Airborne Multi-angle Imaging SpectroRadiometer (AirMISR) Data from the CLAMS 2001 Campaign

The AIRMISR_CLAMS_2001 data were acquired during the CLAMS campaign on July 12, July 17, August 1, and August 2 of 2001. The Jet Propulsion Laboratory (JPL) in Pasadena, California provided the data. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign was held in the summer of 2001 at the CERES Ocean Validation Experiment (COVE) site in the Chesapeake Bay, 20 km east of Virginia Beach. CLAMS is a clear-sky, shortwave closure campaign in conjunction with MISR, CERES, MODIS-Atmospheres and the Global Aerosol Climatology Project (GACP). Its goals were to obtain more accurate broadband fluxes at sea surface and within the atmosphere, space-time variability of spectral BRDF of the sea surface, and aerosol retrievals. The Airborne Multi-angle Imaging SpectroRadiometer (AirMISR) is an airborne instrument for obtaining multi-angle imagery similar to that of the satellite-borne Multi-angle Imaging SpectroRadiometer (MISR) instrument, which is designed to contribute to studies of the Earth's ecology and climate. AirMISR flies on the NASA ER-2 aircraft. The Jet Propulsion Laboratory in Pasadena, California built the instrument for NASA. Unlike the satellite-borne MISR instrument, which has nine cameras oriented at various angles, AirMISR uses a single camera in a pivoting gimbal mount. A data run by the ER-2 aircraft is divided into nine segments, each with the camera positioned to a MISR look angle. The gimbal rotates between successive segments, such that each segment acquires data over the same area on the ground as the previous segment. This process is repeated until all nine angles of the target area are collected. The swath width, which varies from 11 km in the nadir to 32 km at the most oblique angle, is governed by the camera's instantaneous field-of-view of 7 meters cross-track x 6 meters along-track in the nadir view and 21 meters x 55 meters at the most oblique angle. The along-track image length at each angle is dictated by the timing required to obtain overlap imagery at all angles, and varies from about 9 km in the nadir to 26 km at the most oblique angle. Thus, the nadir image dictates the area of overlap that is obtained from all nine angles. A complete flight run takes approximately 13 minutes. The 9 camera viewing angles are: 0 degrees or nadir 26.1 degrees, fore and aft 45.6 degrees, fore and aft 60.0 degrees, fore and aft 70.5 degrees, fore and aft. For each of the camera angles, images are obtained at 4 spectral bands. The spectral bands can be used to identify vegetation and aerosols, estimate surface reflectance and ocean color studies. The center wavelengths of the 4 spectral bands are: 443 nanometers, blue 555 nanometers, green 670 nanometers, red 865 nanometers, near-infrared two types of AirMISR data products are available - the Level 1 Radiometric product (L1B1) and the Level 1 Georectified radiance product (L1B2).