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1.
By prescribing sea surface temperature anomalies(SSTAs)over eastern equatorial Pacific inJanuary—March,the lag influence of ENSO(El Nino and La Nina)on monsoon over East Asiahas been studied.The results suggest that,due to the excitation of atmospheric low-frequencyoscillation by the SSTA,ENSO has significant lag influence on the monsoon over East Asia.During the summer after E1 Nino,the subtropical high over western Pacific is intensified andshows the northward and westward displacement,meanwhile,the rainfall over East China isbelow normal,especially in North China:during the winter after E1 Nino,both the Asian troughand the winter monsoon over East Asia are strengthened.During the summer after La Nina,theanomalous subtropical high prevails over the lower reaches of Yangtze(Changjiang)River,therainfall between Yangtze and Huaihe Rivers is below normal:during the winter after La Nina,both the Asian trough and the winter monsoon over East Asia are weaker.Compared with LaNina,the effect of El Nino is stronger,but it is not always opposite to the one of La Nina. 相似文献
2.
东亚和西北太平洋地区气候的准10年尺度振荡及其可能机制 总被引：14，自引：1，他引：13
本文基于对气候、大气环流和海表水温的资料分析以及简单的理想化海气耦合模式的分析,研究了东亚和西北太平洋地区气候的准１０年振荡及其可能机制。研究表明,东亚和西北太平洋地区的气候（降水和地面气温等）和大气环流（环流指数和副高活动等）的演变都有明显的准１０年振荡;同赤道太平洋ＳＳＴＡ主要为ＥＮＳＯ循环不同,西北太平洋ＳＳＴＡ主要表现为准１０年尺度的振荡,且同气候和大气环流的准１０年变化密切相关;中纬度海－气相互作用可产生一种甚低频耦合波（１０年左右周期）,它可能是海气系统准１０年振荡的重要机制之一 相似文献
3.
东亚冬季风对秋、冬季SSTA响应的数值试验 总被引：3，自引：1，他引：3
利用NCAR CCM2模式，通过设计多组数值试验方案，研究了东亚冬季风对赤道中东太平洋、中纬度太平洋秋、冬季SSTA的响应。模拟结果表明，东亚冬季风对秋、冬季太平洋SSTA均存在一定的响应，但冬季风对SSTA的响应存在显著的季节和海域差异，并表现出不同的异常响应形态。东亚冬季风对秋季SSTA的显著响应区域位于中纬度太平洋地区，该区域的SST的持续异常，可以引起欧亚、北美地区冬季大气环流的异常，并伴随有明显的EU型和PNA型波列特征，秋季中纬度太平洋SST持续异常偏冷（暖），能够引起有利于强（弱）东亚冬季风的环流异常。而冬季风对冬季SSTA的响应则为赤道中东太平洋和中纬度太平洋SSTA共同作用的结果，在两个区域SSTA的同时强迫下，大气环流表现出类似PNA及WP型波列分布的异常响应特征，赤道中东太平洋的正（负）的SSTA及中纬度太平洋负（正）的SSTA，将导致弱（强）冬季风的发生。 相似文献
4.
利用MPI-ESM-LR模式RCP8.5情景下海冰浓度、降水、海表面温度、500 hPa位势高度和850 hPa风场等数据,对比分析了一次北极海冰突变前后春季海冰与东亚夏季降水关系的差异,并探究其可能成因。结果表明:1)北极海冰突变导致北极海冰浓度(Sea Ice Concentration,SIC)和ENSO对东亚夏季降水的影响均发生变化。突变前SIC和ENSO共同影响降水年际变化;突变后ENSO主导降水EOF的第一模态,SIC主导降水EOF的第二模态;2)北极海冰突变前,ENSO和SIC通过500 hPa经向波列,影响整个东亚地区的850 hPa风场,最终导致三极子型降水模态。突变后,ENSO通过500 hPa经向波列,影响华南地区的850 hPa风场,导致降水的偶极子空间模态,从而主导降水EOF的第一模态;同时SIC通过东亚地区500 hPa纬向波列,影响北方850 hPa风场,最终主导降水EOF的第二模态。3)北极海冰突变后,ENSO和SIC对东亚夏季降水的影响存在区域差异。北极海冰突变前,ENSO和SIC共同影响南北方降水;北极海冰突变后,SIC主要影响北方降水,ENSO主要影响南方降水。 相似文献
5.
