MM5中尺度模式对一次冷锋天气系统模拟结果的评价

运用MM5模式对2001年3月6-9日华东和华南地区一次冷锋天气系统进行了模拟,模拟的冷锋向南推移进度比观测的锋面大概滞后2～4h。模拟的海平面气压场和观测结果基本吻合。香港3个站点的模拟近地风场在积分的第35～40h时间段的值比观测结果稍偏北、偏大,但总体趋势一致。模拟的相当位温场能较好反映此次冷锋线的位置及南移趋势。500和850hPa位势高度场及风场的模拟结果反映出这段时期华西北-华北高压带的增强、南移及华西南-华中一带低压区的逐渐减弱过程。低压槽在一定程度上对冷锋的南下提供动力上的支持,冷锋的南下加速了低压槽的消散进程。

Application of Mesoscale Model MM5 to a Cold Front Weather System

Using the mesoscale model MM5, the cold front in South China and East China from March 6 to 9, 2001 was modeled. There is 2 to 4 hour lag between the simulation movement of the cold front and the observation result. The simulated result of sea level pressure agrees with the observated data. The time series near-surface simulation wind velocity is larger and wind direction is more northerly than the observation result from 35th to 40th hour in 3 stations in Hong Kong, but as a whole the two results are accordant. The simulation equivalent potential temperature shows the position of the cold front moved southward. The numerical results of the geopotential height and wind fields in 500hPa and 850hPa show that the high pressure in north and northwest China was strengthened and moved south and the low pressure in Southwest China and middle China was weakened. The trough of low pressure provided some power for the movement of the cold front to a certain extent and the front speeded up the disappearance of the trough of the low pressure.