广西夏季降水的多时间尺度特征及影响因子  

The Multi-timescale Features for Guangxi Summer Precipitation and the Related Predictors

作　　者：覃志年[1] 胡娅敏[2,3] 陈丽娟[4] 

机构地区：[1]广西壮族自治区气候中心,南宁530022 [2]广东省气候中心,广州510080 [3]广东省广州市气候与农业气象中心,广州510080 [4]国家气候中心中国气象局气候研究开放实验室,北京100081

出　　处：《应用气象学报》2013年第5期565-575,共11页Journal of Applied Meteorological Science

基　　金：国家自然科学基金青年基金项目(40905043);广州市科技计划项目(2010Y1-C031);广西自然科学基金项目(2011GXNSFA018002);国家重点基础研究发展计划项目(2013CB430203);中国气象局气候预测创新团队项目

摘　　要：利用1951—2011年广西夏季降水站点资料和NCEP/NACR等多种再分析资料,通过相关分析、经验模态分解、统计检验分析了广西夏季降水的多时间尺度特征及其影响因子,利用多元线性回归方法对夏季降水进行拟合和预测试验。结果显示:广西夏季降水具有多时间尺度特征,不同时间尺度对应着环流因子不同时间尺度的分量;在准2年尺度上,主要影响因子为季风槽、低空急流、高空急流、贝加尔湖高度场、南印度洋东部海温。利用对广西夏季降水影响显著的环流因子本征模态函数分量和多元线性回归方法拟合夏季降水,相关系数为0.73,表明广西夏季降水是环流因子多时间尺度共同作用的结果。利用前期冬季南印度洋东部海温异常本征模态函数作为前兆因子预报广西夏季降水,6个独立样本检验显示预测与实况趋势一致,该工作可供利用多时间尺度信息进行区域气候预测参考。Based on NCEP/NACR reanalysis data and Guangxi summer precipitation （GSP） station data, using the correlation analysis, composite analysis, empirical orthogonal function （EOF）, empirical mode decom- position （EMD）, abrupt change test and the statistic significant test methods, GSP multi-timescale charac- teristics and their related circulation as well as the external forcing features are analyzed. According to the diagnostic analysis, the fitting and the prediction equation of GSP are proposed by the multivariate linear regression method. GSP is mainly influenced by the mid-latitude height field anomaly in Lake Baikal region, the subtropical high and monsoon trough （MonTr） in the subtropical region, the low level jet （LLJ） and upper level jet （ULJ） in the same season, as well as the sea surface temperature （SST） anomaly in the eastern of the South Indian Ocean in the pre-winter and prespring. The possible physical concept model for GSP is that, when MonTr, LLJ, and the easterly to the south of the subtropical high （ESTH） occur at 850 hPa wind field, the blocking high （BH） over Lake Baikal at 500 hPa poten- tial height, as well as ULJ over South China at 200 hPa wind field are stronger （weaker） than normal, andthe subtropical high ridge location is northward （southward） to its normal position, the rainfall is more. The influ- ences of circulation may impact summer rainfall anomaly through the muhi-timescale features. Using EMD method, there are 5 principle modes for the summer rainfall. The variance contributions from the first to the fourth intrinsic mode function （IMFI--IMF4） are 55~, 18~, 12~ and 12~, respec- tively. The periods over the statistic significant test are quasi-2 years, 7.6 years, 12.7 years and 19 years. On the scale of quasi-2 years, the summer rainfall is affected by the corresponding IMF1 components of the MonTr, LLJ, ULJ, BH over Lake Baikal, SST anomaly in the east of the South Indian Ocean. The sum- mer rainfall has high relationship with th

关 键 词：夏季降水 多时间尺度 经验模态分解 本征模态函数 

分 类 号：P426.6[天文地球—大气科学及气象学]