中国东部夏季极端降水统计特征及其与El Nino的关系
投稿时间: 2015-10-27  最后修改时间: 2016-01-10  点此下载全文
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作者单位E-mail
余锦华 南京信息工程大学 jhyu@nuist.edu.cn 
祁淼 南京信息工程大学  
孙齐颖 南京信息工程大学  
基金项目:国家重点基础研究发展计划(973计划)
中文摘要:选取中国东部夏季5~9月无缺测429站1961~2012年逐日降水资料,利用广义帕雷托分布(GPD)拟合,研究中国东部52年以及El Nino发展和衰减年极端降水的统计特征,并分析其成因。结果表明:(1)中国东部阈值呈由东南向西北递减的态势,且基本为线性增加趋势。(2)华南地区尺度参数最大,出现极端降水的概率大。黄河以南地区尺度参数变化趋势正值较多,出现极端降水的概率增加。(3)El Nino发展年夏季,西太平洋上有气旋环流异常,中国东南部受气旋西侧的异常偏北气流影响,多地阈值偏小,只有福建东南部及黑龙江中西部易发生破纪录的极端降水。(4)El Nino衰减年夏季,西太平洋上为异常反气旋环流,中国东南部受反气旋西侧的异常偏南气流影响,多地阈值偏大,广东中东部及皖鄂赣交界发生洪涝灾害的可能性增大。
中文关键词:极端降水  统计特征  El Nino
 
Statistical Characteristic of Summer Extreme Rainfall and Its Relation with El Nino over Eastern China
Abstract:Based on the daily rainfall data from 1961 to 2012, 429 stations with no missing chosen from May to September over Eastern China are introduced to the Generalized Pareto Distribution (GPD) to study the spatial distribution of extreme rainfall statistical characteristic in 52 years, as well as in El Nino developing and decaying years. The cause is also discussed. The results show that: (1) The thresholds decrease from southeast to northwest, and the trends of thresholds are basically positive over Eastern China. (2) The largest values of scale parameter are in South China, which means there are high probabilities of maximum rainfall. The trends of scale parameter are positive in most places to the south of the Yellow River. And the probabilities of maximum rainfall are increasing in these places. (3) In the summer of El Nino developing years, there is cyclone circulation anomaly in the western Pacific. And the Southeast China is under the influence of north wind anomaly on the west of the cyclone, which leads to less rainfall in most places over Eastern China. There have more probabilities of record-breaking maximum rainfall only in southeastern Fujian and west central Heilongjiang. (4) In El Nino decaying years, there is anticyclone circulation anomaly in the western Pacific. And the Southeast China is under the influence of south wind anomaly on the west of the anticyclone, which leads to more rainfall. The probability of severe flooding disaster is large in east central Guangdong and at the junction of Anhui, Hubei, and Jiangxi.
keywords:extreme rainfall  statistical characteristic  El Nino
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