,46N 60 W 20070309 1 -1 1 1 124W ,45N 72 C 20070310 -1 -1 1 -1 93W ,37N 48 C 20070311 -1 1 -1 -1 96W ,32N 36 E 20070311 -1 1 -1 -1 81W ,42N 96 E 20070313 -1 1 1 1 81W ,42N 48

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Overall results for Surface pressure

Of all cases:25 improved 0 neutral12 degraded

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Overall results for Temperature

Of all cases:24 improved 0 neutral13 degraded

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Overall results for Vector wind

Of all cases:27 improved 0 neutral10 degraded

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Overall results for Humidity

Of all cases:24 improved 0 neutral13 degraded

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WSR Summary statistics (2004-2007)

Variable# cases

improved# cases neutral

#cases degraded

Surface pressure 21+20+13+25=79 0+1+0+0=1 14+9+14+12=49

Temperature 24+22+17+24=87 1+1+0+0=2 10+7+10+13=40

Vector Wind 23+19+21+27=90 1+0+0+0=1 11+11+6+10=38

Humidity 22+19+13+24=78 0+0+0+0=0 13+11+14+13=51

25+22+19+26 = 92 OVERALL POSITIVE CASES.

0+1+0 +0 = 1 OVERALL NEUTRAL CASES.

10+7+8 +11 = 36 OVERALL NEGATIVE CASES. 71.3% improved 27.9% degraded

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WSR 2008

• More ensemble members, efficient ET KF codes• No G-IV due to new instrument installation• New tracks for NOAA P-3 flying out of Portland,

OR

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• Background Slides

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Composite summary maps

139.6W 59.8N 36hrs (7 cases) - 1422km 92W 38.6N 60hrs (5 cases)- 4064km

122W 37.5N 49.5hrs (8 cases) - 2034km 80W 38.6N 63.5hrs (8 cases) - 5143km

Verification Region

Verification Region

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3 649.5

60

63.5

0

1000

2000

3000

4000

5000

6000

0 20 40 60 80F o r e c a s t H o u r s

D i s t a n c e ( k m )

ETKF predicted signal propagation

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Precipitation verification

• Precipitation verification is still in a testing stage due to the lack of station observation data in some regions.

20.4416.50OPR

18.5616.35CTL

3:14:1Positive vs. negative

cases

10mm 5mm ETS