Characterization of meteorological parameters, solar radiation and effect of clouds at two antarctic sites, and comparison with satellite estimates

The analysis of measurements of daily mean temperature, daily mean relative humidity and daily total solar irradiation for the period 1979-1985, at the Antarctic stations Almirante Brown (64.9ºS, 62.9ºW, 10m a.s.l., West of Antarctic Peninsula), and BelgranoII (77.9ºS, 34.6ºW, 250m a.s.l., East of Antarctic Peninsula) is presented. A short-term characterization of monthly averages was established. Typical temperatures for summer and winter were 2ºC and -7ºC respectively at Brown, and -2ºC and -20ºC at BelgranoII. Relative humidity was always above 60% at both stations. Both measured parameters enter also as input variables in model calculations of the equivalent clear-sky daily total irradiation for each day, to determine the effective cloud transmittance of solar radiation. The effect of cloudiness was stronger at Brown, where an average cloud transmittance of 49% was determined, while it was of 71% at BelgranoII. Average daily irradiation of 27.4MJ/m² in December at BelgranoII is within the highest reported world-wide. Also, some days show increases in the daily irradiation over 20% than that expected for clear-sky conditions. Antarctic solar irradiation levels are considerably higher than in the Arctic. Ground-based data are compared with the satellite database from NASA Surface Meteorology and Solar Energy Data Set.