沙漠绿洲不同下垫面夏季能量收支对比分析

Comparative analysis of the surface energy budget of the different ground surface of desert and oasis in summer

利用"绿洲系统能量与水分循环过程观测试验"2005年在甘肃金塔不同下垫面的观测资料,对绿洲、戈壁和沙漠不同下垫面夏季辐射和地表能量收支及闭合特征进行了全面的时空对比分析,结果表明:(1)不同下垫面太阳向下短波辐射没有明显差距,地面短波向上辐射差别较大,大气长波向下辐射变化较小,地表长波辐射差异显著。另外,地表吸收辐射戈壁沙漠日变化较绿洲显著。(2)沙漠与戈壁各通量特征相似,而与绿洲上的有很大差异。(3)能量通量测量存在明显的不确定性:影响能量通量不闭合的原因,主要是超声和土壤热通量的测量误差。

The oases in the Northwest of China are commonly located in the desert and gobi with the unique landscape, whose energy and water circulation are of different characteristics. The processes of energy and water circulation in the oases system have always been paid much attention of geo-science workers. The characteristics of radiation in summer and the surface energy closure and exchange over oasis, gobi and desert are evaluated by using data collected during the Oasis System Energy and Water Cycle Field Experiment, which was conducted from 20 June to 8 July,2005 in Jinta County, Gansu Province of China. The conclusions are as follows： （1） There is no obvious difference in solar downward shortwave radiation from the sky to the land surface between different observations whereas lots of changes in upward shortwave from the land surface to the sky, no evident difference in downward long-wave radiation from the sky to the land surface and prodigious difference of long-wave radiation from the land surface to the sky. Otherwise the characteristics of absorption of land surface in desert change a lot comparing with ones of the Oasis. （2） Comparison of each flux between the desert and gobi did not reveal any obvious difference, but the result shows there is a huge difference in the flux between the desert and Oasis. （3） Uncertainty of the field observation of energy flux emerged during the study period, the reason to influence the energy flux not to close mainly is due to the supersonic and soil heat flux measuring error.