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1.
A zonal domain primitive equation modeling system(ZDMS) is used to study the effects of the initial heating anomalies over the Tibetan Plateau and the western Pacific on the East Asian and the Chinese summer climate,the relative importance and the mechanisms are discussed.Results show that in spite of the different locations of the heating anomalies the influences of the two anomalyareas are much similar to each other when the scaling of the two areas is the same.The two areas of heating anomalies have their own affecting domains in which one is more important than the other.In the western Pacific the heating anomaly over the western Pacific is more evident and in the Tibetan Plateau area the heating anomaly over the Tibetan Plateau is more obvious.For the east part of China the effects of the two heating anomalies both exist and almost have the equal importance.The initial anomaly of the sea surface temperature(SST) over the western Pacific can be kept during the entire time integration while in the Tibetan Plateau it can not be maintained.  相似文献   

2.
The relationships between the summer rainfall in China and the atmospheric heat sources over the eastern Tibetan Plateau and the western Pacific warm pool were analyzed comparatively, using the NCEP/NCAR reanalysis daily data. The strong (weak) heat sou…  相似文献   

3.
利用Hadley中心提供的逐月海温资料、ERA-Interim再分析资料以及NOAA(National Oceanic and Atmospheric Administration)的逐月向外长波辐射(OLR)资料探讨了1979~2011年夏季青藏高原“湿池”的水汽含量与前期印度洋海温异常的关系,并对可能的原因进行了分析。结果表明,夏季青藏高原水汽(去趋势)EOF第二模态与前期印度洋海温存在密切的正相关,前期3~4月关键区(5°S~20°N,45°E~75°E)的海温异常可以作为夏季高原水汽的预测信号。在暖水年,赤道附近显著的东风异常对夏季高原水汽输送起到了至关重要的作用。500 hPa上副热带高压显著增强并西移,600 hPa上赤道附近为显著的异常东风,将水汽从西太平洋、南海、孟加拉湾向西输送到印度半岛,并在异常反气旋环流西侧的南风作用下,将水汽带向青藏高原。高层风场上,西太平洋地区辐合,青藏高原上空辐散。以上环流形势表明暖水年夏季青藏高原水汽偏多;冷水年则相反。就影响机制而言,前期春季印度洋海温显著偏暖,引起其上空异常的对流上升运动,驱动异常沃克环流从春到夏显著维持,副热带高压的季节性北跳和异常增强西移,有利于赤道东风异常的增强和西移,并经过水汽输送通道将水汽带向青藏高原上空。  相似文献   

4.
青藏高原影响亚洲夏季气候研究的最新进展   总被引:40,自引:6,他引:40  
文中回顾了近 10a来吴国雄等在青藏高原影响亚洲夏季气候研究方面的最新进展。通过分析东西风交界面的演变证明 ,由于青藏高原的春季加热 ,亚洲季风区对流层低层冬季盛行偏东风转变为夏季偏西南风最早发生在孟加拉湾东部 ,与其相伴随的激烈对流降水出现在其东面。因此孟加拉湾东部至中印半岛西部是亚洲季风最早爆发的地区。同时也指出盛夏伊朗高原和青藏高原加热所激发的同相环流嵌套在欧亚大陆尺度的热力环流中 ,从而加强了东亚的夏季风 ,加剧了中西亚的干旱 ;并通过其所激发的波动对夏季东亚的气候格局产生重要影响。文中还比较了夏季南亚高压的伊朗模态和青藏模态性质的异同及其对亚洲夏季降水异常分布的不同影响。  相似文献   

5.
利用资料诊断和全球大气原始方程模式(Intermediate General Circulation Model,IGCM),研究了2008年1月中国南方地区出现罕见的持续性雨雪事件的成因.结果表明,2008年1月大气非绝热加热场的主要异常出现在热带海洋、青藏高原及中亚地区以及北大西洋.用全球异常热源强迫IGCM得到的...  相似文献   

