山西省汛期短历时强降水特征

Characteristics of Short Duration Heavy Rainfall During Flood Season in Shanxi Province

基于山西省2011—2016年汛期290个自动气象站逐时降水资料,结合本地强降水预警业务规定,按照致灾风险程度将短历时强降水分为四级,并分析了各级短时强降水的时空变化特征。结果表明:短时强降水主要受地形影响,山西各级强降水的累计降水量和降水时数大值区一般沿太行山脉和吕梁山脉分布;短时强降水主要集中在7—8月,15—18时(北京时,以下同)为高发时段,第二峰值出现在20—23时,一般性强降水在7月的上午时段还存在一个峰值;城区一般性强降水比乡村区域偏多偏强,特强降水城市化影响作用不明显。

Based on the hourly precipitation data of 290 automatic weather stations in Shanxi province during flood season from 2011 to 2016,and combined with the regulations of locally early warning service of the heavy precipitation,this paper divides the short duration heavy precipitation into four levels according to the degree of disaster risk,and analyzes the spatial-temporal variation characteristics of the heavy rainfall at all levels comprehensively in Shanxi province. The results show that the short duration heavy rainfall depends on topography,and the areas with more cumulative precipitation and longer precipitation hours at all levels are generally distributed along Taihang Mountains and Lüliang Mountains. The short duration heavy precipitation mainly occurs in July and August,with a high frequency period at 15:00 to 18:00 LST,and the second peak appears at 20:00 to 23:00 LST. In addition,there is a peak value of general heavy precipitation in the morning of July.The general heavy precipitation in urban areas is more and stronger than that in rural areas,while the urbanization effect of extra heavy rainfall is not obvious.