太平洋海－气热通量与长江流域降水及东亚500 hPa环流的遥相关

本文采用对两种气象要素场的相关场作ＥＯＦ分解的方法，对１９５１－１９７９年太平洋海－气感热、潜热通量与长江流域降水和东亚５００hPa环流作了分析。结果表明，太平洋海－气感热、潜热通量与后期（τ＝６）长江流域降水存在显著相关区，感热和潜热的异常分布能造成长江流域降水分布不均。同时，冬季（１２—２月）太平洋潜热通量的变化与夏季（６—８月）对流层中层的赤道辐合带、副热带高压等系统有较密切的联系。     

夏季东亚季风区500 hPa月环流异常及与我国降水关系的向量EOF分析

利用NCEP/NCAR1980～1997年夏季月平均风场及同时期我国160个测站月平均降水资料，讨论了运用向量经验正交展开(EOF)方法得到的流场月距平主要模态的时空变化特征。分析了主要模态与中国夏季降水(雨型)的相关分布，指出EOFl及EOF2模态与中国夏季降水最主要分布型式有很好的对应关系。用小波变换方法对主要模态的时间系数进行了分析，揭示了各模态的多时间尺度性质，发现3～6年周期振荡是主要的。     

大西洋-欧洲环流型和东亚槽的客观化评定

从历史资料中得到５００ｈＰａ大西洋－欧洲环境流型Ｗ，Ｃ，Ｅ３个典型场，然后利用计算实况场与３个典型场之间欧氏距离的方法，以最小欧氏距离的原则，确定逐日环流型，在指定区域中，将纬圈上最小高度值的点，经过平滑处理后的平均经度值和高度值，确定东亚槽的位置和强度，这一工作将使环流物理量的评定更客观化及自动化。     

由卫星辐射测量资料计算候、旬和月平均海面温度场

本文介绍了一个从NOAA卫星AVHRR红外窗区通道辐射测量资料获取候、旬和月平均海面温度场的计算机软件系统,并提供了用1987年6月的NOAA-9卫星AVHRR资料,对软件系统进行测试得到的旬和月平均海面温度场。     

Recurrent climate winter regimes in reconstructed and modelled 500 hPa geopotential height fields over the North Atlantic/European sector 1659–1990

Recurrent climate winter regimes are examined from statistically reconstructed and modelled 500 hPa geopotential height fields over the North Atlantic/European sector for the period 1659–1990. We investigate the probability density function of the state space spanned by the first two empirical orthogonal functions of combined winter data. Regimes are detected as patterns that correspond to areas of the state space with an unexpected high recurrence probability using a Monte Carlo approach. The reconstruction and the model reveal four recurrent climate regimes. They correspond to the two phases of the North Atlantic Oscillation and two opposite blocking patterns. Complemented by the investigation of the temporal evolution of the climate regimes this leads to the conclusion that the reconstructed and the modelled data for this geographic sector reproduce low-frequency atmospheric variability in the form of regime-like behaviour. The overall evidence for recurrent climate regimes is higher for the model than for the reconstruction. However, comparisons with independent data sources for the period 1659–1990 revealed a more realistic temporal evolution of the regimes for the reconstructed data. Electronic Supplementary Material Supplementary material is available for this article at     

The Relationship between the Meridional Profile of Zonal mean Geostrophic Wind and Station Wave at 500 hPa

The sea-level pressure (SLP), 500 hPa height, zonal-mean 500 hPa height ([Z500]), stationary wave ed dy component of the 500 hPa height (Z*500) and zonal-mean 500 hPa geostrophic wind [Ug ] fields poleward of 20°N are examined for the period 1958-1997, with emphasis on the winter season. The relationships be tween the Arctic Oscillation (AO)index and algebraic difference of the zonal-mean wind in 55°N and 35°N (Ut) index were investigated, making use the Monte Carlo procedure, Singular Value Decomposition (SVD), Empirical orthogonal function (EOF) and regression method. The leading modes of empirical orthogonal function (EOF＇s) of SLP are more robust than the 500 hPa height EOF＇s, not only in the ratio of the two largest eigenvalues, but in more zonally symmetric. Comparing the meridional profiles of zonal-mean wind amplitude associated with the AO and Ut index, the profiles for the two indexes are very similar, both with respect to amplitude and the placement of the maximum and minimum. Comparing the station wave component of 500 hPa height field regressed upon the AO and Ut index, there is one-to-one correspondence between all the major centers of action in the two maps, especially in the North Atlantic and Eurasian continent. The pattern is unlike the prominent teleconnection patterns, they have hemispheric ex tent and cannot be interpreted in term of the individual wavetrains.     

