THE VARIATION CHARACTERISTICS OF RADIATION BUDGET COMPONENTS  OF THE WESTERN TIBETAN PLATEAU IN 1997/1998

Based on the Automatic Weather Station (AWS) radiation budget observation data of China-Japan Asia Monsoon Mechanism Project on the western Tibetan Plateau in September 1997 and October 1998, the seasonmean diurnal variation and an nual variation features of the radiation budget components were analyzed on the Gaize and Shiquanhe stations of the west plateau. The results were compared to t he QinghaiXizang Plateau Meteorological Experiment (QXPMEX) in 1979 and the Pl ateau heatsource experiment in 1982 and 1983. It shows that the radiation budg et components of the western plateau are found except the differences of its sea sonal and annual changes, the differences between the regions are probably very important too. For example,（１）the global solar radiation difference between the spring (average from March to May) and summer (average from June to August) were very small, the spring mean diurnal variation maximum was larger than that of the summer at Gaize station；（２）due to the influence of the earth surface condition, the differences of surface albedo were very large in different areas or different years. In December 1997, the values of albedo were as much as 0.5 and 0.57 at Gaize and Shiquanhe, respectively. Their values were 0.24 and 0.23 in August, they were the minimum in annual variation. But in 1979, the albedo was the smallest in July, the value was 0.24, it increased to 0.27 in August. The al bedo values of two stations were different, the annualmean albedo at Gaize sta tion was 0.02 more than that of Shiquanhe;（３）the diurnal and annual variatio n of the atmospheric counter radiation were different with other components, the phases of the diurnal maximum was 3-4 hours late than global solar radiation an dearth surface radiation, the monthmean maximum was 1-2 or 2-3 months late th an global solar radiation and earth surface radiation, respectively; (4)the month mean maximum and minimum of Gaize station were about 1 month late than Shiquan he, therefore, the radiation budget at Gaize were almost less than Shiquanhe fro m winter to summer, but they were reverse from summer to winter.