塔克拉玛干沙漠近地层湍流热通量计算方法比较研究

Comparison of Calculation Methods for Turbulent Heat Flux over Atmosphere Surface Layer in Taklimakan Desert

利用2007年8月3日至10月31日在塔克拉玛干沙漠大气环境观测试验站取得的大气边界层观测资料,比较了涡动相关法、波文比法和空气动力学法计算得到的湍流热通量,分析了塔克拉玛干沙漠腹地能量平衡各分量的日变化特征。结果表明:波文比法、空气动力学和涡动相关法计算得到的塔克拉玛干沙漠腹地湍流热通量日变化特征是一致的,整个观测期间,空气动力学方法和波文比法计算得出的湍流通量大于涡动相关法。它们的顺序分别为,波文比法计算得出的湍流热通量最大,空气动力学方法次之,涡动相关法最小;塔克拉玛干沙漠腹地能量平衡各分量基本上以12:00时为中心,呈对称分布。净辐射、土壤热通量、感热通量具有非常明显的日变化特征。净辐射日最高值324 W.m-2出现在当地时间11:30,最小值-85 W.m-2出现在当地时间18:30;土壤热通量在12:00左右达到日最高值143 W.m-2,而20:00时出现最小值-69 W.m-2;感热通量在13:30时左右达到最高值178 W.m-2,19:00时左右出现最小值-7 W.m-2;相对于上述3个能量平衡分量,潜热通量的日变化特征不太明显。每日12:30左右出现潜热通量的最大值43 W.m-2,06:00时出现日最低值-1 W.m-2。

Eddy Covariance, Bowen Ratio Energy Balance （BREB） and Aerodynamics methods are inter-com- pared in calculation of turbulent heat flux based on data from August 3 through October 31, 2007 observed at the Taklimakan Desert Atmospheric Environment observation Station. The characteristic of diurnal variation for sensible and latent heat flux obtained by the Flux Profile Method and the BREB Method are same as those by the Eddy Covariance Method. However, the sum of sensible and latent heat flux measured by the Eddy Correlation System was smaller than that by Flux Profile Method and BREB Method. The pattern of energy partition took on inverse ＂U＂shapes according to their diurnal changes. In the daytime there is a noticeable variation in the net radiation, soil heat flux and sensible heat fluxes： the daily peak of net radiation（324 W·m-2）, soil heat flux（143 W·m-2） and sensible heat flux（178 W·m-2） emerges at 11：30, 12：00, 13：30 correspondingly; the daily nadir of net radiation（--85W·m-2）, soil heat flux（--69 W·m-2） and sensible heat flux（--7 W·m-2） emerges at 18：30, 20：00, 19：00 correspondingly. In contrast to small variation in the latent heat flux, the daily peak of 43 W. m-2 occurred at 12：30 and daily nadir of --1 W·m-2 occurred at 06：00.