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1.
VARIATIONS IN THE TELECONNECTION INTENSITY INDICES AND THEIR REMOTE RESPONSE TO THE EL NINO EVENTS IN THE NORTHERN HEMISPHERE 
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下载免费PDF全文 In this study,the monthly and seasonal teleconnection intensity indices of the Pacific/North American(PNA),Western Atlantic(WA),Western Pacific(WP),Eastern Atlantic(EA)and Eurasian(EU)patterns for the periodfrom 1951 through 1990 are calculated.On this basis,their climatic variations and the relationship between the fiveteleconnection intensity indices and the El Nino events are examined.It is noted that when El Nino is at its mature stage(winter),the weak WP pattern is mainly characteristic of the circulation and the strong PNA pattern is the next.Insummer when El Nino occurs and develops,the strong EU,weak WP and weak WA patterns are the main characteris-tics without the PNA circulation anomalies.Finally,by the nonlinear mapping method a nonlinear mapping diagram isestablished for diagnosing El Nino using three summer teleeonuection intensity indices and May and August SouthernOscillation Indices(SOIs).Thus,the El Nino phenomenon occurring in 1991 is diagnosed.Besides,the winter atmos-pheric circulation of the 1991/1992 El Nino is found to be the weak WP pattern and the PNA pattern is also weak. 相似文献
2.
北半球冬半年遥相关型强度指数的年际变化特征及其与厄尔尼诺的遥响应 总被引：1，自引：0，他引：1
计算了1951—1990年冬半年逐月以及冬季的PNA、WA、WP、EA、EU型的遥相关强度指数。在此基础上,研究了它们的气候变化特征以及这5个遥相关型强度指数与厄尔尼诺的关系。指出,厄尔尼诺发展的盛期(冬季),以北半球西太平洋型(WP)明显偏弱为主要特征,其次才是太平洋北美型(PNA)偏强。1991年发生的一次厄尔尼诺,在盛期是弱PNA型,弱WP型。此外,还研究了遥相关强度指数用于天气预报的问题。 相似文献
3.
北半球冬季大气环流遥相关的长期变化及其与我国气候变化的关系 总被引：86，自引：2，他引：86
研究北半球冬季大气环流遥相关型的长期变化发现：ＷＡ，ＰＮＡ型有明显趋势变化及年代际变化。ＷＡ型有明显负趋势，ＰＮＡ型有正趋势，它们的强度突变分别发生于１９８０年代初（ＷＡ型１９８３年由强转弱）及１９７０年代中（ＰＮＡ型１９７６年由弱转强）。与此同时，亚洲地区、亚欧地区的经向环流强度于１９８３年突然减弱。大气环流及遥相关型强度的这种年代际变化是中国冬季气候变化的一个重要原因。 相似文献
4.
Studies on the northern early summer teleconnection patterns,their interannual variations and relation to drought/flood in China 总被引：2，自引：0，他引：2
By using the one-point correlation method, calculations have been made of the northern early summer 500 hPa teleconnection patterns. Seven teleconnection patterns are revealed, namely, the Western Atlantic (WA), the Eastern Atlantic (EA), the Eurasian (EU), the Bengal / Northern Pacific (BNP), the Western Pacific (WP), the East Asian / Pacific (EAP), and the Huanghe / East Asian (HEA) patterns. Their centers are determined and their yearly intensity indices (1951-1990) are calculated. On this basis the relationship between their interannual variations and the drought / flood in China is examined. It is noted that the EU, HEA and EAP wave trains are closely related to the drought/ flood in China. The HEA and EAP patterns strongly influence the precipitation in eastern China. For ex-ample, the fierce floods experienced in 1991 early summer over China are related to the weak EAP and strong HEA patterns. 相似文献
5.
冬季500hPa候平均高度场的遥相关 总被引：1，自引：0，他引：1
早在本世纪初,人们就已发现大气环流存在遥相关现象。Wallace等从北半球冬季500hPa月平均高度场总结出5种遥相关型。理论研究和数值模拟表明遥相关型是正压不稳定及Rossby波在球面上频散的反映。由于Rossby波频散是定性估计大型环流中期变化趋势的基本思路及500hPa候平均图是中期预报的基本工具,因此,分析500kPa候平均高度场的遥相关是有意义的。 相似文献
6.
20世纪70年代末前后北半球冬季对流层遥相关的时空演变研究 总被引：2，自引：1，他引：1
应用NOAA提供的1950～2008年月平均500 hPa高度场再分析资料、海表温度、太平洋年代际振荡(PDO)指数和大西洋三极模(ATM)指数, 研究了20世纪70年代末前后北半球冬季对流层遥相关的时空演变规律。相关分析、Mann-Kendall分析和凝聚小波分析的结果表明, 20世纪70年代末以来, 太平洋—北美(PNA)型、欧亚(EUP)型、西太平洋(WP)型和西大西洋(WA)型四种遥相关空间分布和时间演变产生较为显著的变化。空间分布的变化既体现在遥相关正、负异常中心的强度上, 也体现在正、负异常的范围上; 时间演变方面的变化则体现在PNA和WP遥相关指数具有上升趋势, EUP和WA遥相关指数具有一定下降趋势。20世纪70年代末以来, 影响北半球冬季5种遥相关型的海温关键区均有所改变。其中, 各大洋上影响EUP遥相关型的海温关键区面积显著缩小, 影响WA遥相关型的太平洋海温关键区面积显著缩小, 影响EA遥相关型海温关键区在北大西洋中南部改变明显; 在16年以上时间尺度上, PDO变化是造成北半球冬季PNA、 EUP、 WP三种遥相关型变化的主要原因; ATM变化是造成北半球冬季WA和EA两种遥相关型变化的主要原因。 相似文献
7.
Seasonality of the Interaction between Convection over the Western Pacific and General Circulation in the Northern Hemisphere 总被引：2，自引：0，他引：2
The seasonality of the interaction between convection over the western Pacific and general circulation in the Northern Hemisphere (NH) is analyzed in the present paper with singular value decomposition (SVD) and empirical orthogonal function (EOF) analysis approaches, based on 500 hPa monthly mean geopotential height data and high-cloud amount data. The analyses demonstrate that coupled dominant patterns in the interaction between the convection over the western Pacific and the general circulation in NH are different in various seasons. In spring, the convection over the western Pacific is closely related with the western Atlantic (WA) and North Pacific (NP) like patterns of the general circulation in NH, and some associations between the WA and NP like pat?terns and the El Ni?o / Southern Oscillation (ENSO) cycle are also existed. The Pacific Japan (PJ) pattern is the dom?inant pattern in the interaction between the interannual variabilities of the convection over the western Pacific and the general circulation in NH summer. The WA like pattern and 3-4 year period oscillation are also relatively obvious for the summer case. In autumn, the convection over the western Pacific is closely linked with the Eurasian (EU) like pattern and the Atlantic oscillation in the general circulation in NH, it is suggested that in autumn the vitiation of convective activity over the western Pacific is largely affected by the general circulation anomaly (cold air from high latitudes) through EU like teleconnection pattern. Abrupt change happened by the end of 1980’s in the autumn interaction. The strong interaction between the western Pacific (WP) and EU like patterns in the general circulation in NH and the convection over the western Pacific and a linear trend of increasing of this interaction are also suggested in winter. It is also demonstrated that the interaction in summer and winter is stronger than in the transition seasons (spring and autumn). 相似文献
8.
西太平洋副热带高压异常进退的对比分析 总被引：4，自引：4，他引：0
对1980年7月29日—8月16日西太平洋副高位置持续偏南和1983年7月16日—8月12日西太平洋副高位置持续偏北的两次季节内副高中期进退过程的环流特征和加热差异作了对比分析,讨论了东亚季风与对流活动、副高进退之间的关系. 相似文献
9.
北半球冬季大气环流遥相关型特征与我国区域气候 总被引：7，自引：2，他引：7
计算了1951／1952～2002／2003年北半球冬季大气环流遥相关型的强度指数，研究了它们的长期变化和近期特征，指出近10年来WA型的负趋势，PNA型的正趋势还在持续并有所加强。它们的强度突变分别发生于20世纪80年代初(WA型1984年由强转弱)及70年代中(PNA型1976年由弱转强)。还指出，近10年来，亚洲(亚欧)地区的纬向环流强度继续在加强，经向环流强度继续在减弱，大气环流及遥相关型强度的这种变化是中国冬季气候变化的一个重要原因。 相似文献
10.
