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NASA’s Coastal and Ocean Airborne Science Testbed (COAST). L. Guild 1 *, J. Dungan 1 , M. Edwards 1 , P. Russell 1 , S. Hooker 2 , J. Myers 3 , J. Morrow 4 , S. Dunagan 1 , P. Zell 1 , R. Berthold 1 , and C. Smith 1 1 NASA Ames Research Center, Moffett Field, CA, USA
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NASA’s Coastal and Ocean Airborne Science Testbed (COAST) L. Guild1*, J. Dungan1, M. Edwards1, P. Russell1, S. Hooker2, J. Myers3, J. Morrow4, S. Dunagan1, P. Zell1, R. Berthold1, and C. Smith1 1NASA Ames Research Center, Moffett Field, CA, USA 2NASA Goddard Space Flight Center, MD, USA 3Univ. of Calif., Santa Cruz/NASA Ames, Moffett Field, CA 4Biospherical Instruments Inc., San Diego, CA, USA
COAST Objectives Needs: Research capability to address the challenges of remote sensing in the optically complex coastal environment, currently unachievable using satellite resources • Develop and integrate the first end-to-end instrument suite for simultaneous measurements of ocean color (modified imaging spectrometer), aerosol optical depth and water vapor column content (sunphotometer), and water bio-optical measurements (microradiometer-based multiwavelength radiometer package) using inputs from an associated precision navigation system. • Advance calibration and validation (cal/val) of satellite ocean color through airborne campaigns of the COAST instrument suite flown in conjunction with satellites and in conjunction with in situ ship-based cal/val measurements and moorings. • Produce high spatial resolution (5-10 m), atmospherically corrected and geolocated ocean-color products (calibrated to at-sensor radiance) that will advance understanding of coastal freshwater and marine processes and productivity and improve coastal models.
COAST Mission Overview • Remote Sensing in the Optically Complex Coastal Zone • Airborne remote sensing is used to infer properties of the coastal zone. • High spatial resolution is needed to capture high spatial heterogeneity. • Airborne reflectance spectra are composites of reflectance from: • 1) the atmosphere (particles, gases); • 2) the sea surface; • 3) the water column (water molecules, phytoplankton, colored dissolved organic matter); and • 4) the bottom (sediments, seagrass, corals). 1 2 3 4 Nov 17, 2010
Headwall Ocean Color Imaging Spectrometer Spectrometer: Concentric Pushbroom (Offner-type) Spectral Range: 380 – 760nm* Dl = 10 nm (@ off-chip binning of 1.5nm pixels) Bands: 40* Spatial Elements: 700 IFOV: 1.23 mrad FOV: 46.7 degrees Weight: 20+ lbs; Power: 30 Watts Array: 1600 x 1200 pixels (7.4mm) @ -30C Grating optimized at 450 nm Spectral Smile: <0.25 Pixel (0.625nm) Keystone: <0.9 pixel (6.6mm) Dispersion: 100 nm/mm, linear to <0.5%** * No order-sorting ** Modeled values
14-channel Ames Airborne Tracking Sunphotometer (AATS-14) Measures: Solar direct-beam transmission, T, at 14 wavelengths, l=354-2139 nm Data products • Aerosol optical depth (AOD) at 13 l, 354-2139 nm* • Water vapor column content • Ozone column content** • Aerosol extinction, 354-2139 nm • Water vapor density *+ 3-parameter fit (useful for interpolating) **Requires low sun, AOD(600 nm)<~0.03
Monterey Bay Flight Planning Headwall AATS-14 Microradiometers Alt = 12,000 ft 8 m GSR (Max alt w/o O2) Alt = 6000 ft 5 m GSR Alt = 4500 ft 4 m GSR Headwall AATS-14 Microradiometers AATS-14 Alt = 100 ft (Lowest safe aircraft alt.) (Any speed okay) AATS-14 Microradiometers
Monterey Bay Flight Planning Flight line orientation optimized to avoid sunglint
Scientific Outcomes • A flight-tested instrument suite suitable for cal/val activities for future satellite missions, as well as currently operating and developing missions. • Advanced payload capabilities for airborne carrier platforms including UASs. • A multi-sensor ocean/atmosphere data set available for improved atmospheric calibration and in-water algorithms. • Methodologies for empirical atmospheric correction developed for future airborne imagers of this type (e.g., NASA PRISM) when they come online. • Methods to address the biological properties of important coastal zone ecosystems. • Enabling technology for a broad range of research activities in the coastal zone to support the scientific community’s research goals and objectives. Contact: liane.s.guild@nasa.gov