6.
海陆分布和地形对1998年夏季风爆发的热力影响   总被引:8,自引:9,他引:8  
应用1980-1995年5天平均的CMAP降水资料、美国NMC850hPa风、卫星反演的向外长波辐射(OLR)和上部对流层水汽亮温(BT)等资料分析比较了南海夏季风爆发前后的基本特征。结果发现:BT能够反映南海夏季风的爆发及其与周围地区降水的关系,但局地降水信息的反映不够具体;OLR能够比较好的反映热带海洋上的降水,但陆地上的低值OLR可能受到地形的影响,仅仅850hPa风场不能完全确定夏季风的爆发。南海季风转换区域定义在南海的中北部比较合适,这是因为南海夏季风爆发前就存在着长年位于南海南部的带海洋对流性雨带;南海夏季风爆发后西南季风气流和季风雨带从印度洋经孟加拉湾和南海伸向西北太平洋,开始了南亚和东亚夏季风的爆发过程。  相似文献   

7.
春季青藏高原大气热源与长江中下游盛夏高温的关系   总被引:1,自引:0,他引:1  
利用1961—2013年长江中下游地区盛夏(7—8月)日极端最高气温和NCEP/NCAR再分析逐日资料,分析了春季(4—5月)青藏高原大气热源特征,找到了影响长江中下游盛夏高温的热源关键区域,并就关键区大气热源对长江中下游盛夏高温的影响进行了诊断。结果表明:春季青藏高原主体中南部大气热源与长江中下游盛夏高温关系密切,当该区域大气热源偏弱(强),长江中下游盛夏高温日数偏多(少)的可能性大。当春季青藏高原关键区大气热源偏弱(强)时,春季南海到西太平洋暖池对流偏强(偏弱),南海上空为气旋性(反气旋性)异常环流,西太平洋副热带高压偏东(西),有利于南海夏季风爆发偏早(晚),往往有利于盛夏西太平洋副热带高压位置偏北(南),从而导致长江中下游盛夏高温日数偏多(偏少)。春季青藏高原关键区大气热源可以作为长江中下游盛夏高温的一个前期预报因子。  相似文献   

8.
The summer snow anomalies over the Tibetan Plateau (TP) and their effects on climate variability are often overlooked,possibly due to the fact that some datasets cannot properly capture summer snow cover over high terrain.The satellite-derived Equal-Area Scalable Earth grid (EASE-grid) dataset shows that snow still exists in summer in the western part and along the southem flank of the TP.Analysis demonstrates that the summer snow cover area proportion (SCAP) over the TP has a significant positive correlation with simultaneous precipitation over the mei-yu-baiu (MB) region on the interannual time scale.The close relationship between the summer SCAP and summer precipitation over the MB region could not be simply considered as a simultaneous response to the Silk Road pattern and the SST anomalies in the tropical Indian Ocean and tropical central-eastern Pacific.The SCAP anomaly has an independent effect and may directly modulate the land surface heating and,consequently,vertical motion over the western TP,and concurrently induce anomalous vertical motion over the North Indian Ocean via a meridional vertical circulation.Through a zonal vertical circulation over the tropics and a Kelvin wave-type response,anomalous vertical motion over the North Indian Ocean may result in an anomalous high over the western North Pacific and modulate the convective activity in the western Pacific warm pool,which stimulates the East Asia-Pacific (EAP) pattern and eventually affects summer precipitation over the MB region.  相似文献   

9.
Using the 1980-2010 winter GODAS oceanic assimilations, study is conducted of the winter heat content (HC) established in the subsurface layer (5 to 366 m in depth) over the western Pacific warm pool (WP), followed by investigating the HC spatiotemporal characteristics, persistence and the impacts on the climate anomalies of neighboring regions. Results are as follows: 1) the pattern of integral consistency is uncovered by the leading EOF1 (PC1) mode of HC interannual variability, the year-to-year fluctuation of the time coefficients being well indicative of the interannual anomaly of the WP winter subsurface-layer thermal regime. The HC variation is bound up with ENSO, keeping pronounced autocorrelation during the following two seasons and more, with the persistence being more stable in comparison to SSTA in the equatorial middle eastern Pacific; 2) the winter HC anomalies produce lasting effect on the WP thermal state in the following spring and summer and corresponding changes in the warm water volume lead to the meridional transport and vertical exchange of warm water, which exerts greater impacts upon the sea surface temperature/heat flux over the warm pool per se and neighboring regions, especially in the Philippine Sea during the posterior spring and summer; 3) the increase in the winter HC corresponds to the spring OLR decrease and richer precipitation over the waters east to the Philippine Sea and the resultant convective heating anomalies are responsible for the rise of geopotential isobaric surfaces over tropical and subtropical western North Pacific, thereby producing effect on the western Pacific subtropical high (anomaly). Subsequently, the sea-surface heat flux exchange is intensified in the warm pool, a robust anomalous cyclone shows up at lower levels, air-sea interactions are enhanced and abnormal convective heating occurs, together making the winter HC anomalies even more closely associated with the variation in the summer subtropical high. As a result, the WP winter HC can be used as an effective predictor of the variation in spring/summer western Pacific subtropical high and the strength of summer monsoon over the northwestern Pacific.  相似文献   