本文简要综述了关于东亚夏季风和冬季风近几十年来的主要变化特征的若干研究结果,特别是关于其年代际变化方面.夏季风及夏季气候的主要变化特征有:1970年代末之后东亚夏季风的年代际时间尺度的减弱以及相应的我国夏季降水江淮流域增多而华北减少、1992年之后我国华南夏季降水增多、1999年之后我国长江中下游夏季降水减少而淮河流域夏季降水增多、东亚夏季风和ENSO之间的年际变化相关性存在不稳定性.而关于东亚冬季风与冬季气候的主要变化特征有:1980年代中期之后东亚冬季风及其年际变率减弱、1970年代中期之后冬季风和ENSO的年际变化相关性较弱、近年来的北极秋季海冰减少对北半球冬季积雪增多有显著贡献、东北冬季积雪在1980年代中期以后增多.与上述变化有关的极端气候和物候都发生了多方面的变化. 相似文献
6.
北半球冬季环流异常与ENSO的非线性关系 总被引：1，自引：0，他引：1
运用非线性典型相关分析（nonlinear canonical correlation analysis,简称NLCCA）方法,对热带太平洋海表温度异常（SSTA）场与北半球冬季海平面气压异常场（SLPA）进行非线性分析,以反映ENSO与北半球冬季环流异常之间的非线性关系。NLCCA的结果表明：从极冷到极暖期,北半球冬季SLPA场对ENSO的投影在各主成分所分别构成的平面或空间中分别形成一条直线和一条抛物线,说明北半球冬季环流异常与ENSO的相关包含线性和具有二次特征的非线性两部分。无论ENSO的冷、暖事件都能导致冰岛低压减弱,且西伯利亚高压、北美高压和北太平洋高压随SSTA的变化不对称,进一步证明了ENSO对北半球冬季环流异常的非线性影响,其中冰岛低压对于ENSO响应的非线性特征最强,而阿留中低压与ENSO则主要是线性相关。 相似文献
7.
A DIAGNOSIS OF THE INTERANNUAL VARIABILITY OF SEA SURFACE TEMPERATURE AND SURFACE WIND FIELD IN THE TROPICAL OCEANS AND ITS CORRELATIVE CHARACTERS WITH ENSO CYCLE* 
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下载免费PDF全文 Utilizing the NCEP/NCAR reanalysis monthly datasets,and based on the filter and standard deviation calculation,the interannual variability of sea surface temperature (SST) and 1000 hPa wind field for the tropical Pacific,Indian and Atlantic Oceans is investigated for the past 20 years (1979-1998).The characters of space-time evolution in SST anomalies (SSTA) for each ocean and corresponding wind anomaly field are acquired by using rotated principal component (RPC) and linear regression analysis methods.Using the method of correlation analysis.the characters of three tropical oceans correlated with ENSO are investigated.The contemporary correlation between the SSTA in the Indian Ocean and in the equatorial eastern Pacific is positive,and there is a weak negative correlation between the SSTA in the equatorial east Atlantic Ocean and in the equatorial eastern Pacific.The lead-lag correlation analysis indicates that the SSTA in the equatorial Indian Ocean lags the dominant Pacific ENSO mode by 3 months,and the SSTA in the equatorial Atlantic Ocean leads ENSO mode by 6 months.The ENSO-correlated components in tropical Indian Ocean and tropical Atlantic Ocean display much the same amount of total variance in each ocean,i.e..14% in the Indian Ocean and 12% in the Atlantic Ocean and the maximums are all above 40%. 相似文献
8.
