Abstract:

A measurement project to obtain continuously surface radiation balance components as a part of CHINARE-IV research program was carried out over the Laresman Hills on which Zhongshan station (69?22'S, 76?22' E) is located, from Feb. 1990-Jan. 1991. The micro-computer sampling system was used with pyranometers and pyrradiometers for measurement of radiation flux, including direct solar radiation, global radiation, reflected radiation and net radiation (0.3-30μm). These values were sampled digi tally and recoided every minute at the height of 1.5m above the surface. In this paper, on basis of the data series obtained between Feb. 1990 and Jan. 1991 , analyses of seasonal means of these component in response to changing synoptic conditions are presented. Each radiative element has a characteristic of the marked diurnal and seasonal variation. In the summer, the flux of direct radiation is stronge, while in winter it is small (it becomes zero during polar night of 58 days). The transparent coefficients (Pm=/Sm/S.) are generally over 0.8 with a small seasonal change, indicating that the transparency of the atmosphere in sunny day is very high and the air is very clea n with few aerosol particles in it. The annual mean value of the global radiation is 119.2 W/m2 about 90% of which is obtained between October-March, The peak value of the instantaneous flux could be as large as 1095W/m2 since the cloud has a strong effect ons catting radiation in December. The annual mean albedo is 0.42, and the albedo varies very large from day to day because of changing status of the snow surface closely related to the weather condition. The mean albedo in the summer is 0.27 on the bareland surface and it is 0.51 in the cold season on the snow surface. The albedo over 0.9 could be observed on the fresh snow covered surface. The annual mean value of the net radiation is 11.7 W/m2.It is indicating that the surface of the region is a heat source to the air. Therefore the budget of the radiation energy over the region differs greatly from that in Antarctic inland area. The mean value of the net radiation from October to March is positive (64.1 W/m2) and it is negative (-40.6 W/m2) in rest time. It means that the heat is absorbed by the surface in summer half year, and the heat lost from surface in the winter half year. This variation should be considered in analysis on the effect of the polar radiation status on the global circulation.