浙江西北部山地暴雨特征

Characteristics of rainstorm in northwestern mountainous area of Zhejiang

利用2005-2017年14个自动气象站和2015-2017年66个自动气象站的降水资料,对浙西北暴雨的时空分布特征进行了分析,发现浙西北雨量分布呈西南、东北多,中部、东部少的特征,有2个暴雨中心,一个是位于清凉峰到大明山一带的梅汛期暴雨中心,另一个为天目山北部市岭一带的台风暴雨中心;暴雨存在明显的月、日变化特征,7-8月暴雨最多,春雨期暴雨主要出现在日落后,梅雨期主要出现在早晨前后,其次是午后,盛夏时主要出现在午后;6月前暴雨集中在西部、南部,7月出现明显转折,西南暴雨迅速减少,东北部天目山市岭一带暴雨明显增多。市岭地形为东北-西南河谷型,受狭管效应和地形抬升的影响,当台风位于天目山东南部时,天目山一带吹东北风对降水增幅最明显。

In order to analyze the effect of terrain on precipitation, the spatial and temporal distribution characteristics of rainstorm in northwest Zhejiang are analyzed by using 14 automatic meteorological stations during 2005 to 2017 and 66 automatic meteorological stations during 2015 to 2017. The results showed that the rainfall in northwest Zhejiang was more in the southwest and northeast part and less in the east part as a whole, there were two rainstorm centers, one was the meiyu rainstorm center located in the Qingliang Peak to Daming Mountain area, and the other was the typhoon rainstorm center in the north of the Tianmu Mountain. Besides,the daily and monthly changes of rainstorm were obvious. The rainstorms concentrated from July to August, in the spring rain period it mainly occurred after sunset, while in the meiyu period mainly occurred in the morning, and in the summer was mainly occurred in the afternoon. From the spatial distribution point of view,rainstorms were concentrated in the west and south before June. There were obvious turning points in July. The rainstorms in the southwest were rapidly reduced, and in the northeastern Tianmu Mountain were obviously increased. In addition,the terrain had an obvious increase in different precipitation systems. The west wind belt system was most likely to produce heavy rain in the Qingliang Peak area. The typhoon had the greatest impact on the Tianmu Mountain area. The northeast wind in Tianmu Mountain had the most obvious increase in precipitation.