【摘要】 利用全国160站逐月降水资料,统计分析了1951~2000年50年华南前汛期降水、江淮梅雨和华北雨季旱涝事件的分布特征,结果表明:近50年无论是华南前汛期降水、江淮梅雨还是华北雨季,旱(涝)事件频率相当,华南和江淮洪涝强度大于干旱强度,华北干旱与洪涝强度相当,华南前汛期降水和华北雨季总体呈趋旱的趋势,而江淮梅雨呈趋涝的趋势;华南前汛期降水年际变化最为显著,江淮梅雨次之,华北雨季最弱,年代际变化的情况正好相反;从同期500 hPa高度场来看,华南前汛期降水多少与其北侧有无低值系统向南发展关系密切,江淮梅雨和华北雨季均与副高相关显著,不同在于前者还和鄂霍茨克阻塞高压呈显著正相关,而后者受其西北侧中高纬地区的环流影响较大;从前期海温来看,华北雨季与大西洋西部和北太平洋海温关系比华南前汛期降水和江淮梅雨更为密切,江淮梅雨与中国近海海温相关关系最为显著,而华南前汛期降水与孟加拉湾附近海温相关最明显。更多还原

【Abstract】 Based on the Chinese 160 stations monthly precipitation supplied by the National Meteorological Information Center of China,the distribution features of floods and droughts events during the first flood period in South China,the Meiyu period in the middle and lower reaches of the Yangtze River and the Huaihe River valleys and the rainy season in North China are analyzed respectively and compared with each other by using the droughtsfloods indices for the period of 19512000.The interannual and decadal variations of the three types of rainfall are also investigated by the DB-16 wavelet analysis method.The correlation analysis is applied in finding the features of the atmospheric circulation in the same term and sea surface temperature(SST) in the preceding months which are linked with different kind of rainfall.Results show: in the last 50 years,the frequency of floods events is nearly the same as that of the droughts,and the intensity of floods is greater than that of droughts in South China and the Yangtze River and the Huaihe River valleys,whereas North China has the similar intensity of floods and droughts,associated with a drought tendency in South China and North China and a flooding tendency in the Yangtze River and the Huaihe River valleys;the first flood period in South China has the most remarkable annual variation,the Meiyu has the second and the rainy season in North China has the weakest,but the decadal variation is just opposite;according to the 500 hPa height field of the same term,the first flood period of South China has a close relationship with the low value systems at its north side while the Meiyu and the rainy season in North China are greatly influenced by the western Pacific subtropical high.The Meiyu also has a significant positive correlation with Okhotsk Blocking High and the rainy season in North China is mainly affected by the circulation systems on its northwest side;the rainy season in North China is closely related to the SST in Atlantic and North Pacific,while the SST in the adjacent sea of China has a strongest influence on the Meiyu of the Yangtze River and the Huaihe River valleys and the first flood period in South China has the most tremendous relationship with the SST near the Bay of Bengal.The emphasis of this paper is concentrated on the features summary of the three types of rainfall in East Asia.The East Asian summer rainfall is a very complex phenomenon and very important for the agriculture,industry and people’s life.This work attempts to offer some references for the prediction of the East Asian summer monsoon rainfall.更多还原