The 5th Conference on Polar Meteorology and Oceanography

8.4
CLOUD RADIATIVE FORCING OVER THE ARCTIC DURING FIRE ACE

D A. Spangenberg, Hampton, VA; and D. R. Doelling, W. L. Smith, Jr, C. Venkatesan, L. Nguyen, R. Palikonda, P. Minnis, and F. P. J. Valero

Shortwave (SW) and longwave (LW) radiation fluxes constitute an important part of the Arctic energy budget. Extensive measurements of cloud properties and surface heat fluxes were taken during the First ISCCP Regional Experiment (FIRE) Arctic Cloud Experiment (ACE). To fully understand the role of clouds in the heat budget, it is necessary to know the constraints on the radiation fields at the top of the atmosphere. Broadband measurements from satellites were unavailable during the FIRE ACE period. To estimate the radiation budget over the Arctic and complement the surface and aircraft data, it is necessary to use SW albedos and LW fluxes inferred from narrowband measurements. This paper presents the results of an analysis of Advanced Very High Resolution Radiometer data taken by the Sun-synchronous satellites, NOAA-12 and NOAA-14, during ACE over a portion of the Arctic including the SHEBA ice camp and the ARM surface site at Barrow, Alaska. The SW albedos are derived from the AVHRR visible channel, while the LW fluxes are determined using the AVHRR infrared window, channel-4 brightness temperatures. The transformation from the narrowband data to broadband quantities is accomplished using regression formulae based on collocated NOAA-9 and Earth Radiation Budget Experiment observations taken during 1986 over the Arctic. The fluxes are determined separately for clear and cloudy scenes to determine the cloud radiative forcing over the entire domain and ACE period. Verification of the results is accomplished using broadband fluxes measured from high-altitude FIRE aircraft

The 5th Conference on Polar Meteorology and Oceanography