Airborne Surface Water & Ocean Topography Mapping System

1. Airborne Surface Water & Ocean Topography Mapping System Jim Carswell and Delwyn Moller Remote Sensing Solution, Barnstable, MA Email: carswell@remotesensingsolutions.com 2011 Interdepartmental Hurricane Conference – Miami, FL

2. Small Scale Variability unresolved by Nadir Altimetry Observations Ground tracks of Jason (thick) and T/P (thin) Tandem Mission 10 km scale eddies 100 km scale eddies 100 km 2011 Interdepartmental Hurricane Conference – Miami, FL

3. Current Altimetry Limitations Estimating the Circulation and Climate of the Ocean (ECCO-2 MIT JPL ocean current model ) • 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. ECCO-2: Menemenus et al., EOS 2005 • 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. 2011 Interdepartmental Hurricane Conference – Miami, FL

4. Hydrology Problems / Open Questions • Knowledge of the spatial and temporal distribution of surface waters is poor: • Lakes, reservoirs wetlands, etcare 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 2011 Interdepartmental Hurricane Conference – Miami, FL

5. SWOT Mission Oceanographic Objectives: • To characterize the ocean mesoscale and submesoscale circulations at spatial resolutions of 10 km and larger. Hydrologic Objectives: • To measure the storage change in lakes, reservoirs, and wetlands larger than 250m by 250m and to estimate discharge in rivers wider than 100 m (50 m goal) at sub-monthly, seasonal, and annual time scales. 2011 Interdepartmental Hurricane Conference – Miami, FL

6. SWOT 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. 2011 Interdepartmental Hurricane Conference – Miami, FL

7. Cross Track Radar Interferometry • 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). • Complex images simultaneously formed using two receive antennas with cross track baseline, B. • Pixel phase difference between two • complex images is related to the • path difference (Dr): • F = 2pDr / l = 2pB sin(q) • Incidence angle, q, is determined from phase difference, F. • Elevation (Dh) is then determined: • Dh = H – R sin(q) • where R is measured by the radar & H • is the altitude of the platform. • Ka-band Interferometry is making centimetric resolution possible. Cross track Distance 2011 Interdepartmental Hurricane Conference – Miami, FL

8. KaSPAR KaSPAR installation on NASA Dryden King Air (SolidWorks 3D Model) • KaSPAR – SWOT Cal/Val Configuration • Flat panel low profile design compatible with multiple aircraft. • Solid-state, conduction cooled design enable operation unpressured up to 70 kft. • SolidWorks design shows KaSPAR installed in King Air instrument bay. • Current NASA aircraft: NASA King Air, Global Hawk (aft port), and Ikhana (nose). • Multi-baseline along and cross track to support SWOT studies and provide phase unwrapping. • Modular design can deploy single baseline configurations for reduced size. • Low CTE Panel provides rigid design to prevent deflections and has several mounting configurations. Dimensions in inches. 74 cm 60 cm (Courtesy of Carrie Rhoades, NASA Dryden.) KaSPAR Installation Locations 2011 Interdepartmental Hurricane Conference – Miami, FL

9. KaSPAR Performance • KaSPAR Performance / Measurements: • Single-pass, multi-baseline cross and along track InSAR. • Compact, solid-state, conduction cooled Ka-band design enabling high altitude operation. • Maps wetlands, river and ocean topology (cross track baselines), velocity (along track baselines) intensity. • Novel internal calibration measures system magnitude and phase drifts to better than 0.01 dB and 0.006 degrees, respectively. • Capable of high altitude (>70 kft) deployment. • Also applicable to terrestrial mapping. 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. 2011 Interdepartmental Hurricane Conference – Miami, FL

10. Science and Operational Applications • Weather reconnaissance (storm surge prior to landfall). • Search and rescue. • Flood mapping / damage assessment. • Sea ice/Freeboard mapping. • Estuarine environments and dynamics. • Flooding dynamics and flood plain mapping • Ice-covered lakes or rivers including of ice-breakup. • Pollutant transportation and imaging. 2011 Interdepartmental Hurricane Conference – Miami, FL

11. GLISTIN Measurements - Gulfstream III Google Maps GLISTIN Radar 3D Imagery (fast product) GLISTIN Radar 2D Imagery (fast product) RSS & JPL GLISTIN/IPY Project 2011 Interdepartmental Hurricane Conference – Miami, FL

12. RSS Ka-band Elevation Mapper on the NASA Gulf Stream Ka-band InSAR • RSS and Jet Propulsion Laboratory (JPL) Project. • Ka-band InSAR integrated into NASA UAV SAR. • Demonstrate single pass elevation mapping with a Ka-band InSAR. • Several missions executed in May 2009 over Greenland, current funding to further analyze measurements and 2010/11 funding likely to convert prototype system to operations. • Technology / experience transfer to KaSPAR. 15 km Images were generated from data collected on the second Ka-band engineering test flight on March 16, 2009. Aircraft flew on a heading of 180° and imaged from San Dimas, CA to Irvine, CA at an altitude of 6000 m. The data was processed to a height map with posting of 3 meters; with height accuracies as good as 30 cm in the near range. 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 mapping over Jakobshavn glacier. Repeat observation after 6 days reveal 1km horizontal movement. Ka-band InSAR on Gulfstream III 2011 Interdepartmental Hurricane Conference – Miami, FL

13. RSS – 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 2011 Interdepartmental Hurricane Conference – Miami, FL