湿位涡和垂直螺旋度在暴雨数值预报中的应用研究

文章利用湿位涡(MPV)不可渗透性原理、湿位涡垂直分量(MPV1)、湿位涡水平分量(MPV2)和垂直螺旋度对2004 08 26T12:00UTC~2004 08 28T12:00UTC 发生在我国中东部一次典型的大到暴雨过程进行了诊断分析.结果表明,通过分析每日00:00UTC850hPa上的 MPV1、MPV2和700hPa上的垂直螺旋度,发现凡是出现垂直螺旋度的相对大值区、MPV1正值和 MPV2负值三者重叠的区域,则都是降水的大值区;在700hPa上,湿位涡高值区对应地面上的降水区,MPV 异常高值区与等θe 线配和在我国中东部暴雨中有很好的指示性;MPV1、MPV2的正负重叠区,但不是垂直螺旋度的大值区,则有可能不出现降水或少量降水.

Application of moist potential vorticity and vertical helicity in numerical weather prediction of torrential rain

A typical torrential rain event that occurred in the central and eastern China form August 26 to August 28,2004 at 12:00 is conducted.At the same time,impermeable principle of moist potential vorticity(MPV),the vertical component of moist potential vorticity(MPV1),the horizontal component of moist potential vorticity(MPV2) and vertical helicity are used to diagnostic analysis.By analyzing the daily 00:00 UTC MPV1 and MPV2 at 850 hPa and vertical helicity at 700 hPa,we find that there is the heavy precipitation which located to relatively big value of three overlapping areas of vertical helicity,positive MPV1 and negative MPV2.At 700 hPa,MPV high-value area corresponds to the precipitation area on the ground,and there is a good indication of heavy rain in the central and eastern China if MPV high-value area matches with equivalent potential temperature line.Overlapping areas of positive MPV1 and negative MPV2 that is not the big value area of vertical helicity may be no or little precipitation.