Accession Number : ADP007285

Title :   Cloud Radiative Effects and Associated Changes in Tropospheric Temperature and Winds at the South Pole During Austral Winter,

Corporate Author : COLORADO UNIV AT BOULDER

Personal Author(s) : Stone, Robert S. ; Kahl, Jonathan D.

Report Date : MAR 1992

Pagination or Media Count : 6

Abstract : Both the increasing concentrations of greenhouse gases and potential changes in cloud distributions are likely to affect the surface energy budget of the polar regions. Changes in the polar atmosphere are, linked to dynamical processes that control the transport of mass, heat, and moisture from lower latitudes and in turn, feed back into the global circulation. An assimilation of radiation and meteorological data collected at the South Pole during the 1986 austral winter is analyzed to gain a better understanding of the relationships between cloud radiative effects, transport processes and the vertical distribution of temperature and wind. An algorithm is developed to characterize the quasi-permanent surface-based temperature inversion and the warm radiatively active layer above it. Mean winter temperature and wind profiles for clear and overcast conditions are, combined with surface radiation measurements to study the mechanisms that cause periodic weakening of the inversion. Results support previous studies that ascribe this weakening to (1) warm air advection, (2) downward vertical mixing of sensible and latent heat, and (3) longwave cloud radiative heating. The integrity of the inversion depends on the combined effects of all three mechanisms. Parameters representing the intensity of the inversion and the bulk wind shear through the lower troposphere are suggested as appropriate indices for the detection of climate change in the region of the Antarctic Plateau.

Descriptors :   *CLIMATE, *CLOUD PHYSICS, *CLOUD COVER, *SOLAR RADIATION, CIRCULATION, DETERMINANTS(MATHEMATICS), DISTRIBUTION, GLOBAL, GREENHOUSE EFFECT, INVERSION, LATENT HEAT, METEOROLOGICAL DATA, PARAMETERS, POLAR REGIONS, PROFILES, RADIATION, REGIONS, SURFACE ENERGY, TEMPERATURE INVERSION, TRANSPORT, TROPOSPHERE, WIND SHEAR, ENVIRONMENTAL IMPACT.

Subject Categories : Meteorology
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE