【摘要】 利用东北三省和内蒙古东部200个测站1961～2005年的逐日降水资料,分析了东北地区夏季暴雨的空间分布特征和时间演变规律,以及各类暴雨与各种影响天气系统之间的气候统计关系。结果表明,在空间分布上,暴雨由东北地区的东南部向西北部递减的地域特征十分明显,绝大多数大范围和区域性暴雨一般都集中出现在东北地区的南部和中部,而局地暴雨的分布范围相对较广,地域差别也较小。在时间分布上,几十年来东北地区暴雨的阶段性变化特征十分明显,多暴雨和少暴雨的出现具有11～12年左右的低频变化周期。20世纪80年代初以来,暴雨日出现的年际变率有明显增加的趋势,特别是20世纪90年代中期以后,东北地区暴雨发生的次数虽然明显减少,但平均每个暴雨日的暴雨量却有所增加。在东北地区出现的局地暴雨中,以北方天气系统的影响贡献最大,而在区域性暴雨和大范围暴雨中,南方天气系统影响的比例明显增加。更多还原

【Abstract】 By using the daily precipitation data at 200 stations in the northeastern part of China from 1961 to 2005,the characteristics of the spatial and temporal distributions of the summer hard rain in the northeastern part of China and the relationship between the different types of the hard rain and the different influencing synoptic systems are studied. The results show that the spatial differences of the hard rain distribution with more rainfall in the southern and eastern parts,and less rainfall in the western and northern parts over the northeastern part of China are very significant. The majority of the regional-scale and widespread hard rains mainly occur in the southern and middle parts of the northeastern part of China generally,whereas the local-scale hard rain is of wide distribution,and its spatial difference is also relatively small. The hard rain over the northeastern part of China has a significant 11-12-year low-frequency variation period. Since the early 1980s,the interannual variability of the hard rain has had the increasing tendency. Especially after the middle 1990s,the frequency of the hard rain has decreased obviously,but the intensity of the hard rain on the average has increased to some extent. The great majority of the local-scale hard rain are mainly caused by the northern synoptic systems,however the southern synoptic systems related with the low-latitude and subtropical areas contribute greatly to the regional-scale and widespread heavy rain in the northeastern part of China.更多还原