10.
The impact of surface sensible heating over the Tibetan Plateau(SHTP) on the western Pacific subtropical high(WPSH)with and without air–sea interaction was investigated in this study. Data analysis indicated that SHTP acts as a relatively independent factor in modulating the WPSH anomaly compared with ENSO events. Stronger spring SHTP is usually followed by an enhanced and westward extension of the WPSH in summer, and vice versa. Numerical experiments using both an AGCM and a CGCM confirmed that SHTP influences the large-scale circulation anomaly over the Pacific, which features a barotropic anticyclonic response over the northwestern Pacific and a cyclonic response to the south. Owing to different background circulation in spring and summer, such a response facilitates a subdued WPSH in spring but an enhanced WPSH in summer. Moreover, the CGCM results showed that the equatorial low-level westerly at the south edge of the cyclonic anomaly brings about a warm SST anomaly(SSTA) in the equatorial central Pacific via surface warm advection.Subsequently, an atmospheric Rossby wave is stimulated to the northwest of the warm SSTA, which in turn enhances the atmospheric dipole anomalies over the western Pacific. Therefore, the air–sea feedbacks involved tend to reinforce the effect of SHTP on the WPSH anomaly, and the role of SHTP on general circulation needs to be considered in a land–air–sea interaction framework.  相似文献   

11.
利用ERA-Interim和APHRO_MA资料分析了1979~2007年间青藏高原西部春季(3~5月)降水的年代际变化趋势及可能原因。结果表明,青藏高原西部局部区域春季降水呈显著减少趋势,降水的变化趋势与其西南部辐合上升运动及阿拉伯海北部水汽含量变化存在联系。发现研究区春季降水增加时伴随其西南部显著的辐合上升异常,同时高层(500 hPa)位势高度场负异常中心与环流的气旋式正异常中心一致,而低层(850 hPa)的辐合上升异常相对较弱;研究区春季降水增加同时伴随阿拉伯海北部至研究区西南部的高、低层比湿正异常,其中低层的比湿正异常更为显著,其正异常中心均位于阿拉伯海北部。上述区域的水汽输送能解释研究区春季降水55.3%的变化,同时两者的变化趋势具有很好相关性。研究显示1979~2007年间研究区春季降水呈下降趋势主要是由阿拉伯海北部低层向印度次大陆水汽输送减少,以及研究区南部高层辐合上升运动减弱造成的。青藏高原西部春季降水变化趋势和相关区域水汽变化的一致性,可以为分析高原气候变化提供依据。  相似文献   

12.
In this work, the SCSMEX data are used to diagnose and compare the local land-sea thermal conditions, with the focus of discussion on possible influences of thermal forcing of the western Pacific and the Tibetan Plateau on the onset and development of summer monsoon in 1998. Results show a close relationship between the distribution of the heat sources and the land-sea contrast. Due to the blocking effect of terrain, main maximum zones of the heat sources in areas with more evident north-south land-sea contrast are more obviously southward located than those exclusively with oceans. The surface heating is characterized with apparent seasonal variation and difference between land and sea. The relationship between the western Pacific and the onset of summer monsoon is reflected in the variations of the sea surface temperature (SST) and the latent heat. The influence mechanism of the Tibetan Plateau during the summer monsoon is different: it is dominated by sensible heating during the South China Sea monsoon and by condensed latent heating during the Indian monsoon.  相似文献   