Interdecadal shift in the relationship between the East Asian summer monsoon and the tropical Indian Ocean 总被引：7，自引：0，他引：7
In this work, the authors investigate changes in the interannual relationship between the East Asian summer monsoon (EASM) and the tropical Indian Ocean (IO) in the late 1970s. By contrasting the correlations of the EASM index (EASMI) with the summer IO sea surface temperature anomaly (SSTA) between 1953–1975 and 1978–2000, a pronounced different correlation pattern is found in the tropical IO. The SSTA pattern similar to the positive Indian Ocean Dipole (IOD) shows a strongly positive correlation with the EASMI in 1953–1975. But in 1978–2000, significant negative correlation appears in the northern IO and the IOD-like correlation pattern disappears. It is indicated that the summer strong IOD events in 1953–1975 can cause a weaker-than-normal western North Pacific (WNP) subtropical high, which tends to favor a strong EASM. In 1978–2000, the connection between the summer IOD and the WNP circulation is disrupted by the climate shift. Instead, the northern IO shows a close connection with the WNP circulation in 1978–2000. The warming over the northern IO is associated with the significant enhanced 500 hPa geopotential height and an anomalous anticyclone over the WNP. The change in the IO–EASM relationship is attributed to the interdecadal change of the background state of the ocean–atmosphere system and the interaction between the ENSO and IO. In recent decades, the tropical IO and tropical Pacific have a warmer mean SST, which has likely strengthened (weakened) the influence of the northern IO (IOD) on the EASM. In addition, due to the increase in the ENSO variability along with the higher mean equatorial eastern Pacific SST in 1978–2000, the influence of ENSO on the East Asian summer circulation experiences a significant strengthening after the late 1970s. Because the warming over the northern IO is associated with the significant warming in the equatorial eastern Pacific, the strengthened ENSO–EASM relationship has likely also contributed to the strengthened relationship between the northern IO and the EASM in 1978–2000. 相似文献
9.
北极海冰面积变化与大气遥相关型 总被引：4，自引：0，他引：4
本文综述了北极海注面积变化与大气遥相关型研究工作中的一些主要结果。诊断分析表明，北极海冰面积变化具有３－４年的振荡周期，大气中的遥相关型不仅与海冰面积变化的区域有关，还与海冰面积的振荡频率有关。海冰面积变化与大气遥相关型是互相维持的，一方的加强有利于另一方的加强，本文最后还对北极海冰和赤道中，东太平洋海温对北半年冬半年中纬度大气环流影响的相似性等问题进行了讨论。 相似文献
10.
基于太平洋海面温度（SST）、大气环流及青岛降水量资料,分析并发现了青岛汛期（6—9月）降水量与太平洋年代际振荡（PDO）指数存在重要联系。当PDO处于冷位相时,西北太平洋区SST偏高,北美沿岸以及热带中东太平洋区SST偏低,西太平洋副热带高压偏弱偏东,脊线偏北,东亚夏季风偏强,青岛汛期降水量偏多,反之偏少。定义了一个新的太平洋SST距平指数SSTI,该指数包含了西北太平洋与热带中东太平洋SST距平反相变化的协同影响,也包含了PDO与ENSO的协同影响。与PDO指数、西北太平洋及热带中东太平洋SST相比,该指数与青岛汛期降水量相关性更好,通常SSTI正指数对应着汛期西太平洋副热带高压脊线偏北,面积偏小、强度偏弱,东亚夏季风偏强,有利于青岛汛期降水量偏多,反之偏少。SSTI指数可作为青岛汛期降水量预测的指示因子。 相似文献
11.
Interdecadal Variability of the East Asian Winter Monsoon and Its Possible Links to Global Climate Change 下载免费PDF全文
下载免费PDF全文 DING Yihui LIU Yanju LIANG Sujie MA Xiaoqing ZHANG Yingxian SI Dong LIANG Ping SONG Yafang ZHANG Jin 《Acta Meteorologica Sinica》2014,28(5):693-713
This paper presents a concise summary of the studies on interdecadal variability of the East Asian winter monsoon (EAWM) from three main perspectives. (1) The EAWM has been significantly affected by global climate change. Winter temperature in China has experienced three stages of variations from the beginning of the 1950s: a cold period (from the beginning of the 1950s to the early or mid 1980s), a warm period (from the early or mid 1980s to the early 2000s), and a hiatus period in recent 10 years (starting from 1998). The strength of the EAWM has also varied in three stages: a stronger winter monsoon period (1950 to 1986/87), a weaker period (1986/87 to 2004/05), and a strengthening period (from 2005). (2) Corresponding to the interdecadal variations of the EAWM, the East Asian atmospheric circulation, winter temperature of China, and the occurrence of cold waves over China have all exhibited coherent interdecadal variability. The upper-level zonal circulation was stronger, the mid-tropospheric trough over East Asia was deeper with stronger downdrafts behind the trough, and the Siberian high was stronger during the cold period than during the warm period. (3) The interdecadal variations of the EAWM seem closely related to major modes of variability in the atmospheric circulation and the Pacific sea surface temperature. When the Northern Hemisphere annular mode/Arctic Oscillation and the Pacific decadal oscillation were in negative (positive) phase, the EAWM was stronger (weaker), leading to colder (warmer) temperatures in China. In addition, the negative (positive) phase of the Atlantic multi decadal oscillation coincided with relatively cold (warm) temperatures and stronger (weaker) EAWMs. It is thus inferred that the interdecadal variations in the ocean may be one of the most important natural factors influencing long-term variability in the EAWM, although global warming may have also played a significant role in weakening the EAWM. 相似文献
12.
