1967—2017年兴安盟暴雨时空分布特征分析

利用1967—2017年近51a兴安盟8个国家级气象观测站的逐日降水资料,采用线性倾向估计、11a滑动平均和EOF分解等统计方法,对当地暴雨的气候特征、暴雨的年际和年代际变化以及暴雨的时空演变特征进行分析,结果表明:(1)兴安盟暴雨日数的中心轴线呈南北走向,正好位于西风带上大兴安岭的背风坡沿线;而暴雨雨量大值区域主要位于东部,由蒙古高原向松辽平原过渡的低海拔地区。(2)近51a来兴安盟暴雨日数呈减小的负增长趋势,并经历了偏少—显著偏多—显著偏少—偏多4个阶段。(3)暴雨日数EOF分解前两个模态可以代表兴安盟暴雨日数空间分布类型的一半以上,依次表现为全盟一致型和东—西反向型。

Analysis of Spatial-Temporal Distribution Characteristics of the Rainstorm in Hinggan League from 1967 to 2017

Based on the daily precipitation data of 8 national meteorological stations in Hinggan League in the past 51 years from 1967 to 2017,the statistical methods of linear tendencies estimation,11 years moving average and the EOF analysis are used to research the climatic characteristics,the interannual and interdecadal changes and the spatial-temporal distribution characteristics of rainstorm in Hinggan League.The results show as follows.(1)Central axis of rainstorm days runs north to south in Hinggan League,which is along with the leeward slope of Da Hinggan Mountains on the westerlies.The large value area with storm rainfall is mainly located in the east which is the low-altitude transition region from Mongolia plateau to Songliao Plain.(2)The rainstorm days show a decreasing negative growth trend and experience four stages of less than normal-significantly more than normal-significantly less than normal-more than normal in Hinggan League.(3)The first two modes of EOF analysis for rainstorm days can represent more than half of the spatial distribution types in Hinggan League.The first mode is uniform type and the second mode is east to west reverse type.