13.
我国西南地区秋季降水年际变化的空间差异及其成因   总被引:3,自引:0,他引:3  
刘扬  刘屹岷 《大气科学》2016,40(6):1215-1226
使用1980~2010年全国站点降水资料、ERA-Interim再分析环流资料、哈德莱海表温度资料,运用聚类分析和旋转经验正交函数分解,对西南地区的秋季降水按照其年际变化规律进行分区,进而分析影响各区域降水变化的物理过程和机理。结果表明:西南地区被分为东、西两个区域。西南东、西区域秋季降水的年际变化、显著周期、旱涝异常年份、相关的环流系统都有明显差异。西南东部秋季降水主要与热带海温异常有关,受低纬度环流影响。当赤道东太平洋为暖海温异常,热带印度洋为西正东负的偶极子型海温异常时,分别激发出西北太平洋反气旋和孟加拉反气旋,共同向西南东部输送水汽,造成西南东部降水偏多。西南西部降水在秋季三个月份与不同的环流形势对应:9月降水由中南半岛反气旋输送的暖湿气流决定;10月降水受高原以东反气旋环流和孟加拉湾低槽共同影响;11月降水主要受中高纬环流异常的影响,与斯堪的纳维亚遥相关存在显著负相关。  相似文献   

14.
杨莲梅  张庆云 《高原气象》2007,26(3):435-441
利用1980—2004年NCEP/DOE新再分析月平均资料及我国225个测站1980—2004年月降水量资料,通过诊断分析,研究了南疆夏季降水异常的环流和高原地表潜热通量特征。结果表明:南疆夏季降水偏少年,南亚高压西部偏强,西风急流位置偏北,500 hPa中高纬环流经向度减弱,伊朗高压偏北、偏东,西太平洋副热带高压偏西、偏南;降水偏多年则相反。南疆夏季降水偏少年,高原北部和南疆地区为下沉的垂直环流距平,Ferrell环流增强;降水偏多年则相反。南疆夏季降水偏少年和偏多年的前期冬春季开始孟加拉湾、青藏高原和南疆地区地表潜热通量具有相反的变化,南疆夏季降水与高原北部地表潜热通量呈显著正相关,与南部地表潜热通量呈反相关关系。  相似文献   

15.
副热带高压研究回顾及对几个基本问题的再认识   总被引:44,自引:3,他引:41  
刘屹岷  吴国雄 《气象学报》2000,58(4):500-512
文中在回顾有关副热带高压研究的基础上 ,指出传统的观念在东太平洋副热带高压和西太平洋副热带高压的关系、下沉运动和副热带高压的形成、热带加热异常与副热带高压异常的关系、副热带高压与其周边系统的关系等问题上存在一定的局限。并根据近期的研究成果对上述问题给出新的认识。最后文中展望了在副热带高压的研究中需进一步深入的几个方面 :不同纬度相互作用、青藏高原的作用、时间尺度 -内部动力过程和外界强迫的相对重要性、非线性过程和角动量平衡问题。  相似文献   

16.
谢志昂  段安民 《大气科学》2017,41(4):811-830
通过多源资料诊断分析,本文讨论了盛夏(8月)青藏高原大气热源与菲律宾海对流活动之间的联系及可能的机制。结果表明,与青藏高原热源相联系的环流形势在夏季各月明显不同,因此对夏季青藏高原热源的影响应当分月讨论。在夏季各月中,菲律宾海对流活动与青藏高原热源在8月份的联系最为紧密,二者存在显著的反相关关系。而8月青藏高原热源、菲律宾对流活动、西太平洋副热带高压(简称西太副高)、印度季风低压、南亚高压、西风带槽脊和西北太平洋季风环流存在相互耦合的过程。青藏高原热源与菲律宾海对流活动之间联系的机制为:菲律宾海对流弱(强)年,西太副高偏西(东)偏南(北),西北太平洋季风环流减弱(加强),印度季风低压减弱(加强),西风带南压(北抬),又加之副高西侧有强(弱)的水汽输入,兼以高层南亚高压加强(减弱),使得高原南部降水显著增强(减弱),高原热源整体加强(减弱),高原热源的加强(减弱)又造成了高原南部到东亚区域低层西南(东北)风异常,又利于西太副高偏西(东)偏南(北),从而造成菲律宾海对流减弱(加强)。这一机制在高原热源强弱年均有表现,但强年表现得更为显著,并在个例中也有所体现,说明盛夏青藏高原热源异常和菲律宾海对流异常存在显著的相互作用。  相似文献   

