Aircraft Measurements of Spectral and Broadband Shortwave Albedo from the NASA Langley OV-10
Smith, W.L., Jr.(a), Charlock, T.P.(a), Roback, V.E.(a), Rutledge, C.K.(b), and Zhang, T.P.(b), NASA Langley Research Center (a), Analytical Services and Materials, Inc. (b)
Twelfth Atmospheric Radiation Measurement (ARM) Science Team Meeting
In order to validate and improve surface radiative fluxes derived as part of the Clouds and the Earth's Radiant Energy System (CERES) program, The CERES Fixed-wing Airborne Radiometer (CFAR) was developed to make measurements of upwelling and downwelling shortwave (spectral and broadband) and longwave (broadband) radiative fluxes. The CFAR consists of an OV-10A Bronco twin-turboprop, originally developed for military applications but chosen by NASA for atmospheric radiation measurements based on its performance envelope, ruggedness, relatively large cargo area, aft cockpit capacity for housing research equipment, and relatively low cost to operate and maintain. The aircraft is instrumented with commercial broadband (currently Eppley's) and spectral radiometers. The spectral radiometers are the Analytical Spectral Devices, Inc. Full-Range Fieldspec which measure hemispheric solar irradiance from 350-2200 nm with a resolution of 7-10 nm. This paper focuses on measurements taken over the ocean in support of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) campaign conducted in July 2001 in the vicinity of the ongoing CERES Ocean Validation Experiment (COVE), a unique oceanic EOS validation site 25 km east of Virginia Beach. During CLAMS, the OV-10 was primarily flown at low-altitude (100-600 ft) to characterize ocean optical properties in the vicinity of COVE and to compliment spectral BRDF measurements made from the Cloud Absorption Radiometer (CAR) aboard the University of Washington Convair-580. Broadband and spectral albedos derived from the aircraft data are compared to measurements from COVE to help understand the platform effects. The variabilitiy in ocean optical properties in the vicinity of COVE is examined. a few measurements taken over land targets are also presented. Spectral albedo may be highly variable in space and time over land surfaces and is an important input parameter for many remote sensing applications particularly studies of aerosols and clouds that rely on radiative transfer calculations. Pending the continued fiscal support for this platform, future plans include measurements over many land-surface types and other surface radiation sites, including the ARM SGP site.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).
