【作者】 李爱华；

【导师】 江志红；

【作者基本信息】 南京信息工程大学 ， 气象学， 2005， 硕士

【摘要】 本文利用中国东部地区355站的逐日降水资料,以及NCEP/NCAR提供月平均海温和高度场资料,采用扩展EOF、旋转EOF、墨西哥帽小波分析、合成分析、滑动-t检验、低通滤波等方法研究了我国东部夏季雨带推进过程和各区域夏季降水季节演变的年际、年代际变化特征及其两者的关系,在此基础上进一步分析了雨带推进强弱的海气背景特征,得出的主要结论如下: 1、空间均一化降水指数EEOF展开的第一特征向量反映了中国东部夏季雨带推进的多年平均状态,对应的时间系数表示雨带推进强度的变化。110°E线将整个东部的雨带分成了东、西侧两条雨带,此两条雨带推进进程不一致导致整个东部雨带呈东北西南方向向北推进。雨带的推移强度具有4～6年、10年、15年的周期,且在50年代后期到60年代中期,雨带的推进强度偏强,80年代最弱,表现了雨带推进强度的准15年周期变化。并且进一步得出当雨带推进强年,降水主要集中在华南、长江流域及其华北、东北地区,夏季多出现Ⅰ类雨型,而黄淮地区降水偏少,雨带推进弱年相反,黄淮地区的降水偏多,夏季多出现Ⅱ、Ⅲ类雨型。 2、根据中国东部夏季雨带推进的过程及其东部降水的季节演变特征,利用REOF方法分析空间均一化指数将中国东部的降水分成了四个区域:华南、长江流域、黄淮地区和华北东北地区。并进一步指出,夏季雨带推进强度与华南、长江流域和华北东北地区的夏季降水呈正相关,而与黄淮地区的夏季降水呈负相关,并且其相关程度在年代际尺度上的相关性要比年际尺度上的相关性显著。在年际尺度上与华北东北地区降水的正相关非常显著,而在年代际尺度上与华南、华北东北地区夏季降水的正相关与黄淮地区夏季降水的显著负相关,其显著性程度均通过了99%信度检验,而与长江流域夏季降水的正相关性较差。 3、在年际尺度上,夏季雨带的推进强度与前一年的冬季和同年春季夏季的低纬度中太平洋地区海温呈显著正相关,而与前一年的夏季和秋季西太平洋的海温呈显著负相关,与前一年的夏季、秋季和冬季赤道东太洋海温呈正相关而到同年夏季转化为负相关关系。在年代际尺度上,雨带推进强度与前一年的秋、冬季和同年春季西太平洋的负相关最为显著,与前一年夏季和同年夏季的低纬度中太平洋和中纬度东北太平洋海温呈显著正相关;与140°W以西的赤道东太平洋海温呈正相关,而与前一年秋、冬季140°W以东的赤道东太平洋地区的海温为显著负相关。夏季、秋季西太平洋异常偏冷(暖),赤道东太平洋的东部地区异常偏暖更多还原

【Abstract】 Using daily precipitation data of 355 stations over eastern China and sea temperature &. height field data offered by NCEP/NCAR, and many methods such as EEOF, REOF, Mexico wavelet analysis, synthesized analysis, move-t test, this paper studied the interannual and interdecedal of varieties of summer rain belt’s movement and seasonal precipitation change of each area .further analysed the correlations between the two former and corresponding characters of height and Sea temperature. Primary conclusions as follows:Firstly, Summer rain belt is divided into two centers by 110°E line, and their inconsistent propagation speed lead to rain belts propagation to north by way that from northeast to southwest. Rain belts propagation has interdecedal and interannual change. During the strong propagation year, the positive anomaly of precipitation would appear in the north of China, always corresponding I rainfall Pattern, during the weak propagation years, the rain belt appear in south of China, corresponding II or III rainfall Pattern. Further the intensity of their movement have two obvious breaks in 1966 and 1979,so rain band propagate strong during 1957-1966,but weak during 1979-1989.Secondly, eastern China is divided into four areas based on seasonal evolvement characters of Summer rainfall over eastern China and the character of summer rain belt’s propagation. And The intension of rain belt’s movement has positive correlation with precipitation of South China, Changjiang river valley and areas north to yellow river in Summer, but has negative correlation with Huanghuai area. In the interannual variety it has only obvious positive correlation with the rainfall of north area of yellow river, but in interdecadal variety scale it has obvious positive correlation with the rainfall over South China and north areas to yellow river and has obvious negative correlation with the rainfall of Huanghuai area. The correlation is more obvious in interannual variety scale than in interdecadal variety scale.Thirdly, In interannual scale, the intensity of rain belt’s movement have marked positive correlation with SST at middle pacific in the low latitude and northease pacific area in middle latitude and obvious negative correlation with SST of west pacific in the last summer and lastAutumn. The positive correlation with east Pacific around equator during from the last summer to last winter change to negative correlation in the summer. The correlation between sea temperature and the intensity of rain belt’s movement is better in interdecedal scale than in interannual scale. Only difference is that 140° w divide east Pacific into positive (west to 140° w) and negative (east to 140° w) parts form last Summer to last Winter. The SST of east Pacific around equator is anomaly worm (cold) from summer to winter in the last year when summer rain belt propagation is strong (weak).But in the same year SST in that areas is anomaly cold(warn),that show the correlation between the intensity of rain belt’movement and SST of east Pacific around equator has two years change period. When SST of east Pacific is anomaly warm (cold) ,Summer rain belt propagates strongly (weakly) next summer, it often happens I or EH (II or III) rain pattern.Fourthly, the weak year of rain belt’propagation, west Pacific High is morn north than orderly years in starting summer ,but morn south in matured summer. In the strong year of rain belt’propagation, west Pacific High is morn south than orderly years in starting summer but morn north in matured summer. In whole Summer, there is negative (positive) height anomaly over middle and low latitude,, so rain belt propagates more north (south).更多还原