500 hPa场的纬向平均地转风的经向廓线分布与稳定波型的联系

应用蒙特卡罗方法、奇异值分解（SVD）、自然正交分解（EOF）和回归分析等统计方法，探讨冬季北半球海平面气压场与 500 hPa高度场、500 hPa纬向平均场和纬偏场（Z5ua）中稳定波的联系。依据正交分解分析，海平面气压场的第一与第二特征向量权重之比远大于 500 hPa，其比值达2倍，而且它的第一特征场更具有纬向对称性。在应用蒙特卡罗方法讨论上述两场的第一与第二特征向量时间序列的差异时，海平面气压场第一特征向量是十分稳定的，不因随机抽样而改变，一再重复出现；因此认为海平面气压场的第一特征向量场比 500 hPa高度场具有更好的重复性和代表性。在比较海平面气压场第一特征向量时间序列（即北冰洋涛动指数）与 500 hPa场上 35°N－55°N纬向风差值（即 Ut指数）时，两者的相关达 0．85；在它们与 500hPa纬向平均风场的回归廓线图中。无论在振幅和极大极小值的位置上，都十分相似。在比较上述两指数与纬偏场（Z500）的回归场时，所有的正负大值中心，位置全部一一对应，中心值也相近，尤其在北大西洋和欧亚大陆。在 500 hPa纬向平均风场和纬偏场（Z500）的奇异值分解分析中，其结果正与上述两回归场相仿；应用正交分解分析Z500场，其第二特征向量场与上述的回归场也完全一致。因此认为这种覆盖整     

Analysis of mean temperature variations at the 1000/500 hPa layer over Europe, 1945–88

Summary Mean temperature (T) values at the 1000/500 hPa atmospheric layer over Europe have been calculated on the basis of grid point data, for the period between 1945–88. An analysis of trend inT values over the whole period found that most of the area is characterized by positive trends. During the summer of the last sub-period, 1970–88, there was a positive trend predominant over most of the region, with a maximum rate of 0.5°C/10 years. It is therefore evident that the warmth of the 1980s is not just a surface phenomenon over the region. Regarding significant periodicities, the well known Quasi Biennial Oscillation (QBO) was identified only for some grid points of the NW and NE regions, while the Southern Hemisphere Oscillation (SO) was only identified for the Mediterranean area.With 8 Figures     

基于前期观测降水和500 hPa高度场的西北太平洋热带风暴生成频数的新预测方案

利用前期1—2月和4—5月平均的东半球格点降水与500 hPa高度场资料,通过多元线性逐步回归,建立了预测西北太平洋年热带风暴生成频数的预测方案。由于分别使用了欧洲中期数值预报中心和美国国家环境预测中心的大气再分析资料,建立了两个预测模型,对1979—2002年的预测交叉检验的距平相关系数分别为0.78和0.74。预测的多年平均绝对误差是3.0和3.2,即多年平均西北太平洋年热带风暴生成频数的10%左右。进一步指出：实际预测中可以把两个模型的预测结果平均作为最后预测结果,这样的话,多年交叉检验的距平相关系数是0.88,多年平均的预测绝对误差是1.92个。这样就可能得到更加准确的预测。本文结果还只是该方案的交叉检验结果,尚需在实际预测中进一步检验其能力。     

A Multi-Statistical analysis of the southern oscillation (SO) and its relation to the mean monthly atmospheric circulation at 500 hPa in the northern hemisphere

