地形及冷热源扰动不同分布对南沙海域西南大风形成过程影响的数值试验

THE NUMERICAL EXPERIMENTS OF SOUTHWESTERLY FORMATION OVER THE NANSHA SEA AREA WITH THE EFFECTS OF TERRAIN AND HEAT PERTURBATION

利用一个ｐ－σ混合坐标五层原始方程模式，进行了地形及冷热源扰动的不同分布对南沙海域西南大风过程形成作用的数值试验。结果表明，亚洲南部特殊的地形及海陆分布是形成南沙海域西南大风过程的基本条件，但它造成的最大风速只能达８ｍ／ｓ，比观测值要小．试验中发现，在有地形作用的前提下，澳大利亚冷空气的向北爆发及菲律宾附近热源扰动的作用均可各自在南沙海域形成１２ｍ／ｓ以上的大风过程，而孟加拉湾附近的热源扰动则对南沙海域西南大风过程的形成无明显作用。

By using a five layer limited area primitive equations model,the terrain’heatingperturbation over South Asia and a cooling perturbation over Australia are incorporated,respectively in the numerical model to discuss their effects on the southwesterlyformation over the Nansha Sea area。 The experiments of terrain show that thetopographic effect is necessary on the southwesterly formation, but the topographiceffect is not strong enough to rnake the southwest wind velocity reach 12m/s.Furthermore, with the help of the effect of terrain , the experiment results includingheating perturbation over the Philippines and the cooling perturbation over Australia,respectively,show that they can both make the southwesterly formation of above 12m/sover the Nansha Sea area. However,the heating perturbation over the Bay of Bengal hasno effect on the fornation of southwesterly over the Nansha Sea area.