First Flight of NASA’s Coastal and Ocean Airborne Science Testbed (COAST) L. Guild 1, J. Dungan 1, M. Edwards 1, P. Russell 1, J. Morrow 2, S. Hooker 3, J. Myers 4, R. Kudela 5, S. Dunagan 1, M. Soulage 6, J. Livingston 7, R. Johnson 1, T. Ellis 4, N. Clinton 4, R. Dominguez 4, B. Lobitz 8, K. Martin 1, E. Fraim 4, P. Zell 1, R.Berthold 1, C. Smith 1, K. Vassigh 1, A. Demo 1, W. Gore 1, and J. Torres 9 Abstract The NASA Coastal and Ocean Airborne Science Testbed (COAST) project advances coastal ecosystems research and ocean color calibration and validation capability by providing a unique airborne payload optimized for remote sensing in the optically complex coastal zone. The COAST instrument suite combines a customized imaging spectrometer, sunphotometer system, and a new bio-optical radiometer package to obtain ocean/coastal/atmosphere data simultaneously in flight for the first time. The imaging spectrometer (Headwall) is optimized in the blue region of the spectrum to emphasize remote sensing of marine and freshwater ecosystems. Simultaneous measurements supporting empirical atmospheric correction of image data is accomplished using the Ames Airborne Tracking Sunphotometer (AATS-14). Coastal Airborne In situ Radiometers (C-AIR, Biospherical Instruments, Inc.), developed for COAST for airborne campaigns from field-deployed microradiometer instrumentation, will provide measurements of apparent optical properties at the land/ocean boundary including optically shallow aquatic ecosystems. Results of the October 2011 Monterey Bay COAST mission include preliminary data on coastal ocean color products, coincident spatial and temporal data on aerosol optical depth and water vapor column content, as well as derived exact water-leaving radiances. Science Traceability Matrix COAST Mission Payload Measures: Solar direct-beam transmission (T) at 14 wavelengths, nm Data products:  Aerosol optical depth (AOD) at 13, nm  Water vapor column content [using T(940 nm)]  Aerosol extinction, nm  Water vapor density Ames Airborne Tracking Sunphotometer (AATS) Coastal Airborne In-situ Radiometers (C-AIR) 1 NASA Ames Research Center, Moffett Field, CA 94035; 2 Biospherical Instruments Inc., San Diego, CA 92110; 3 NASA Goddard Space Flight Center, MD 20771; 4 Univ. of California, Santa Cruz/NASA, Moffett Field, CA 94035; 5 Univ. of California, Santa Cruz, Santa Cruz, CA, 95064; 6 Universities Space Research Association/NASA Ames Research Center, Moffett Field, CA, 94035; 7 SRI International/NASA Ames Research Center, Moffett Field, CA 94035; 8 Univ. Corporation at Monterey Bay/NASA Ames Research Center, Moffett Field, CA 94035; 9 NASA Postdoctoral Program/NASA Ames Research Center, Moffett Field, CA Science Mission October 2011 Flight path for October 28, Monterey Bay has both open ocean and optically complex water masses, so the full dynamic range of the sensor suites and protocols being used in the field can be evaluated. The mission consisted of flying the imaging spectrometer, together with the AATS and C-AIR on the CIRPAS Twin Otter, over an instrumented surface to evaluate the sensor suite. The AATS provides a simultaneous empirical characterization of the atmospheric column (AOD and water vapor) that will be used for atmospheric correction. During flights, we obtained MODIS Aqua and Terra, HICO, and MERIS data corresponding to contemporaneous deployment of the ship-based measurements from the R/V John Martin (Moss Landing Marine Lab). Satellite observations will be used to compare accuracy of radiance retrievals and derived products versus the Headwall imaging spectrometer, C-AIR, and the in situ measurements. C-AIR AATS Raw data at 555 nm for solar irradiance (E s ), sky radiance (L i ) reaching the sea surface, and total radiance (L t ) above the sea surface. UTC is +7hrs from local time. Left: Aerosol optical depths (AOD) calculated from AATS-14 measurements for horizontal transects on 28 Oct. at altitudes km ASL (top left) and km ASL (bottom left). The AATS-14 channel center wavelengths (in μm) are given in the legend. Right: Corresponding mean AOD spectra (symbols) and log(AOD) vs. log(wavelength) quadratic fits (dashed lines) calculated for the total column above the aircraft for the low (blue) and high (red) flight legs, and for the layer (green) bounded by the two altitudes. Vertical profiles of columnar water vapor (left), spectral AOD (middle), and spectral aerosol extinction (right) calculated from AATS-14 measurements acquired during a spiral descent over Monterey Bay on 28 October. Imaging Spectrometer Above: True color composite of Headwall imaging spectrometer raw data showing 450 nm (red), 550 (green), and 680 (blue). Pixel resolution is 4 m. Right: Enhanced raw data shows algal bloom in red. 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. Funding: NASA HOPE, Science Mission Directorate, Office of Chief Engineer, and SMD/Earth Science Division Acknowledgements Naval Postgraduate School Center for Interdisciplinary Remotely Piloted Aircraft Systems (CIRPAS) Twin Otter Team. UC Santa Cruz and Moss Landing RV John Martin field team. UC Davis Spectral Measurements Team: Mui Lay, George Scheer, and Susan Ustin. N Ship-based Measurements Underway T, S, Fluorescence At each station (2-3 stations per day): –Size fractionated chlorophyll, flow cytometry counts –CDOM, absorption spectra, nutrients –Sunphotometer spectra –Satlantic HyperPro cast, C-OPS cast –Water-leaving radiance, profile data –Backscatter/ac-S casts –ASD surface reflectance HyperPro II profile at M0 site Preliminary Data HyperPro II (Ship-based) Right: Reflectance examples for points within the red tide (red lines) and outside of the red tide (blue lines). HyperPro II remote sensing reflectance in red tide site. C-AIR measurements of the downward irradiance (Es), sky radiance away from the sun (Li) and total surface radiance (Lt) for each 30 second segment of all flight lines showed small vari- ances, but were mostly spectrally similar. Shown are spectra from 30 second segments processed for glint avoidance by PROSIT along flight line 7, , 6000 ft.