In this paper the correlation analysis, factor analysis, fuzzy classification, and principal component analysis (PCA) are performed for the southern oscillation index (SOI) from the Climate Analysis Center (CAC) at the NOAA. It is shown that the 12-month SOI can be classified into two groups: one from January through April and the other from May through December. They differ in persistency and correlation. It is also found that the year of strong or weak SO can be defined by the first principal component of the SOI. The 11 years of weak SO thus defined contain 9 El Nino events.In addition, the relations between the SOI and 500 hPa geopotential height, mean monthly zonal height, mean monthly interzonal height differences, centers of atmospheric activities, characteristics of the atmospheric circulation (the intensity index of the north polar vortex, the area index of the subtropical West Pacific high, mean monthly zonal and meridional circulation indexes in Asia and Eurasia) in the period of 24 months from January through December of the next year have been examined on the basis of the monthly data from 1951 through 1984. The correlation coefficients and Mahalanobis distances are thus presented. Analysis indicates that in the early part of the low SOI year, i.e., in April, the 500 hPa geopotential height north of 75oN is significantly low and then becomes higher in May. It is found that in April the trough of the first harmonic wave is in the Eastern Hemisphere and the contribution of its variance is smaller than in May. Analysis shows that the opposite is true in the high SOI year. Such variation in the height field during the April-May period is an early signal of the SO at higher latitudes.In the end, a statistical prediction model for the SOI is presented, by means of which a low SOI year as well as an El Nino event has been successfully predicted for 1986.     

春季南亚高压在中南半岛上空建立与500hPa副高断裂的关系

利用NCEP／NCAR再分析资料及NOAA的OLR资料,研究了春季南亚高压在中南半岛上空建立与500hPa副高在孟加拉湾上空断裂的关系。结果表明,南亚高压建立之前,对流从“海洋大陆”向北推进,首先在中南半岛建立;而孟加拉湾地区由于青藏高原感热作用在对流层中低层形成一个反Hadley环流型的局地经圈环流,15°N附近500—700hPa有下沉运动中心,它抑制了孟加拉湾对流的建立,也不利于500hPa副高带断裂。南亚高压在中南半岛建立之后,位于高压中心西南侧的孟加拉湾上空出现一个强的辐散中心,孟加拉湾地区15°N附近的下沉运动消失,对流发展起来,降水量增加并释放大量潜热,非绝热加热中心位于500hPa,此时副高脊线断裂。因此,高层南亚高压建立所产生的辐散运动很可能对孟加拉湾上空500hPa副高带断裂及对流建立起到了触发作用。     

冬季亚欧500hPa高度与下表面温度异常的大尺度相关型

使用NCEP／NCAR再分析资料，分析了冬季欧亚地区500hPa高度距平场与下表面温度距平场间的大尺度相关空间型，结果表明，两个场整体相关程度远高于随机水平，得到4对显著的耦合空间型，解释两场间协方差平方和的86％和各自方差的58％和38％，反映500hPa环流两种不同纬带的纬向环流异常和两种不同形态的经向环流异常，两个场距平之间的配合是受静力平衡关系支配的，秋季的表面温度异常能给出中低续500hPa高度距平符号的信息。     

秋、冬季500hPa月平均极涡变化与黑龙江省夏季温度的关系

利用经验正交函数（ＥＯＦ） 展开方法,研究了黑龙江省夏季温度时空分布的主要特征,找出北半球５００ ｈＰａ月平均图上秋、冬季（１０ ～１１ 月） 极涡位置和强度变化与次年黑龙江省夏季温度主要特征的关系,并用于制作夏季温度预报     

Recent variations in 700 hPa geopotential heights in summer over Europe and the Middle East,and their influence on other Meteorological factors

Summary Recent variations in atmospheric circulation in the eastern Mediterranean are analyzed and discussed. Interdecadal differences in mean monthly 700 hPa geopotential heights for June, July, and August in the period 1951–1980 show a trend of decreasing pressure of the subtropical high pressure belt over the Sahara Desert. The decrease is observed in the magnitude of the high pressure, in its areal extent, and in its northward position. Broader variations in other meteorological variables, such as rainfall regimes, temperature fields, wind variability, and evapotranspiration rates, are discussed in relation to variations in pressure fields and in indices of circulation such as the North Atlantic Oscillation. The trend from the 1950s through the 1970s was towards more temperate summer climate in the region.With 5 Figures     

