三峡库区对局地暴雨和江面大风影响的理论模型

从考虑水汽凝结潜热作用的两维非静力平衡方程组出发,利用江陆边界条件,从理论上求得适用于陆地水体的解析解。结果表明,当0〈k〈1.0℃·km-1时（k为水汽凝结潜热）,江风环流比陆风环流强,两岸比江面容易形成暴雨;当k〉1.0℃·km-1时,江风环流比陆风环流弱,江面比两岸容易形成暴雨;当0.5℃·km-1≤k≤0.9℃·km-1时,江陆面上方低层易出现大风。在江陆风环流中心附近流线出现与锋面类似的间断面,可用于解释雷达图上的海陆面上空类切变线的线状回波。此回波与冷锋相遇,易形成暴雨。

A theoretical model of the effect of the Three Gorges Reservoir on local torrential rain and strong breezes over the reservoir

By using the two-dimensional non-hydrostatic equations and the effect of latent heat of condensation,together with the river-land boundary conditions,we obtain a set of theoretical solutions which is applicable for river-land breeze.The results show that：when 0k1.0 ℃·km-1,the circulation of river breezes is stronger than that of land breezes,which leads to the occurrence of heavy rain over the land more easily than over the reservoir;when k1.0 ℃·km-1,the circulation of river breezes is weaker than that of land breezes,which makes heavy rain occur more easily over the reservoir than over the land.There are strong surface winds when 0.5 ℃·km-1≤k≤0.9 ℃·km-1.The interfaces of the streamlines around the centre of the circulation may be an explanation for the linear echoes which are analogous to shear lines above the land-sea surface on the radar chart.The heavy rain occurs easily when the echoes meet cold front.