摘要
In order to explore the relationship between heavy precipitation and the distribution characteristics of wet potential vorticity field,based on the NCEP 1°×1°6-hour reanalysis data,the wet potential vortex field in a heavy precipitation weather process in the central-southern part of Inner Mongolia was analyzed through the analysis of weather situation and calculation of vertical component(MPV_(1))and horizontal component(MPV_(2))of wet potential vortex(MPV).The results show that this heavy precipitation was a heavy precipitation weather process under the combined action of the cold air behind the trough and the southwest warm and humid airflow.The diagnostic analysis of θ_(se) shows that the south side of the area where the cold and warm air met before the precipitation was a high-temperature and high-humidity area,where a large amount of unstable energy was gathered,and the heavy precipitation occurred in the area with the most dense θ_(se) lines.This heavy precipitation process was dominated by the release of convective unstable energy in the lower troposphere,the positive pressure term of wet potential vortex MPV 1 was smaller than 0 in the lower troposphere and larger than 0 in the middle and upper layers;the positive-value wet potential vortex was transported to the lower layer,which was conducive to the release of unstable energy,so that precipitation increased.The negative-value center of wet potential vortex in the middle and low layers corresponded well to the heavy precipitation area,and the precipitation intensity and duration were consistent with the increase and enhancement time of the negative-value area of MPV_(1).The positive-value area of MPV_(1) was 6-12 h earlier than the heavy precipitation area,which has good indication significance for the prediction of the heavy precipitation area.In the lower troposphere,the configuration of MPV_(1)<0 and MPV_(2)>0 can be used as the basis for judging the location of precipitation center.
