Airborne Surface Water & Ocean Topography Mapping System Jim Carswell and Delwyn Moller Remote Sensing Solution, Barnstable, MA Email: [email protected]

Airborne Surface Water & Ocean Topography Mapping System

Airborne Surface Water & Ocean Topography Mapping System

Jim Carswell and Delwyn MollerRemote Sensing Solution, Barnstable, MA

Email: [email protected]

Jim Carswell and Delwyn MollerRemote Sensing Solution, Barnstable, MA

Email: [email protected]

2011 Interdepartmental Hurricane Conference – Miami, FL2011 Interdepartmental Hurricane Conference – Miami, FL11

Small Scale Variability unresolved by Small Scale Variability unresolved by Nadir Altimetry ObservationsNadir Altimetry Observations


100 km100 km scale eddies 10 km scale eddies10 km scale eddies

Ground tracks of Jason (thick) and T/P (thin) Tandem Mission

Current Altimetry Limitations Current Altimetry Limitations


(ECCO-2 MIT JPL ocean current model )

Estimating the Circulation and Climate of the Ocean

ECCO-2: Menemenus et al., EOS 2005

Satellite altimetry data have significantly advanced our knowledge of the dynamics of the ocean variability, but due to resolution and coverage constraints …

•Cannot resolve features under 100 km resolution.

•Most of the ocean’s kinetic energy are at scales under 100 km.

•An example is the Gulf stream.

• Smaller scale processes, under 100 km, may hold the key to understanding the evolution of oceanic kinetic energy & its implications on biochemistry.

Global ocean topography observations at kilometer resolution and centimeter accuracy are needed.

Hydrology Problems / Open QuestionsHydrology Problems / Open Questions


Knowledge of the spatial and temporal distribution of surface waters is poor:

– Lakes, reservoirs wetlands, etc are globally distributed but not measured.

– Under-developed economic and political infrastructures and/or remoteness prevent measurement of these features.

Hydrologic Science and Applications Issues:

– Need to constrain water and energy cycle models with surface water discharge and storage changes, globally & consistently

– Improve understanding of flow hydraulics, especially for flood hazards

– Trans-boundary water flows are poorly known but critical for water resource management

SWOT MissionSWOT Mission


Oceanographic ObjectivesOceanographic Objectives::

•To characterize the ocean mesoscale and To characterize the ocean mesoscale and submesoscale circulations at spatial resolutions of submesoscale circulations at spatial resolutions of 10 km and larger. 10 km and larger.

Hydrologic ObjectivesHydrologic Objectives::

•To measure the storage change in lakes, To measure the storage change in lakes, reservoirs, and wetlands larger than 250m by reservoirs, and wetlands larger than 250m by 250m and to estimate discharge in rivers wider 250m and to estimate discharge in rivers wider than 100 m (50 m goal) at sub-monthly, seasonal, than 100 m (50 m goal) at sub-monthly, seasonal, and annual time scales.and annual time scales.

SWOT KARINSWOT KARIN


SWOT KARIN•Ka-band SAR Interferometer.•2 swaths, 60 km each.

•Produces heights and co-registered “all-weather” imagery.

•Additional instruments:– Conventional Jason-class altimeter for

nadir coverage.– AMR-class radiometer (with possible

high frequency band augmentation) to correct for wet-tropospheric delay.

•No land data compression onboard (50m resolution).

•Onboard data compression over the open ocean (1km resolution) at centimeter topography resoltuion.

Cross Track Radar InterferometryCross Track Radar Interferometry

• Complex images simultaneously Complex images simultaneously formed using two receive antennas formed using two receive antennas with cross track baseline, B. with cross track baseline, B.

• Pixel phase difference between two Pixel phase difference between two complex images is related to the complex images is related to the path difference (path difference (r): r): 22r / r / 22B sin(B sin())• Incidence angle, Incidence angle, is determined from is determined from

phase difference, phase difference, ..• Elevation (Elevation (h) is then determined:h) is then determined: h = H – R sin(h = H – R sin()) where R is measured by the radar & H where R is measured by the radar & H is the altitude of the platform.is the altitude of the platform.• Ka-band Interferometry is making Ka-band Interferometry is making

centimetric resolution possible.centimetric resolution possible.

• Unlike a conventional radar (SAR) which provides a flat image, interferometric radar (InSAR) systems provide pixel elevation through triangulation (i.e. 3D image of scene).

Cross track DistanceCross track Distance


KaSPARKaSPAR


(Courtesy of Carrie Rhoades, NASA Dryden.)

KaSPAR – SWOT Cal/Val Configuration•Flat panel low profile design compatible with Flat panel low profile design compatible with multiple aircraft.multiple aircraft.

•Solid-state, conduction cooled design enable Solid-state, conduction cooled design enable operation unpressured up to 70 kft.operation unpressured up to 70 kft.

•SolidWorks design shows KaSPAR installed SolidWorks design shows KaSPAR installed in King Air instrument bay.in King Air instrument bay.

•Current NASA aircraft: NASA King Air, Current NASA aircraft: NASA King Air, Global Hawk (aft port), and Ikhana (nose).Global Hawk (aft port), and Ikhana (nose).

•Multi-baseline along and cross track to Multi-baseline along and cross track to support SWOT studies and provide phase support SWOT studies and provide phase unwrapping.unwrapping.

•Modular design can deploy single baseline Modular design can deploy single baseline configurations for reduced size.configurations for reduced size.

