近40a呼伦贝尔市暴雨时空变化特征分析

Spatial and temporal change characteristics of rainstorm over Hulun Buir in the recent 40 years

使用呼伦贝尔市16个国家气象观测站1971—2010年逐日降水资料,分析了近40 a呼伦贝尔市暴雨次数和暴雨量的时空变化特征。结果表明:该市暴雨具有我国东北地区暴雨的特征,即局地单站暴雨发生最频繁(占81.3%),其次是区域性暴雨(占13.3%),连续暴雨发生频次较低;该市暴雨次数和暴雨量年际变化趋势一致,并在时间序列上均存在一致的3个时期:20世纪70年代初暴雨较少期、20世纪70年代末到90年代末暴雨较多期、21世纪初暴雨较少期;该市暴雨开始于5月,结束于9月,主要出现在夏季,集中在7下旬,8月上旬次之;暴雨总量沿大兴安岭山脉自西北向东南方向递增,大兴安岭东面暴雨总量明显大于大兴安岭西面,说明地形对呼伦贝市暴雨作用显著。

Spatial and temporal change characteristics of rainstorm frequency and rainstorm precipitation over Hulun Buir in the recent 40 years are analyzed by using daily precipitation data from 1971 to 2010 at 16 meteorological stations in Hulun Buir area.The results show that rainstorm over Hulun Buir area presents the characteristics of rainstorm over Northeast China.The single station local rainstorms occur frequently accounting for 81.3% of the total frequency in the area,the regional rainstorms account for 13.3% of the total,and a few continuous rainstorms happen.Both rainstorm frequency and rainstorm precipitation have the identical interannual change trends and 3 consistent change periods,that is,less rainstorm period in the early 1970s,more rainstorm period from late 1970s to the early 21st century and less rainstorm period after the early 21st.In the area the first rainstorm event occurs in May and the last one occurs in September usually.The rainstorm events happen mainly in summer and most of them in the last ten-day period of July and the first ten-day period of August.The amount of rainstorm shows an increasing trend along Daxing’an Ling Mountains from northwest to southeast,and the amount of rainstorm on the east of Daxing’an Ling Mountains is significantly more than those on the west of Daxing’an Ling Mountains,which shows that the effect of topography on rainstorm events in Hulun Buir area is remarkable.