基于1901-2000年多种海-气资料,分析了厄尔尼诺成熟年冬季-初夏西北太平洋异常反气旋（WNPAC）的年际变化特征及其对东亚气候的影响。结果表明,无论是厄尔尼诺事件成熟期的冬季还是次年的春季和初夏,WNPAC的年际变化主要存在两个空间变化型,即反映其强度变化的经验正交函数分解第1模态和反映其位置变化的第2模态。厄尔尼诺成熟年冬季WNPAC强度不仅与赤道中东太平洋海温异常有关,而且与太平洋西部（WP）型遥相关的强度有关,而其位置的变化则主要与西北太平洋局地海温异常以及北极涛动（AO）有关;次年春季,WNPAC的强度除了与赤道中东太平洋海温异常和太平洋西部型遥相关存在显著相关外,还与赤道大西洋海温异常有关,而其位置的变化则主要与西北太平洋局地海温异常和太平洋西部型遥相关有关;次年初夏,WNPAC强度主要与西北印度洋和西南印度洋的海温异常以及东亚-太平洋（EAP）型遥相关的强度有关。进一步分析表明,成熟年冬季-初夏WNPAC的强度和位置的变化均可对东亚地区降水异常分布产生影响,这对预测厄尔尼诺事件发生后冬季及后期春、夏季节东亚地区降水异常分布具有一定的指示意义。此外,次年初夏,WNPAC强度变化与西北太平洋台风发生频数存在显著负相关,即WNPAC越强,台风发生的频数越少,反之亦然。 相似文献
11.
冬季中高纬500hPa高度和海表温度异常特征及其相关分析 总被引：6，自引：4，他引：6
用旋转主分量（ＲＰＣ）方法，分析１９４８年到１９８８年４０个冬季的中高纬５００ｈＰａ高度场以及全球海表温度异常（ＳＳＴＡ）场的最主要的时空分布特征。然后通过交叉相关来讨论海气的同期相关特征。结果显示，冬季中高纬５００ｈＰａ高度场最明显的异常型分别是太平洋北美型（ＰＮＡ），西太平洋型（ＷＰ），西大西洋型（ＷＡ）以及东大西洋欧亚型（ＥＡＥＵ）。冬季ＳＳＴＡ最明显的区域是赤道东太平洋（ＥＥＰ）和赤道大西洋（ＥＡＬ）。其次是中纬度东北太平洋（ＮＥＰ）及两大洋西部（ＮＷＰ和ＮＷＡ）。中高纬度海气之间有很好的相关。与中高纬度５００ｈＰａ高度场ＰＮＡ型明显相关的是中高纬度东北太平洋（ＮＥＰ）和赤道东太平洋（ＥＥＰ）的ＳＳＴＡ。前者的强相关中心在中高纬；后者的强相关中心在中低纬。而与ＷＡ型明显相关的是中高纬度北大西洋的ＳＳＴＡ。中高纬度海气之间最强的相关在海气异常对应的空间位置上。而且这种区域性或邻域性的海气相关呈正相关，暖ＳＳＴＡ对应于正高度异常，冷ＳＳＴＡ对应于负高度异常 相似文献
12.
利用欧洲中期天气预报中心ECMWF(European Center for Medium-range Weather Forecast)逐日再分析资料(ERA40),通过经验正交函数(empirical orthogonal function,EOF)分解发现,冬季北太平洋东部风暴轴有着显著的年际变化特征:第一变化模态为在气候平均位置南北相反的偶极子变化型,第二变化模态为在气候平均位置处一致增强或减弱的变化型,第三变化模态为三极子的变化型。进一步的回归分析发现:当东部风暴轴南压(北抬)时,同期冬季是一种厄尔尼诺(拉尼娜)年海温异常空间分布型,中纬度北太平洋海区以及赤道中、东海区,冬季冷(暖)异常的洋面上是异常低压(高压),对流层中层是太平洋—北美型(Pacific-North American Pattern,PNA)遥相关的正(负)位相;当东部风暴轴增强(减弱)时,同期冬季黑潮区海温偏暖(偏冷),对流层中层表现为西太平洋型(West Pacific Pattern,WP)遥相关的正(负)位相;当东部风暴轴呈现西北—东南+-+(-+-)相间三极子的分布时,同期冬季巴布亚新几内亚附近海温异常偏暖(冷),夏威夷附近海温异常偏冷(暖),冬季冷(暖)异常的洋面上是异常低(高)压,对流层中层表现出类似PNA正(负)位相。EOF分解各模态所对应时间系数与阿留申低压(Aleutian Low,AL)指数、PNA指数、Nino3指数、WP指数、黑潮海温(Kuroshio Current,KC)指数之间存在显著的相关,这些证明了东部风暴轴与同期大气环流及SST异常之间的联系。 相似文献
13.
