Abstract:

By utilizing the global solar radiation data and precipitation observations collected in a land － atmosphere interaction field experiment
in the Badain － Jaran Desert，we explored the influencing factors of local atmospheric transmittance derived from monthly
mean diurnal variation of horizontal global solar radiation during the whole experiment． The results show that atmospheric transmittance
was enlarged by the summer precipitation with wet removal of dust aerosol， and mean atmospheric transmittance in clear days was also
increased by about 9． 0% after rainfall event，which particularly affected the global solar radiation reaching to the land surface． Moreover
comparative analysis of atmospheric transmittance before and after rainfall event show that the augment of moisture transfer from the
surface caused by evapotranspiration after rainfall event has no significant effect on atmospheric transmittance． Therefore， the summer
rainfall can lead to direct increase for atmospheric transmittance， and so solar radiation on the land surface in desert of western China
would increase．

Key words:  desert, solar radiation, transmittance

摘要：

利用在巴丹吉林沙漠开展的陆表能量水文过程野外综合试验太阳辐射及降水等观测资料，分析了试验期间到达地表的太阳辐射的时间分布特征和影响局地大气透明度的因子。结果表明: 夏季降水不仅对浮尘天后的大气透明度有明显的改善作用，而且在完全晴日间的降水也使日平均大气透明度增加约9． 0%，进而对到达地表的太阳辐射产生较大影响，而近地层的蒸散增强导致的空气湿度增加对局地大气透明度的影响可以忽略。因此，在我国西北干旱区沙尘多发地带夏季降水事件后，到达地表的太阳辐射能有明显增加的趋势。

关键词: 沙漠, 太阳辐射, 透过率, 降水