The interannual variability of East Asian Monsoon and its relationship with SST in a coupled Atmosphere-Ocean-Land climate model 总被引：5，自引：1，他引：4
Wang Huijun 《大气科学进展》2000,17(1):31-47
1.IntroductionThelargestinterannualvariabilityassociatedwiththeENSOcycleexistsinmonsoonregionsliketheAfricanmonsoon,Australianmonsoon,Pan--AmericanmonsoonandAsianmonsoon(RopelewskiandHalpert,1987;WebsterandYang,1992;JuandSlingo,1995).OnebasicquestionishowtorepresenttheAsianmonsoonanditsvariability.WebsterandYang(1992)foundareasonableindexbyaveragingthezonalwindshearbetween850hpaand200hpaovertheSouthAsianregion(40--110E,0--20N)todescribetheSouthAsianmonsooncirculationanditsvariability.… 相似文献
13.
东亚冬季风的年代际变化及其与全球气候变化的可能联系 总被引：15，自引：2，他引：13
对近年来中外关于东亚冬季风(EAWM)年代际变化问题研究进展做了回顾和评述,主要包括以下3个方面内容:(1)东亚冬季风明显受到全球气候变化的影响,从20世纪50年代开始,中国冬季气温经历了一次冷期(从20世纪50年代延续到80年代初中期),一次暖期(从20世纪80年代初中后期延续到21世纪初)和近10-15年(约从1998年开始)出现的气候变暖趋缓期(也称气候变暖停顿期)。(2)东亚冬季风主要表现出强-弱-强3阶段的特征,即从1950年到1986/1987年,明显偏强;从1986/1987年冬季开始,东亚冬季风减弱;约2005年之后,东亚冬季风开始由弱转强。与东亚冬季风的年代际变化特征相对应,东亚冬季大气环流以及中国冬季气温和寒潮都表现出一致的年代际变化。(3)东亚冬季风的年代际变化与大气环流和太平洋海表温度(SST)的区域模态变化密切相关。当北半球环状模/北极涛动(NAM/AO)和太平洋年代际振荡(PDO)处于负(正)位相,东亚冬季风偏强(弱),中国冬季气温偏低(高)。此外,北大西洋年代尺度振荡(AMO)对东亚冬季风也有重要影响,在AMO负位相时,对应东亚冷期(强冬季风),正位相对应暖期(弱冬季风)。因而海洋的年代际变化是造成东亚冬季风气候脉动的主要自然原因,而全球气候变暖对东亚冬季风强度的减弱也有明显影响。 相似文献
14.
东亚季风指数及其与大尺度热力环流年际变化关系 总被引：24，自引：1，他引：23
将东西向海平面气压差与低纬度高、低层纬向风切变相结合 ,定义了东亚季风指数 ,该季风指数较好地反映了东亚冬、夏季风变化。其中 ,夏季风指数年际异常对西太平洋副热带高压南北位置变化和长江中下游旱涝具有较强的反映能力。分析表明 :东亚夏季风年际变化与印度洋 -西太平洋上空反 Walker环流及夏季越赤道南北半球间的季风环流呈显著正相关关系。在强、弱异常东亚夏季风年份 ,异常的 Walker环流在西太平洋上的辐合 (辐散 )中心在垂直方向不重合 ,高层 ( 2 0 0 h Pa)速度势与东亚夏季风显著相关区域位于西北太平洋上 ,该异常环流的高层的辐合 (辐散 )通过改变低层空气质量而影响夏季 50 0 h Pa西北太平洋副热带高压。采用 SVD分析进一步发现 :与海温耦合的异常 Walker环流在西太平洋上空的上升支表现出南北半球关于赤道非对称结构 ,亚澳季风区受该异常 Walker环流控制。因而 ,东亚季风与热带海气相互作用可直接通过这种纬向非对称的 Walker环流发生联系。 相似文献
15.
