甘肃省短时强降水的时空特征

The Spatial and Temporal Distribution Characteristics of Short-duration Heavy Rainfall in Gansu Province

基于甘肃省81个自动气象站2002—2012年逐小时降水数据,分析了甘肃省近11 a来短时强降水的时空变化特征。结果表明:短时强降水频次自甘肃省西北向东南逐步递增,陇东南地区是甘肃省短时强降水发生频次最多、强度最强的地区。短时强降水存在2个高发中心,一个在以合水为中心的陇东地区,另一个在以徽县为中心的徽成盆地。短时强降水主要发生在午后至前半夜,出现时段集中在16:00—00:00,17时前后是短时强降水天气高发时段。短时强降水主要出现在5—9月,其中7—8月是一年中出现最多的月份,其次是6月。近11 a来,短时强降水频次呈上升趋势,2006年和2010年出现了2个峰值,其中2010年最多,发生52次,2004年最少只有17次。

Short-duration heavy rainfall （SDHR）forecasting is important and difficult of severeconvective weather forecasting. A severer disaster can be brought by SDHR in the arid and semi-arid area, especially in Gansu Province. Based on the hourly precipitation data from 81 stations inGansu Province during 2002 -2012, the spatial and temporal variation characteristics of SDHR werestudied . The results showed the occurring frequency of SDHR gradually increase from thenorthwest to the southeast, SDHR is the most intensive in the southeast parts of Gansu Province.There are two centers of high value, and one is in Heshui County, located in eastern parts of GansuProvince, another is in Huicheng basin located in Hui County. SDHR is concentrated in May toSeptember, especially in July and August. The inter -annual variations of SDHR showed that thefrequency of SDHR increased from 2002 to 2012, and with peaks in 2006 and2010. SDHR occurredmost frequently in 2010 with 52 occurrences, and only occurred 17 times in 2004. SDHR mainlyoccurred at night, especially at the early night, concentrated in the period between 16：00 to 00：00,with high-incidence time around 17：00.