台灣地形降水的數值模擬

The Effect of Topograph of Taiwan on Precipitation by Numerical Simulation

蔡清彥(Ching-Yen Tsay) ； 滕春慈(Chung-Tsyr Terny) ； 宋樹才(Su-Tzai Soong)

《大氣科學》 12卷1期 (1985/03) Pp. 33-40

摘要

台灣的地形高聳且南北橫亙在台灣的中央。當大範圍環繞氣流是潮濕且不穩定時，受到地形的影響往往造成暴雨成災。自數值模擬的結果發現當綜觀場是潮濕不穩定的西風至南風時，氣流受到地形的阻擋在中南部可以形成三個降水中心（台中山區、嘉義山區及南部山區）。降水中心及範圍和垂直速度中心及範圍相當一致。此垂直速度的形成不完全是氣流受到地形的抬升所造成。氣流遇到地形後有繞著台灣南北成氣旋式與反氣旋式環流的趨勢，形成了速度的輻散與輻合也影響了垂直速度的大小與分佈。就是由於此困素所以在西風至南風的範圍內，風向的改變對降水分佈的影響不大。又積雲發展後，潛熱的釋放也增加了垂直速度及其範圍。

並列摘要

The central mountain range of Taiwan is very steep and is the major factor causing terrential rainfall in Taiwan. In this study, the effect of topography on precipitation is simulated by a meso-scale numerical model developed by Mathur in 1982. It is found that, under the influence of southwest monsoon in summer, there are three major precipitation centers in central and southwestern Taiwan. The precipitation centers coincide with the centers of upward motion. The vertical motion is caused not only by prevailing upslope wind but also by mountain induced low-level convergence. The precipitation pattern is similar for the prevailing wind direction varying from the west, the southwest, to the south. It is also found that the upward motion will be enhanced by latent heat release of cummulus convection.