有关南半球大气环流与东亚气候的关系研究的若干新进展

南半球大气环流是全球大气环流的重要组成部分,也是影响气候变化和亚洲季风系统的一个重要因素.中国气象学家很早就注意到南半球大气环流对东亚夏季风降水的影响.近年来,有关南半球气候变率的研究目前正受到世界气象学家越来越多的关注.南半球中高纬大气资料的丰富及南极涛动的确定,使得认识南半球高中纬环流的年际变动规律及其与东亚气候关系成为可能.本文主要介绍近年来有关南极涛动的年际变化与沙尘天气发生频次及东亚冬春季气候的关系,古气候资料揭示的南极涛动与华北降水的关系,以及南半球大气环流与长江中下游夏季降水的关系和南极涛动变率的可预测性等方面的研究进展.并对未来研究方向作了初步的展望.     

青藏高原春季500 hPa纬向风季节内振荡特征及其与我国南方降水的关系

利用NCEP/NCAR日平均再分析资料及中国753个测站日降水资料,采用带通滤波、小波功率谱、合成分析等方法研究了青藏高原春季500 hPa纬向风季节内振荡特征及其与我国南方降水的关系.结果表明,青藏高原春季500 hPa纬向风存在明显的10~30 d季节内振荡特征,该低频振荡主要表现为自西向东和自北向南的传播特征.通过位相合成分析发现,这种季节内振荡对我国南方春季降水有重要影响.当高原500 hPa纬向风季节内振荡处于2~3位相时(即高原上盛行西风异常),对应于我国南方地区春季降水明显偏多;反之,当季节内振荡处于相反位相时(6~7位相,即高原上盛行东风异常),对应于我国南方春季降水明显偏少.南方春季最大正(负)异常降水的出现滞后于高原季节内振荡的峰值(谷值)位相,其滞后时间为2 d.分析结果还表明,高原上空纬向风的季节内振荡活动主要通过中纬度大尺度环流异常对我国南方春季降水产生影响.     

中国东部夏季雨带类型与前期北半球500 hPa环流异常的关系

根据1951～1986年的资料,在文献[1]对中国东部夏季（6～8月）雨带分布类型的基础上,分析了各雨型与前期北半球500 hPa环流异常的关系。重点研究了各雨型的长期天气过程。发现不同雨型前期环流有不同的长期演变过程。指出中高纬和低纬环流不同季节变异及其相互作用,可能是导致中国东部各种雨带分布类型的一个重要因素。并提出了一些预报线索,可供夏季我国大范围旱涝趋势的长期预报参考。     

Signal analysis of the atmospheric mean 500/1000 hPa temperature north of 55°N between 1949 and 1994

 The lower tropospheric mean temperature 500/1000 hPa is examined in the Northern Hemisphere high-latitude region north of 55°N with regard to a climate change signal due to anthropogenic climate forcing as a supplement to previous studies which concentrated on near surface temperatures. An observational data set of the German Weather Service is compared with several model simulations including different scenarios of greenhouse gas and sulfate aerosol forcing derived from the two recent versions of the coupled climate model in Hamburg, ECHAM-3/LSG and ECHAM-4/OPYC. The signal analysis is based on the optimal fingerprint method, which supplies a detection variable with optimal signal-to-noise ratio. The natural variability measures are derived from the corresponding long-term control experiments. From 1970 onward, we find high trend pattern analogies between the observational data and the greenhouse-gas induced model simulations. The fingerprint of this common temperature signal consists of a predominate warming with maximum over Siberia and a weak cooling over the North Atlantic reaching an estimated significance level of about 1%. A non-optimized approach has also been examined, leading to even closer trend pattern correlations. The additional forcing by sulfate aerosols decreases the correlation of this climate change simulation with the observations. The natural variability constitutes about 50% of the conforming trend patterns. The signal-to-noise ratio is best over the oceans while the tropospheric temperatures over the land masses are contaminated by strong noise. The trend pattern correlations look the same for both model versions and several ensemble members with different noise realizations. Received: 4 January 1999 / Accepted: 11 April 2001