间断地形下的亚惯性频率地形波

DISPERSION RELATIONS OF SUBINERTIAL TOPOGRAPHIC WAVES WITH DISCONTINUOUS DEPTH PROFILE

在纯间断化地形的条件下,从理论分析和数值计算二方面探讨了亚惯性频率地形波的频散关系。指出正压亚惯性频率地形波的波模直接取决于间断点的个数和间断度。连续地形可以看成是纯间断地形的极限情况,因此,连续地形的起伏程度有类似间断度的作用。在对连续地形的频散关系进行数值计算时,水平步长的选取对计算结果有很大的影响。

A traditional numerical model for calculating the dispersion relations of general barotropic subinertial topographic waves is improved. The new numerical model is suitable not only for continuous topography but also for a noncontinuous one. Besides, a detailed theoretical analysis to the case of an arbitrary purely discontinuous topography is presented. The results of the analysis suggest that the number and types of modes of barotropic subinertial topographic waves in that case are determined completely by the number of discontinuous points and their discontinuity-rates. Because a continuous topography is the limited case of a purely discontinuous one, the slope of a continuous topography will have the same role to the wave modes as the discontinuity-rate of purely discontinuous topography. As a result, the difference of horizontal resolution to a depth profile in the calculation may affect the results greatly, especially in the part of short wave.