安顺地区暴雨日数年际变化的气候特征

利用1979—2009年31 a安顺地区（安顺、平坝、普定、镇宁、关岭和紫云）6站的降水资料,统计分析6站暴雨日数和暴雨量的变化特征,提取代表安顺地区的代表站,对其进行统计分析,得到安顺地区暴雨日数年际变化的气候特征。安顺地区暴雨日数的在20世纪80年代末—90年代末期间具有明显的3～5a的年际震荡,并在90年代初达到峰值。安顺地区暴雨偏多年在高低空环流、风场和能量场配置的主要特征为：700hPa和500hPa高低空位势高度配置一致,位势高度在中高纬度出现＂东高西低＂的走势,安顺地区位于异常低涡的东南部,西太平洋副热带高压的西部,这样来自异常低涡东南侧的冷空气与来自海洋北上的暖湿气流在此交汇,利于底层切变线和准静止锋的建立;安顺地区位于高空偏西急流的右前方的出口处,低空西南急流右前方的出口处和低空东南急流左前方的出口处,这种高低空急流的配置非常有利于暴雨区垂直上升运动的产生;安顺地区及其附近区域对流不稳定较强,利于对流不稳定能量的积累,从而使对流不稳定区域易出现强对流系统,对安顺地区的不稳定能量的储存和释放十分有利。

Interannual variation of rainfall days'climatic characteristics

This paper has analysised the climatic characteristics of the rainstorm days in the AnShun region,used by the precipitation data of six ground observation stations(AnShun,PingBa,PuDing,ZhenNing,Guanling and ZiYun) in order to choose the stations which could represent the AnShun region.The rainstorm days has 3~5 years interannual period from the late of the 1980s to the late of the 1990s in AnShun region,and this change peaks in the early of the 1990s.The main features of Climatic Characteristics of Interannual Variability of the rainstorm days in the AnShun region: the configuration the abnormal potential height at 500hPa and 700hPa are consistent,and showed the pattern of which is high in the east and is low in the west.AnShun located in the southeast of the abnormal low vorticity and located in the west of the west Pacific sub-tropic high,in favour of the cold air form the southeast of the abnormal low vorticity and the warm-moist air flow located from the west of the west Pacific sub-tropic high gathering in the place,and then in favour of the low level shear and quasi static font building;The AnShun region located the right of the export of westly jet stream in high level,the right of the export of southwestly jet stream and the left of the export of southeastly jet stream in low level,the configuration maked for the vertical rising motion in the rainstorm region;the region around GuiZhou is convection instability,which is helpful for the energy of the instability saving and releasing.