CHARACTERISTICS OF MEI-YU PRECIPITATION AND SVD ANALYSIS OF PRECIPITATION OVER THE YANGTZE-HUAIHE RIVERS VALLEYS AND THE SEA SURFACE TEMPERATURE IN THE NORTHERN PACIFIC OCEAN

Based on the precipitation data of Meiyu at 37 stations in the valleys of Yangtze and Huaihe Rivers from 1954 to 2001, the temporal-spatial characteristics of Meiyu precipitation and their relationships with the sea surface temperature in northern Pacific are investigated using such methods as harmonic analysis, empirical orthogonal function (EOF), composite analysis and singular value decomposition (SVD). The results show that the temporal evolution and spatial distribution of Meiyu precipitation are not homogeneous in the Yangtze-Huaihe Rivers basins but with prominent inter-annual and inter-decadal variabilities. The key region between the anomalies of Meiyu precipitation and the monthly sea surface temperature anomalies (SSTA) lies in the west wind drift of North Pacific, which influences the precipitation anomaly of Meiyu precipitation over a key period of time from January to March in the same year. When the SST in the North Pacific west wind drift is warmer (colder) than average during these months, Meiyu precipitation anomalously increases (decreases) in the concurrent year. Results of SVD are consistent with those of composite analysis which pass the significance test of Monte-Carlo at 0.05.     

近50年来全球海温异常对我国东部地区冬季温度异常影响的诊断研究

利用1951－1997年全球海温、风场月平均资料和我国东部地区100个测站的冬季地面气温等资料，分析了我国东部地区冬季温度异常的时空特征和变化规律，探讨了全球海温异常与我国东部地区冬季温度异常的关系。发现赤道印度洋、赤道东太平洋、黑潮区是影响我国东部地区冬季温度异常的关键海区。前期夏、秋季赤道印度泣、赤道东太平洋海温异常与我国东部地区冬季温度异常有较好的相关关系，对预测我国东部地区冬季温度异常有一定的前兆意义。且不同关键海区的海温异常在不同季节对我国东部地区冬季温度异常产生影响的区域不同。     

THE INTERANNUAL OSCILLATION OF RAINFALL OVER CHINA AND ITS RELATION TO THE INTERANNUAL OSCILLATION OF THE AIR-SEA SYSTEM*

The quasi-biennial oscillation(QBO) and 3.5 years quasi-periodic oscillation(named TO hereafter) are exhibited in most of 48 weather stations of China by applying power spectrum analysis to the monthly rainfall data for the period from Jan. 1933 to Dec. 1987. In order to reveal the features of QBO and TO components, another rainfall data set in 160 stations over China for the period from Jan. 1951 to Dec. 1987 was analysed by means of a new method named complex empirical orthogonal function(CEOF). The results show that both QBO and TO modes exhibit two propagation ways:one originates in Northeast China, extends southward, passes through North China and reaches the eastern part of Northwest China and the northern part of Southwest China; the other appears over Guangdong and Fujian, then moves northward and westward respectively to the Huanghe-Huaihe Basin and Southwest China.These two paths of oscillation meet over North China and the area between the Changjiang River and the Huanghe River. A significant correlation exists between the interannual oscillation of the rainfall over China and that of the sea surface temperature(SST) at the equator. Although the correlation between the rainfall over China and the SST over the equatorial eastern Pacific is rather weak, the correlation between their oscillation component is pronounced.     

印度洋海温和西太平洋副高的时空分布及两者的相互影响

本文利用EOF分析方法,研究了印度洋海温和西太平洋副热带高压的时空分布特征。探讨丁两者的关系,得出印度洋海温对西太平洋副热带高压的增强和减弱有较大的影响,并对它的东西进退有一定的影响,而西太平洋副热带高压对印度洋海温的分布也有一定的影响。      

印度洋春、夏季海温对西藏高原夏季降水的影响

利用NCEP提供的1950—1997年全球月平均海表面温度场资料，首先通过EOF分解得到不同季节印度洋海温场空间分布特征，并在此基础上使用合成分析、相关分析和SVD分解等多种方法讨论了印度洋前期和同期海温异常与西藏高原夏季降水变化的关系。寻找出影响高原夏季降水的关键海区，目的为高原夏季早涝预测提供参考依据。     

