拉斯曼丘陵辐射平衡分量的观测研究

本文对东南极拉斯曼丘陵地区1990年2年—1991年1月近地面辐射平衡的观测资料进行了初步研究。结果表明,该地区辐射平衡各分量有明显的日变化和年变化。夏季辐射强度大,寒季小。大气透明度全年都很好,透明度系数大多在0.8以上,寒季的透明度系数略大于暖季。年平均总辐射强度为119.2W/m~2,10—3月的总辐射累积量约占全年辐射总量的90％。年平均反射率0.42,夏季裸地平均反射率为0.27,寒季雪面平均反射率为0.51。年平均净辐射强度为11.7W/m~2,地表相对大气而言是热源。10—3月净辐射强度为64.1W/m~2,4—9年净辐射强度为-40.6W/m~2,前者说明地表在该段时间内吸收热量,后者为损失热量。

OBSERVATIONAL STUDY OF RADIATION BALANCE COMPONENTS OVER LARESMAN HILLS

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.