An Overview of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment
Abstract
The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign was successfully executed over the middle Atlantic eastern seaboard from July 10-August 2, 2001. CLAMS is a radiative closure experiment designed to validate and improve EOS TERRA satellite data products, namely, radiative flux profiles retrieved from CERES (Clouds and Earth's Radiant Energy System) and aerosol properties retrieved from MISR (Multi-angle Imaging Spectro-Radiometer) and MODIS (MODerate Resolution Imaging Spectroradiometer). Central to CLAMS experimental strategy is the Chesapeake Lighthouse located in the Atlantic Ocean, 13 miles east of Virginia Beach near the mouth of the Chesapeake Bay and the site of an ongoing CERES Ocean Validation Experiment (COVE). Unlike a ship or bouy, the Chesapeake Lighthouse is a stable sea platform, well offshore, on which radiometers are elevated 25-40 m above the sea surface (and hence above the most intense sea spray). Nevertheless, the measurement of upwelling radiation may be problematic owing to the possible effect of the platforms legs both directly (the legs reflect light) or indirectly (the legs generate foam and bubbles). This paper focuses on analyses of the shortwave radiation measurements made from the NASA Langley OV-10 aircraft during CLAMS. The OV-10 aircraft is instrumented with commercial uplooking and downlooking broadband 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. 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 in clear-sky and overcast conditions to help understand the platform effects. The variation of ocean optical properties in the vicinity of COVE is examined. The measured spectral albedos are compared to those inferred from the CAR data in discrete wavelength bands. The broadband SW fluxes are compared for consistency to similar measurements made from the Convair 580 which had greater horizontal range than the OV-10 and was able to achieve broadband albedo measurements over the darker ocean farther offshore.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2002
- Bibcode:
- 2002AGUSM.A21D..02S
- Keywords:
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- 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0305 Aerosols and particles (0345;
- 4801);
- 0320 Cloud physics and chemistry;
- 0394 Instruments and techniques;
- 0399 General or miscellaneous