Diagnostic studies have been done of the seasonal and interdecadal variations of the coupling patterns for the air-sea interactions in the northern Pacific region, by using 500-hPa geopotential height field of the Northern Hemisphere and monthly mean SST field of northern Pacific Ocean (1951 ～ 1995) and with the aid of the Singular Value Decomposition (SVD) technique. The results show that: (1) The distribution patterns of SVD, which link with the El Nifo (or La Nina) events, are important in the interaction between the atmosphere and ocean while the atmosphere, coupling with it, varies like the PNA teleconnection does. The coupling of airsea interactions is the highest in the winter (January), specifically linking the El Nino event with the PNA pattern in the geopotential height field. Of the four seasons, summer has the poorest coupling when the 500-hPa geopotential height field corresponding to the La Nina event displays patterns similar to the East Asian-Pacific one (PJ). The spring and autumn are both transitional and the coupling is less tight in the autumn than in the spring. (2) Significant changes have taken place around 1976 in the pattern of air-sea coupling, with the year's winter having intensified PNA pattern of 500-hPa winter geopotential height field, deepened Aleutian low that moves southeast and the summer following it having outstanding PJ pattern of 500-hPa geopotential height field.which is not so before 1976. 相似文献
14.
The impacts of four teleconnection patterns on atmospheric circulation components over Eurasia and the Pacific region, from low to high latitudes in the Northern Hemisphere (NH), were investigated comprehensively in this study. The patterns, as identified by the Climate Prediction Center (USA), were the East Atlantic (EA), East Atlantic/Western Russia (EAWR), Polar/Eurasia (POLEUR), and Scandinavian (SCAND) teleconnections. Results indicate that the EA pattern is closely related to the intensity of the subtropical high over different sectors of the NH in all seasons, especially boreal winter. The wave train associated with this pattern serves as an atmospheric bridge that transfers Atlantic influence into the low-latitude region of the Pacific. In addition, the amplitudes of the EAWR, SCAND, and POLEUR patterns were found to have considerable control on the “Vangengeim–Girs” circulation that forms over the Atlantic–Eurasian region in winter or spring. The EA and EAWR mainly affect the westerlies in winter and spring and the POLEUR and SCAND, respectively, in summer and winter. Strong westerlies confine the extension of the North Polar vortex, which generally results in a small weak vortex and a shallow East Asian trough located in a position further east than normal. Furthermore, the North Polar vortex presents significant connections with the patterns during winter and summer. Analyses in this work suggest that the teleconnection patterns in summer could be driven, at least partly, by the Atlantic Multidecadal Oscillation, which to some degree might transmit the influence of the Atlantic Ocean to Eurasia and the Pacific region. 相似文献
15.
The NCEP–NCAR reanalysis dataset and the Had ISST dataset(1959–2014) are used to analyze the impact of two types of El Nio events, i.e., eastern Pacific El Nio(EP-El Nio) and central Pacific El Nio(CP-El Nio) events, on the duration of major and minor sudden stratospheric warmings(SSWs) in Northern Hemisphere winter(November to February). Although the frequency of major and minor SSWs during different types of El Nio shows no distinct differences, the duration of both major and minor SSWs during CP-El Nio is shorter than that during EP-El Nio. The spatial distribution of geopotential height anomalies preceding major SSWs resembles the western Pacific(WP) teleconnection pattern, while the spatial distribution of geopotential height anomalies preceding minor SSWs bears similarity to the Pacific–North America(PNA)teleconnection pattern. An enhancement of the strength of both wavenumber 1 and wavenumber 2 is found before major SSWs. Before minor SSWs, wavenumber 1 is also strengthened, but wavenumber 2 is weakened. The analysis also reveals that EP-El Nio tends to induce positive phases of PNA and WP teleconnections, while CP-El Nio induces negative-phase WP teleconnection. As the positive phases of the PNA and WP teleconnections are related to the strengthening of wavenumber 1, EP-El Nio causes an enhancement of wavenumber 1 in the high-latitude upper troposphere and an enhancement of the upward wave flux in the high-latitude stratosphere, accompanied by a negative anomaly in Eliassen–Palm flux divergence in the subpolar stratosphere, which accounts for the longer SSW duration during EP-El Nio than during CP-El Nio. 相似文献
16.
