三峡库区汛期极端降水非均匀性特征  

INHOMOGENEITY CHARACTERISTIC OF EXTREME PRECIPITATION IN THE FLOOD PERIOD OF THE THREE GORGES RESERVOIR AREA

作　　者：张天宇[1] 李永华[1] 程炳岩[1] 孙杰[2] 许崇海[3] 

机构地区：[1]重庆市气候中心,重庆401147 [2]武汉区域气候中心,湖北武汉430074 [3]中国气象局气象探测中心,北京100081

出　　处：《长江流域资源与环境》2011年第3期298-304,共7页Resources and Environment in the Yangtze Basin

基　　金：重庆市自然科学基金计划重点项目(CSTC;2008BA0022)"三峡库区成库后极端气候事件的研究";中国气象局项目"重庆三峡库区气候效应监测评估研究";重庆市气象局科技计划项目"<重庆市气候业务技术手册>相关科学技术研究";中国气象局气候变化专项"全球变暖背景下三峡库区极端天气气候事件趋势预估研究"

摘　　要：利用极端降水量集中度和集中期讨论三峡库区汛期极端降水量的非均匀性分布特征。结果表明:三峡库区极端降水量空间分布表现为西南部和东北部地区相对较少,中部、东南部相对较多。库区汛期极端降水集中度和集中期的空间差异不大,集中程度总体较差,东北部和西部地区极端降水相对集中,中部相对分散。库区极端降水主要集中在6月底和7月上中旬,东北部和西部偏西地区集中期相对较晚,中部地区集中期相对较早。库区汛期极端降水量的分配状况与同期极端降水量存在较好的关系,即极端降水量越少,则极端降水量越集中、集中期越早;反之极端降水量越多,则极端降水量越分散、集中期越晚,尤其是在库区东北部地区最为显著。三峡库区蓄水后极端降水集中程度在空间上一致性较好,表现为蓄水后更为分散;极端降水量和集中期则在空间上差异显著,大致表现为蓄水后东北部极端降水增加并延迟;西南部极端降水减少并提前。With the daily precipitation data derived from 35 weather stations in the Three Gorges Reservoir Area from 1960 to 2008, the extreme precipitation threshold for different stations were defined by centesimal value method, and then the concentration degree and the concentration period were calculated to indicate the temporal distribution features of extreme precipitation. Based on the two new indices,inhomogeneity of extreme precipitation in the Three Gorges Reservoir Area was analyzed. The results showed that there was less extreme precipitation in southwestern and northeastern parts but more in central and southeastern parts. A little discrepancy appeared for the spatial distribution between concentration degree and concentration period of extreme precipitation. The extreme precipitation events happefied more frequently in northeastern and western parts than in central part relatively. The period of accruing extreme precipitation in the Three Gorges Reservoir Area was usually from the end of June to July 15th,and it was later in northeastern and western parts while earlier in central regions. The concentration degree and the concentration period of extreme precipitation showed a positive correlation with the amounts of extreme precipitation in flood season. If the amounts of extreme precipitation were less, the concentration degree was higher and the concentration period was earlier especially in the northeast parts, vice versa. After impound of the Three Gorges Reservoir,the concentration degree was uniform in different parts for whole area, but some obvious changes happened for concentration period and the amounts of extreme precipitation. More extreme precipitation appeared and the concentration period was earlier in the northeastern parts, while what happened in the southwestern parts was reversed.

关 键 词：三峡库区 极端降水 集中度 集中期 

分 类 号：P642.22[天文地球—工程地质学]