FIRESHEBA

FIRE-Arctic Cloud Experiment/SHEBA

19 May 1998 - 24 June 1998

Lead Scientist: Peter Hobbs

Observatory: NSA (North Slope of Alaska)

Based in Barrow, Alaska, from May 15 through June 24, 1998, the Univ. of Washington carried out 23 research flights, amounting to 97.26 hours, in support of FIRE-ACE/SHEBA (Surface Heat Budget of the Arctic Ocean). The main goals of the flights were to measure the radiative properties and microphysical structures of various cloud types in the Arctic, to measure the BRDF and albedos of various surfaces (ice, snow and tundra) and various cloud types, and to obtain these measurements whenever possible either beneath the NASA ER-2 aircraft, over the SHEBA ship, or over the ARM site in Barrow for the purpose of comparing remote sensing and in situ measurements. Considerable data were collected relevant to all of these goals. The data include: 10 sets of measurements over the ARM site (many with vertical profiles from close to the surface to above the main cloud and/or aerosol layers, and BRDF and albedo measurements), 8 flights over the SHEBA ship (including vertical profiles of cloud and aerosol properties, and BRDF and albedo measurements), and 4 flights beneath the ER-2 (three over ARM and one over the SHEBA ship). Other studies were carried out over the Chukchi Sea. Measurements of cloud optical and radiative properties, and cloud microstructures, were obtained in stratus, altocumulus, and cirrus clouds. Total flight paths in stratus/stratocumulus, altocumulus, and cirrus/altostratus were approximately 1750, 900, and 5300 km, respectively. Aerosol measurements were obtained in arctic haze layers, some no doubt from long-range transport, and also under very clean conditions. Several new (or modified) instruments were operated on the CV-580 including the Gerber Scientific g-meter, the Pilewskie Solar Spectral Flux Radiometer (SSFR), the NASA-Goddard/U. of Wash. Spectral Scanning Radiometer, and the SPEC Inc. Cloud Particle Imager. This was the first field deployment of the Univ. of Wash's Convair-580 research aircraft. The aircraft performed very well, exceeding expectations in several respects. For example, the aircraft reached an altitude of 31,000 ft, and was able to deploy to the SHEBA ship, with adequate time on station to obtain measurements, even when the ship was well over 400 nm from Barrow.