塞罕坝地区是我国生态文明建设的典范区,本文对塞罕坝地区多年气温和降水的大尺度环流异常进行合成分析,研究其环流特征及关键环流因子。结果表明：1962-2020年塞罕坝地区气温总体呈偏高趋势,春、秋、冬季降水呈偏多趋势,夏季降水呈偏少趋势。大尺度环流背景下,各季节影响塞罕坝地区气温和降水的主要因子不同,通过挑选最优因子分析得出：塞罕坝地区受大气环流指数影响明显,春季太平洋-北美遥相关型指数（PNA）、夏季北大西洋涛动指数（NAO）、秋季西太平洋遥相关型指数（WP）、冬季高原季风指数（PMI）与该地气温和降水有较好的关系。 相似文献
17.
冬、夏季青藏高原地面加热场激发的500hPa遥相关型 总被引：3，自引：0，他引：3
本文用青藏高原地面加热场强度来表征高原的加热状况，并用统计的方法，分析了冬季（２月）和夏季（７月）青藏高原地面加热场强度与同期５００ｈＰａ位势高度的遥相关关系，得到如下结论：冬季高原地面加热场可激发北半球５００ｈＰａ产生遥相关型，这种遥相关型可看成是二维Ｒｏｓｓｂｙ波列由低纬向东北方向传播；夏季高原地面加热场可激发北半球５００ｈＰａ产生类似于ＥＵ型的遥相关，这种遥相关型可看成二维Ｒｏｓｓｂｙ波列由 相似文献
18.
Based on the monthly mean OLR, geopotential height and wind data from the NCEP/NCAR reanalyzed data sets for 1982-1996, the atmospheric teleconnection associated with the warm pool of the tropical western Pacific and Asian monsoon region during E1 Nino and non-El Niño years are studied diagnostically in this paper. It is found that, the teleconnection pattern caused by the activity of the Asian summer monsoon (ASM) emanates from the Asian monsoon region to the tropical eastern Pacific via the Aleutians in summer of the El Niño years. In the non-El Niño years, however, the ASM-related teleconnection pattern stretches northward and westward from the Asian monsoon region, exerting its influences mainly on the circulation over middle and high latitude rather than that over the tropical eastern Pacific. Evidences also show that the anomalous convection over the tropical western Pacific warm pool leads to the East Asia/Pacific(EAP) teleconnection pattern during the non-El Niño years. It is interesting to note that the teleconnection in the 500 height field associated with the warm pool convection disappears in the El Niño years. The differences of the teleconnection pattern between the El Niño years and the non-El Niño years suggest that the activities of the ASM and the convection over the warm pool of the tropical western Pacific, the most energetic weather events in boreal summer, are intertwined and interactive with other global-scale circulation in different ways under different climate backgrounds. 相似文献
19.
20.
Influence of North Atlantic sea surface temperature (SST) anomalies on tropical Pacific SST anomalies is examined. Both summer and winter North Atlantic SST anomalies are negatively related to central-eastern tropical Pacific SST anomalies in the subsequent months varying from 5 to 13?months. In particular, when the North Atlantic is colder than normal in the summer, an El Ni?o event is likely to be initiated in the subsequent spring in the tropical Pacific. Associated with summer cold North Atlantic SST anomalies is an anomalous cyclonic circulation at low-level over the North Atlantic from subsequent October to April. Corresponded to this local response, an SST-induced heating over the North Atlantic produces a teleconnected pattern, similar to the East Atlantic/West Russia teleconnection. The pattern features two anticyclonic circulations near England and Lake Baikal, and two cyclonic circulations over the North Atlantic and near the Caspian Sea. The anticyclonic circulation near Lake Baikal enhances the continent northerlies, and strengthens the East-Asian winter monsoon. These are also associated with an off-equatorial cyclonic circulation in the western Pacific during the subsequent winter and spring, which produces equatorial westerly wind anomalies in the western Pacific. The equatorial westerly wind anomalies in the winter and spring can help initiate a Pacific El Ni?o event following a cold North Atlantic in the summer. 相似文献