北半球夏季海洋性大陆区域降水与南方涛动联系的年代际变化

利用1960—2016年夏季美国国家海洋和大气管理局(NOAA)的月平均降水资料、南方涛动指数SOI以及Niňo3指数资料、NCEP/NCAR再分析资料以及英国哈德莱中心海表温度资料,通过相关分析和回归分析,研究了北半球夏季海洋性大陆区域(Maritime Continent,MC)降水与ENSO联系的年代际变化特征。结果表明:MC地区夏季平均降水与SOI指数的相关自1998年后明显减弱。造成这种现象的原因是:南方涛动指数SOI与海温相关系数在太平洋中部为负的大值中心,且1998年之后海温异常呈中部型。这种SSTA强迫造成1998年后大气视热源异常亦偏于赤道太平洋中部,这有利于通过Gill型响应,使菲律宾以东的对流层低层存在明显的反气旋性环流,辐散增强,从而造成赤道以北降水显著减少,抵消了MC区域内南部地区降水的增加,破坏了原有的SOI为正(负)时MC地区平均降水异常增加(减少)的关系。     

ANALYSIS OF THE RELATIONSHIP BETWEEN THE CHINA ANOMALOUS CLIMATE VARIATION AND ENSO CYCLE ON THE QUASI-FOUR-YEAR SCALE

1 INTRODUCTION Much work has been done addressing the relationship between anomalous climate changes and ENSO in China and the results vary much. For instance, Li et al. (1987) [1] think that the Mei-yu (sustained rain) starts later, lasts shorter and pre…     

热带海表温度和低层风场的年际变率及与ENSO循环的相关特征研究

采用 NCEP/NCAR的 1 979～ 1 998年逐月平均的海表温度及 1 0 0 0 h Pa风场资料 ,进行滤波和均方差计算 ,得到了热带太平洋、印度洋、大西洋海表温度 (SST)和风场的年际变化特征。用旋转主分量 (RPC)方法和投影法对热带三大洋海表温度距平 (SSTA)进行分析 ,得到了各大洋 SSTA演变的主要时空特征和相应的距平风场特征 ;并用相关分析研究热带三大洋与ENSO相关的特征 ,得到三大洋间的同期相关关系为 :印度洋 SSTA与赤道东太平洋 SSTA成正相关 ,而赤道东大西洋 SSTA与赤道东太平洋 SSTA成弱的负相关 ;赤道印度洋在落后于赤道东太平洋 3个月左右时正相关达到最大 ,赤道大西洋在超前于赤道东太平洋 6个月左右时负相关达到最大 ;热带印度洋和大西洋与 ENSO相关的分量对各自大洋海表温度年际变化的方差贡献数值相近 ,最大在 40 %以上 ,平均解释方差分别为 1 4%和 1 2 %。     

江淮梅雨特征及其与北太平洋海温的SVD分析

利用江淮地区1954～2001年48年梅雨量资料,采用谐波分析、EOF、合成分析和SVD分解等方法讨论了江淮梅雨的时空变化特征以及与北太平洋海温的关系.结果表明:江淮梅雨量时空分布不均,存在显著的年际和年代际变化特征.影响江淮梅雨的海温关键区是北太平洋西风飘流区,关键影响时段是当年的1～3月;当年1～3月北太平洋西风飘流区海温异常偏高,同年江淮大部地区梅雨量异常偏多,反之亦然.SVD分解结果与合成分析的结果相吻合,通过0.05的Monte-Carlo显著性检验.     

春季格陵兰海冰与夏季中国气温和降水的关系

采有英国Hadley中心的GISST海冰面积资料，NCFP／NCAR再分析资料以及中国160站气温和降水资料，分析了春季格陵兰海冰面积与夏季中国区域气温和降水的关系。初步研究表明，春季格陵兰海冰面积变化和随后夏季我国黄河长江中下游之间地区气温以及8月份华北和西南地区降水呈明显正相关，而和6月黄河中上游地区降水则具有明显的负相关。同时，春季格陵兰海冰异常时期对应着北半球大气环流的明显主为化，表明海冰与我国气温及降水之间的联系具有一定的环流背景。