华东地区近50年降水量的变化特征及其与旱涝灾害的关系分析

CHARACTERISTICS OF RAINFALL VARIATION OVER EAST CHINA DURING THE LAST 50 YEARS AND THEIR RELATIONSHIPS WITH DROUGHTS AND FLOODS

利用华东及周边地区113个气象站近50年的降水量资料计算了该地区降水量集中度和集中期,分析了华东地区降水量、降水量集中度和集中期的气候特征和变化趋势特征。结果表明,华东地区北部的降水量集中度明显高于南部地区,而南部地区降水量集中期超前于北部地区1个半月左右,体现了华东地区降水量时空分布上显著的地区差异。随着全球气候变暖,华东地区降水量有增加的趋势,降水量集中度无明显的变化趋势,降水量集中期有普遍推后的变化特征,主要表现在江西和河南南部。华东地区的降水量与降水量集中度和集中期有密切的关系,表现在降水量偏多的年份里,通常降水量集中度越强其降水量集中期偏迟。从年际变化看华东地区降水量时空的不均匀分布,导致降水极端事件频繁发生,是近年来旱涝灾害增多的一个原因。

With the precipitation data from 113 stations in East China during the last 50 years, the characteristics of the precipitation, including Precipitation Concentration Degree （PCD） and Precipitation Concentration Period （PCP） and their tendencies, are analyzed. The results show that the PCD in the northern part of the region is markedly higher than that in the southern part, but the PCP in the south is much earlier than that in the north by about one and a half months, which displays significant regional differences in precipitation. With the global wanning, precipitation over East China shows an increasing tendency, but PCD displays a trend that is neither increasing nor decreasing. At the same time, the PCP is later than before, which can be mainly found in Jiangxi and southern Henan provinces. As a result, there are strong associations between the precipitation, PCD and PCP, which can be shown in the years with more precipitation, usually, the higher the PCD, the later the PCP is. In a word, the abnormal distribution of precipitation, PCP, and PCD over East China results in more extreme events of precipitation and more droughts and floods.