17.
The current progresses in the study of impacts of the Tibetan Plateau on Asian summer climate in the last decade are reviewed. By analyzing evolution of the transitional zone between westerly to the north and easterly to the south (WEB), it is shown that due to the strong heating over the Tibetan Plateau in spring, the overturning in the prevailing wind direction from easterly in winter to westerly in summer occurs firstly over the eastern Bay of Bengal (BOB), accompanied with vigorous convective precipitation to its east. The area between eastern BOB and western Indo-China Peninsula thus becomes the area with the earliest onset of Asian monsoon, which may be referred as BOB monsoon in short. It is shown that the summertime circulations triggered by the thermal forcing of the Iranian Plateau and the Tibetan Plateau are embedded in phase with the continental-scale circulation forced by the diabatic heating over the Eurasian Continent. As a result, the East Asian summer monsoon is intensified and the drought climate over the western and central Asian areas is enhanced. Together with perturbations triggered by the Tibetan Plateau, the above scenarios and the associated heating have important influences on the climate patterns over Asia. Furthermore, the characteristics of the Tibetan mode of the summertime South Asian high are compared with those of Iranian mode. Results demonstrate that corresponding to each of the bimodality of the South Asian high, the rainfall anomaly distributions over Asia exhibit different patterns.  相似文献   

18.
利用改进的NCAR CCM3气候模式, 研究了1992年西北太平洋持续冷海温对东亚初夏季节大气环流的影响。西北太平洋冷海温不利于初夏东亚南支西风急流季节性北移, 引起亚洲东部沿海低槽明显加深, 东亚大槽平均高度场降低了4.66 dagpm, 从而也不利于西太平洋副热带高压的西伸加强。西北太平洋冷海温还不利于我国大陆初夏温度场回升, 特别是引起我国东北地区近地面温度下降2~5 ℃, 是影响东北冷夏现象的重要原因之一。模拟结果表明, 1992年初夏江淮入梅期较常年偏晚, 降水异常偏少, 与紧邻东亚大陆的西北太平洋持续冷海温有关。  相似文献   

19.
Based on NCEP/NCAR reanalysis monthly data,the relation between the surface sensible heat flux,(SHTFL) in the Tibetan Plateau and its vicinity and the East Asian winter monsoon is revealed as follows:on the inter-annual and longer time scales,the difference between SHTFL anomalies in the east and southern slope of the Tibetan Plateau last spring has influence on the East Asian winter monsoon,that is,SHTFL anomaly in the east of the Tibetan Plateau was positive and that in the southern slope was negative last spring,then the East Asian winter monsoon would become more vigorous,and vice versa.Both the most significant period of the difference between SHTFL anomalies in the east and southern slope of the Tibetan Plateau and that of the East Asian winter monsoon index are 2 to 4-year time scales.On the 2 to 4-year time scales,the heterogeneous spatial distribution of SHTFL anomalies in the east and southern slope of the Tibetan Plateau last spring has effect on the East Asian winter monsoon,after SHTFL anomaly in the east of the Tibetan Plateau was positive and that in the southern slope was negative last spring,then the East Asian winter monsoon would be more powerful,and vice versa.The lag influence of the difference of SHTFL anomalies in the east and southern slope of the Tibetan Plateau on the East Asian winter monsoon brings into effect mainly on 2 to 4-year time scales.In the end an reasonable explanation for their relationship has been discussed.  相似文献   

20.
孙畅  王子谦  杨崧 《大气科学》2019,43(2):350-360
基于全球降水气候中心(GPCC)和全球降水气候计划(GPCP)的降水数据及ERA-interim再分析资料,分析了1979~2012年冬季青藏高原(简称高原)西侧地区降水的基本特征及影响其年际变率的潜在因子。结果表明高原冬季降水主要发生在其西侧地区且为全区变化一致型,降水所需的水汽主要来自上游地区,从该区域的西边界输入。然而,高原西侧地区冬季降水的年际变率主要由水汽输送的动力过程所决定,表现为高原西侧的西南风异常。此外,高原西侧冬季降水的年际变率与其上游典型的大气内部变率北大西洋涛动和北极涛动相关性不强,而与赤道西印度洋和热带中东太平洋的海温显著相关。热带中东太平洋海温异常通过影响大气环流变化,在印度洋北部激发一个反气旋式的环流异常,使得高原西侧地区出现异常西南风,从而加强了水汽通量输送的动力作用。同时在赤道异常东风的作用下,暖水也向印度洋西部输送堆积。赤道中东太平洋海温的异常可进一步导致西风急流发生南北移动,从而也在一定程度上影响了高原西侧冬季水汽输送以及降水的年际变率。  相似文献   

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