'98南海季风(SCSMEX)和高原科学试验(TIPEX)边界层

摘要

A dynamic study on Ekman characteristics by using 1998 SCSMEX and TIPEX boundary layerdata is made. The results are as follows: (1) Similar dynamical Ekman characteristics are observed in theTibetan Plateau and in the South China Sea and its surrounding area. (2) The thickness of the boundarylayer is about 2250 m over the Tibetan Plateau, and considering its variation, the thickness could be up to2250-2750 m. In the tropical southwest Pacific, the thickness of the boundary layer is about 2000 m, andthe variation is smaller; a smaller thickness of the boundary layer is in the plain area of the Bohai Sea.(3) Because of the difference in elevation between the Tibetan Plateau and the tropical ocean area, theinfluence of the boundary layer on the atmosphere is quite different although the two areas have almostthe same thickness for the boundary layer, the height where the friction forcing occurs is quite different.(4) The vertical structure of turbulence friction is quite different in the Plateau and in the tropical oceanarea. Calculations by 1998 SCSMEX and TIPEX boundary layer data indicate that even in the lowestlevels, eddy viscosity in the Tibetan Plateauan can be 2.3 times than in the tropical ocean area.%使用1998年南海季风(SCSMEX)试验和青藏高原科学试验(TIPEX)的边界层资料对Ekman特征进行了动力学研究.得到如下结果:(1)在青藏高原和南海及其周围区域有类似的Ekman动力学特征.(2)比较研究表明,边界层厚度在青藏高原约为2250 m且考虑到它的摆动特性,其厚度可在2250-2750 m之间.在热带西南太平洋边界层厚度约为2000 m,其厚度摆动较小,在平原地区边界层厚度较低.(3)由于高原和热带海域海拔高度的不同,尽管在高原和热带海区有着几乎同样的边界层厚度,但边界层对大气的影响是相当不同的.考虑到海拔高度的影响,在这两个地区摩擦力作用的空间部位的高度有相当大的差别.(4)这两个区域的湍流摩擦的垂直结构差异较大.使用'98 SCSMEX和TIPEX边界层资料计算结果表明,即使在低层,平均湍流粘性力在高原上是热带海域的2.3倍.