Airborne Surface Water Ocean Topography Mapping System Jim

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

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

Current Altimetry Limitations Satellite altimetry data have significantly advanced our knowledge of the dynamics of the ocean variability, but due to resolution and coverage constraints … Estimating the Circulation and Climate of the Ocean (ECCO-2 MIT JPL ocean current model ) • 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. 3 2011 Interdepartmental Hurricane Conference – Miami, FL

Hydrology 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 4 2011 Interdepartmental Hurricane Conference – Miami, FL

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 250 m by 250 m and to estimate discharge in rivers wider than 100 m (50 m goal) at sub-monthly, seasonal, and annual time scales. 5 2011 Interdepartmental Hurricane Conference – Miami, FL

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 (50 m resolution). • Onboard data compression over the open ocean (1 km resolution) at centimeter topography resoltuion. 6 2011 Interdepartmental Hurricane Conference – Miami, FL

Cross Track Radar Interferometry • Unlike a conventional radar (SAR) which provides a flat image, interferometric radar (In. SAR) systems provide pixel elevation through triangulation (i. e. 3 D image of scene). Cross track Distance 7 • 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 = 2 p. Dr / l = 2 p. B 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. 2011 Interdepartmental Hurricane Conference – Miami, FL

Ka. SPAR installation on NASA Dryden King Air (Solid. Works 3 D Model) 60 cm Dimensions in inches. cm 74 (Courtesy of Carrie Rhoades, NASA Dryden. ) Ka. SPAR Installation Locations 8 Ka. SPAR – 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. • Solid. Works design shows Ka. SPAR 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. 2011 Interdepartmental Hurricane Conference – Miami, FL

Ka. SPAR Performance / Measurements: • Single-pass, multi-baseline cross and along • • • track In. SAR. Compact, solid-state, conduction cooled Kaband 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 d. B and 0. 006 degrees, respectively. Capable of high altitude (>70 kft) deployment. Also applicable to terrestrial mapping. 9 Parameter Value Unit 35. 75 GHz 40 W Platform Height 35/70 kft Swath 1 5/10 km Bandwidth 80 to 450 2 MHz Mean height error 3 1. 2 to 2. 1 cm Radial velocity error 10 cm/s 0 to 27 deg Center Frequency Peak Transmit Power Incidence angles 4 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

Science and Operational Applications • Weather reconnaissance (storm surge prior to • • 10 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 icebreakup. Pollutant transportation and imaging. 2011 Interdepartmental Hurricane Conference – Miami, FL

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

RSS Ka-band Elevation Mapper on the NASA Gulf Stream Ka-band In. SAR • RSS and Jet Propulsion Laboratory (JPL) Project. • Ka-band In. SAR integrated into NASA UAV SAR. • Demonstrate single pass elevation mapping with a Ka • Ka-band In. SAR on Gulfstream III 15 km • -band In. SAR. 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 Ka. SPAR. 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. 12 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 1 km horizontal movement. 2011 Interdepartmental Hurricane Conference – Miami, FL

RSS – JPL GLISTIN Initial Results • GLISTIN Image of Greenland Coastline: • Intensity 2 D image. • 3 D 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 13 2011 Interdepartmental Hurricane Conference – Miami, FL