荒漠戈壁大气总体曳力系数和输送系数观测研究

利用“我国西北干旱区陆一气相互作用观测试验”在甘肃敦煌进行的陆面过程野外试验的观测资料,依据三种不同方法确定了干旱戈壁区动量输送的曳力系数Cd、感热和潜热交换的总体输送系数Ch和Cq。结果表明：尽管这三种方法计算的曳力系数和总体输送系数有一定的差别,但在量级上相当,尤其是Cd和Ch的平均值比较接近。本文还通过对风向的分析,剔除了附近建筑物干扰和来自绿洲湿平流的影响,得到了荒漠戈壁总体输送系数的特征及其与理查孙数的关系。

Experimental Study on Bulk Drag and Transfer Coefficients over Gobi

Utilizing the data of the intensive observation period of Dunhuang land-surface process field experiment that belongs to Land-atmosphere Interactive Field Experiment over Arid Region of Northwest China, the bulk drag coefficient C_(d), bulk sensible heat transfer coefficient C_(h)and bulk latent heat transfer coefficient C_(q)between surface and atmosphere in Gobi over arid region are obtained by three different methods. The resultshows that, these bulk transfer coefficients are different from each other, but they are the same order of magnitude, especially the mean values of C_(d)and C_(h)are very closer. However the bulk latent transfer coefficient is three time magnitudes smaller than dynamics and bulk sensible heat transfer coefficient. Moreover, through analyzing wind direction, the interference of the buildings near observational site and influence of oasis to the east of the site are eliminated. From this, the relation between the bulk transfer coefficients (or bulk drag coefficient) and the bulk Richardson number and the range of the typical values of the bulk transfer coefficients over desert and Gobi in typical arid region are obtained.