The 5th Conference on Polar Meteorology and Oceanography

J10.3
THE ROLE OF SURFACE-LAYER TURBULENT INTERACTIONS IN THE LONGWAVE FLUX/SURFACE TEMPERATURE FEEDBACK DURING SHEBA

C W. Fairall, NOAA/ETL, Boulder, CO; and P. O. G. Persson, E. A. Andreas, and P. Guest


The objective of the Surface Heat Budget of the Arctic (SHEBA) program is a study of ice- albedo and ice-cloud feedbacks in the Arctic. The approach is to obtain a complete annual cycle of the terms of the surface energy budget over the pack ice in the Beaufort Sea (about 76°N). During the winter, clouds dominate the short-term variability of the downward longwave flux. However, a significant fraction of the net longwave flux is not realized as cooling/heating of the surface but is lost to the atmosphere through near-surface turbulent transfer processes. One commonly used index of this phenomenon is the ratio ( alpha) of the heat flux into the surface to the net radiative flux. Because of the anisotropic nature of this transfer, positive net radiative flux excursions are more heavily damped by the atmosphere than are negative excursions (i.e., alpha is a function of atmospheric surface layer stability). In this paper we will analyze data taken from the 5-level flux system on the SHEBA Surface Flux Group's (SSFG) 20-m tower to develop simple feedback relationships between mean variables (such as wind speed) and flux variables. We anticipate that such relationships will be useful in testing weather and climate model surface interaction parameterizations

The 5th Conference on Polar Meteorology and Oceanography