古尔班通古特沙漠的辐射热量交换分析

ANALYSIS ON RADIANT THERMAL EXCHANGE IN THE SURFACE LAYER OF GURBANTUNGGUT DESERT, XINJIANG, CHINA

位于新疆准噶尔盆地的古尔班通古特沙漠是我国第二大沙漠。根据古尔班通古特沙漠的自然条件，对不同下垫面区域的太阳短波辐射和大气长波辐射热量进行了测量。结果表明：在晴天状况下，流动沙丘和固定沙丘的热量交换差异主要是由地表状况、沙层性质和气温等因素决定的。流动沙丘区反射率与长波辐射大于固定沙丘区，并且日、季变化明显。长波最大辐射值出现在午后，近似于太阳总辐射，最小值出现在日出前；沙层热通量随着深度的增加而增大，而辐射热量传输则随其深度的增加而减小，无论是流动沙层还是固定沙层，其热通量的零界面深度却基本一致（９月份），均在３０～３５ｃｍ之间。根据上述结果，本文还讨论了沙漠区在热量交换过程中。

Gurbantunggut Desert, located in Junggar Basin, Xinjiang, is the second large desert in China, and occupies an area of about 58 000 km 2. This paper focuses on the measurement, comparison and analysis of solar short wave radiation and long wave radiation of different ground surfaces in this area. The results show that in sunny day, the differences of reflecting rate and long wave radiation of ground surface as well as thermal exchange of sand layer are mainly controlled by the conditions of ground surface, feature of sand layer, air temperature,etc.. Reflecting rate and long wave radiation of ground surface in the motive desert are bigger than that in the fixed desert, and their daily and seasonal variations are obvious. The maximum value of long wave radiation which similar to solar global radiation appears after noon, and the minimum one appears before sunrise. Heat flux of sand layer increase with depth deepenning, but heat conduction decreases with depth deepenning. The zero boundary depths in heat flux in motive and fixed sand layers are the same, which vary within a depth of 30￣35 cm (in September). The local climatic effect caused by the difference of radiative heat and feedback of the desert to the regional climate during thermal exchange in the desert are also discussed in the paper.