冬夏东亚季风环流对太平洋热状况的响应 总被引：9，自引：3，他引：6
冬夏隔季韵律关系一直是我国长期天气预报和短期气候预测的一个重要依据,然而迄今为止对它们之间的物理过程及成因机理并不十分清楚。利用NCEP/NCAR全球2.5°×2.5°网格月平均再分析资料,研究1951~2000年冬夏东亚季风环流异常变化与太平洋海面温度(SST)的关系及对关键海温区响应机理。研究指出:冬夏东亚季风环流隔季韵律关系及其年际变化与赤道东太平洋海面温度异常(SSTA)变化密切相关,冬季赤道东太平洋出现La Ni~na(El Ni~no)型的SST分布,有利冬、夏东亚季风环流加强(减弱),其影响过程通过赤道Walker环流强(弱)以及东亚地区Hadley环流强(弱)过程完成。冬季赤道东太平洋海温变化是冬、夏东亚环流季节以及年际变化的一个重要外强迫因子。 相似文献
16.
采用1950-2000年逐月观测的不同海域(全球、热带外、热带、热带印度洋-太平洋、热带印度洋及热带太平洋)海表温度分别驱动NCAR CAM3全球大气环流模式,进行了多组长时间积分试验,对比ERA-40和NCEP/NCAR再分析资料,讨论了这些海域海表温度异常对东亚夏季风年代际变化的影响。数值试验结果表明:全球、热带、热带印度洋-太平洋和热带太平洋海表温度变化对东亚夏季风的年代际变化具有重要作用,均模拟出了东亚夏季风在20世纪70年代中后期发生的年代际减弱现象,以及强、弱夏季风年代夏季大气环流异常分布的显著不同,这与观测结果较一致,表明热带太平洋是影响东亚夏季风此次年代际变化的关键海区;利用热带印度洋海表温度驱动模式模拟出的东亚夏季风在20世纪70年代中后期发生年代际增强现象,即当热带印度洋海表温度年代际偏暖(冷)时,东亚夏季风年代际增强(减弱),与热带太平洋海表温度变化对东亚夏季风年代际变化的影响相反;热带太平洋海表温度年代际背景的变化对东亚夏季风在20世纪70年代中后期的年代际减弱有重要作用。 相似文献
17.
Summary Based on analysis of NCEP reanalysis data and SST indices of the recent 50 years, decadal changes of the potential predictability
of ENSO and interannual climate anomalies were investigated. Autocorrelation of Nino3 SST anomalies (SSTA) and correlation
between atmospheric anomalies fields and Nino3 SSTA exhibit obvious variation in different decades, which indicates that Nino3
SSTA-related potential predictability of ENSO and interannual climate anomalies has significant decadal changes. Time around
1977 is not only a shift point of climate on the interdecadal time scale but also a catastrophe point of potential predictability
of ENSO and interannual climate. As a whole, ENSO and the PNA pattern in boreal winter are more predictable in 1980s than
in 1960s and 1970s, while the Nino3 SSTA-related potential predictability of the Indian monsoon and the East Asian Monsoon
is lower in 1980s than in 1960s and 1970s.
Received October 19, 1999 Revised December 30, 1999 相似文献
18.
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 %。 相似文献
19.
Reconstructing the long-term series of the East Asian summer monsoon (EASM) indices may help understand long-term variability of EASM and its associations with precipitation. In this study, the summer middle?Cupper tropospheric temperature over the Asian?CNorth Pacific sector is reconstructed from sea level pressure during the past 150?years, and then an atmospheric thermal contrast between Asia and the North Pacific, called the Asian?CPacific Oscillation (APO) index, is calculated from the reconstructed temperature. The results show that the APO phenomenon may occur in the reconstructed temperature fields, and its index has a significant positive/negative correlation with SST over the extratropical North Pacific/the tropical central?Ceastern Pacific in the past 150?years. The reconstructed summer APO index shows inter-decadal variability, with a positive phase in the 1870?C1890s, the 1920s, and the 1940?C1970s, indicating a stronger thermal contrast between Asia and the North Pacific, and with a negative phase in the 1860s, the 1900?C1910s, and the 1980?C1990s, indicating a weaker thermal contrast. Corresponding to a higher APO index in earlier decades of the twentieth century, there are more rainfall to the south of the Yangtze River and over North China and less rainfall over the Huaihe River valley. In the recent decades, however, more- and less-rain belts shifted southwards when the APO index is higher. During 1850?C1900, the reconstructed APO index also showed a significant positive correlation with precipitation in some regions of North China. 相似文献