•Low CTE Panel provides rigid design to Low CTE Panel provides rigid design to prevent deflections and has several mounting prevent deflections and has several mounting configurations. configurations.

Dimensions in inches.

74 cm

60 cm

KaSPAR installation on NASA Dryden King Air(SolidWorks 3D Model)

KaSPAR Installation Locations

KaSPAR PerformanceKaSPAR Performance


KaSPAR Performance / Measurements:KaSPAR Performance / Measurements:•Single-pass, multi-baseline cross and along Single-pass, multi-baseline cross and along track InSAR.track InSAR.

•Compact, solid-state, conduction cooled Ka-Compact, solid-state, conduction cooled Ka-band design enabling high altitude operation.band design enabling high altitude operation.

•Maps wetlands, river and ocean topology Maps wetlands, river and ocean topology (cross track baselines), velocity (along track (cross track baselines), velocity (along track baselines) intensity.baselines) intensity.

•Novel internal calibration measures system Novel internal calibration measures system magnitude and phase drifts to better than 0.01 magnitude and phase drifts to better than 0.01 dB and 0.006 degrees, respectively.dB and 0.006 degrees, respectively.

•Capable of high altitude (>70 kft) deployment.Capable of high altitude (>70 kft) deployment.

•Also applicable to terrestrial mapping.Also applicable to terrestrial mapping.

ParameterParameter ValueValue UnitUnit

Center Frequency 35.75 GHz

Peak Transmit Power 40 W

Platform Height 35/70 kft

Swath1 5/10 km

Bandwidth 80 to 4502 MHz

Mean height error3 1.2 to 2.1 cm

Radial velocity error 10 cm/s

Incidence angles4 0 to 27 deg

1: Inner and outer swath, assumes 6 m/s wind speed – limits outer angle.2: Inner region of swath sample at 450 MHz.3: 80 m azimuth, 20/50 m (inner/outer) range posting.4: Higher winds speeds or NRCS would extend outer angle.

Science and Operational ApplicationsScience and Operational Applications


• Weather reconnaissance (storm surge prior to Weather reconnaissance (storm surge prior to landfall).landfall).

• Search and rescue.Search and rescue.

• Flood mapping / damage assessment.Flood mapping / damage assessment.

• Sea ice/Freeboard mapping.Sea ice/Freeboard mapping.

• Estuarine environments and dynamics.Estuarine environments and dynamics.

• Flooding dynamics and flood plain mappingFlooding dynamics and flood plain mapping

• Ice-covered lakes or rivers including of ice-Ice-covered lakes or rivers including of ice-breakup.breakup.

• Pollutant transportation and imaging.Pollutant transportation and imaging.

Google Maps GLISTIN Radar 3D Imagery (fast product)

GLISTIN Measurements - Gulfstream IIIGLISTIN Measurements - Gulfstream III

RSS & JPL GLISTIN/IPY Project

GLISTIN Radar 2D Imagery (fast product)


RSS Ka-band Elevation Mapper on the NASA RSS Ka-band Elevation Mapper on the NASA Gulf Stream Ka-band InSARGulf Stream Ka-band InSAR

Images were generated from data collected on Images were generated from data collected on the second Ka-band engineering test flight on the second Ka-band engineering test flight on March 16, 2009. Aircraft flew on a heading of March 16, 2009. Aircraft flew on a heading of 180° and imaged from San Dimas, CA to Irvine, 180° and imaged from San Dimas, CA to Irvine, CA at an altitude of 6000 m. The data was CA at an altitude of 6000 m. The data was processed to a height map with posting of 3 processed to a height map with posting of 3 meters; with height accuracies as good as 30 cm meters; with height accuracies as good as 30 cm in the near range.in the near range.

15

km

Reflector deployment at Greenland’s Summit (NSF) and a field-processed “quick-look” Ka-band backscatter imagery over Jakobshavn glacier collected 5/6/09. Six data flights occurred in Greenland including a transect from Summit to the coast and detailed mappingmapping over Jakobshavn glacier. Repeat observation after 6 days reveal 1km horizontal movement.

Ka-band InSAR on Gulfstream III

• RSS and Jet Propulsion Laboratory (JPL) Project.RSS and Jet Propulsion Laboratory (JPL) Project.• Ka-band InSAR integrated into NASA UAV SAR. Ka-band InSAR integrated into NASA UAV SAR. • Demonstrate single pass elevation mapping with a Demonstrate single pass elevation mapping with a

Ka-band InSAR. Ka-band InSAR. • Several missions executed in May 2009 over Several missions executed in May 2009 over

Greenland, current funding to further analyze Greenland, current funding to further analyze measurements and 2010/11 funding likely to convert measurements and 2010/11 funding likely to convert prototype system to operations. prototype system to operations.

• Technology / experience transfer to KaSPAR.Technology / experience transfer to KaSPAR.


RSS – JPL GLISTIN Initial ResultsRSS – JPL GLISTIN Initial Results

• GLISTIN Image of Greenland Coastline:• Intensity 2D image.• 3D elevation map (800 m

scale).• Correlation between elevation

and digital map.• Error image (10 cm for high

SNR).• First ever single pass Ka-band

cross track interferometric elevation measurements.

• Met goal to achieve 10 cm height measurement.

• Most difficult case.• 7.5 km square


Documents

Airborne Surface Water & Ocean Topography Mapping System Jim Carswell and Delwyn Moller Remote Sensing Solution, Barnstable, MA Email: [email protected]