高原季节转换时期大气环流变化特征

利用1961～ 2007年NCEP/NCAR的再分析逐日资料,分析高原主体上空大气环流的季节变化和受到高原影响的东亚大型环流系统的季节变化,以此证明本文得到的“高原普适性划分方法”的合理性.得到的初步结论概括如下：高原主体上空的位势高度、风场、高空温度、降水的季节变化和高原普适性季节划分方法划分的高原四季变化一致,高原南亚高压、副热带高压、副热带西风急流的三个特征指数季节变化和高原普适性季节划分方法划分的高原四季变化一致,这些结论都说明高原普适性季节划分方法划分的高原四季是合理的;风场季节率（500hPa、100hPa）显著区随高度升高向赤道靠近,风场季节率的变化主要和东亚季风的变化有关,大气环流系统季节率的显著说明了大气环流的季节变化,同时也证明了高原普适性季节划分方法的合理性.     

青藏高原地面感热对北半球大气环流和中国气候异常的影响

在青藏高原地面感热通量的基本气候特征以及异常变化的空间结构和时间演变趋势研究的基础上,进一步就高原地面感热异常对北半球大气环流和中国气候异常的影响进行诊断研究,并利用IAP2-LAGCM对青藏高原地面感热异常的影响进行了数值试验.结果表明:冬季地面感热在青藏高原西部、藏南谷地、横断山地区异常偏强,中、东部异常偏弱时,可使北半球500 hPa高度场表现出较明显的EU型和PNA型;高原西部、青海中北部异常偏弱,高原中部及东南部异常偏强时,使北半球100 hPa高度场的年际差异加强;西部、南部为正,柴达木及青海东部地区为负时,则新疆南部、西北东部及江南地区少雨,全国大部地区气温偏高.夏季高原地面感热通量距平特征为西南、藏南谷地、横断山区偏强,高原大部(中心在青海南部)异常偏弱时,则500"a高度场上青藏高原南部(孟加拉湾)高度偏高,高原北部高度偏低,负值区在帕米尔;当感热通量距平特征为高原西南、藏南谷地、横断山区偏弱,高原大部异常偏强时,有利于南亚高压的建立与维持;当地面感热通量呈南正北负距平差异时,长江上游、黄河源头及西北地区东部和东北部分地区降水量比常年偏多,气温偏低,中国东部、南部降水偏少,气温偏高.通过数值模式进行的敏感性试验证实了大气环流及区域气候变化对青藏高原地面感热总体异常的响应.       

Sensitivity of East Asian climate to the progressive uplift and expansion of the Tibetan Plateau under the mid-Pliocene boundary conditions

A global atmospheric general circulation model has been used to perform eleven idealized numerical experiments, i.e., TP10, TP10, .., TP100, corresponding to different percentages of the Tibetan Plateau altitude. The aim is to explore the sensitivity of East Asian climate to the uplift and expansion of the Tibetan Plateau under the reconstructed boundary conditions for the mid-Pliocene about 3 Ma ago. When the plateau is progressively uplifted, global annual surface temperature is gradually declined and statistically significant cooling signals emerge only in the Northern Hemisphere, especially over and around the Tibetan Plateau, with larger magnitudes over land than over the oceans. On the contrary, annual surface temperature rises notably over Central Asia and most parts of Africa, as well as over northeasternmost Eurasia in the experiments TP60 to TP100. Meanwhile, the plateau uplift also leads to annual precipitation augmentation over the Tibetan Plateau but a reduction in northern Asia, the Indian Peninsula, much of Central Asia, parts of western Asia and the southern portions of northeastern Europe. Additionally, it is found that an East Asian summer monsoon system similar to that of the present initially exists in the TP60 and is gradually intensified with the continued plateau uplift. At 850 hPa the plateau uplift induces an anomalous cyclonic circulation around the Tibetan Plateau in summertime and two anomalous westerly currents respectively located to the south and north of the Tibetan Plateau in wintertime. In the mid-troposphere, similarto-modern spatial pattern of summertime western North Pacific subtropical high is only exhibited in the experiments TP60 to TP100, and the East Asian trough is steadily deepened in response to the progressive uplift and expansion of the Tibetan Plateau.     

1956年1月到3月上旬亚洲上空大气环流的结构

根据1956年1月到3月上旬亚洲地区高空资料,对亚洲大陆上空的大气环流进行了探讨。作者得出了下列的事实: 1)在上述时间期限内的平均情况表明,亚洲大陆上空存在着二支急流。这二支急流在东经140°经度上已经汇合。 2)二支急流在东亚部分都表现有向东加速的现象。南支急流自东经75°就开始明显地向东加速。而北支急流的加速自东经100°附近才开始。 3)东亚大陆上大气的斜压性主要是集中在高原的附近。 另外对上述现象也作了一些初步的研究。作者认为西藏高原的存在对大气环流有下列三方面的影响: 1)高原加强了大气的斜压性,并且在高原南方形成垂直环流。因而强烈的加速了南支急流。 2)高原的存在使得南北二支急流在其东侧互相接近,显然地影响了急流的加速。 3)高原保证了南支急流强大而且稳定,这就是说每天每年同季的变化都小。     

夏季青藏高原和热带印度洋热力异常对塔里木盆地夏季降水的影响

基于1979～2017年欧洲中期天气预报中心(ECMWF)全球大气数值预报再分析资料ERA-Interim提供的地表潜热及大气环流再分析资料和英国Hadley气候预测和研究中心提供的全球逐月海表温度格点资料以及新疆气象信息中心提供的塔里木盆地26个站逐月降水资料,研究了夏季青藏高原和热带印度洋热力异常对塔里木盆地夏季降...     

THE FORMATION AND THE DEVELOPMENT OF CAMS TWO-DIMENSIONAL DYNAMICAL-PHYSICAL CLIMATE MODEL

In the paper,we have developed a 2-D physical-dynamical coupled climate model.Some sensitive experiments have been done by use of this model.First of all,we have studied the effects of different results by two radiational calculation schemes on circulation variation.The calculated results have shown that the different radiation parameterization schemes give different results,therefore the variational effects of wind,temperature,and humidity field are presented on the medium-range circulation variation.Besides,we have also studied the role of the meridional eddy momentum fluxes in formation of the monsoon over East Asia.The results of study have shown that on the average,the roles of meridional eddy flux of momentum formative processes of monsoon which is added to momentum equations by using the scheme of moist process parameterization with plateau are manifest.     

青海南部地区初冬雪灾变化及环流特征

利用青海南部地区1961~2004年气温、降水、积雪等资料,分析了初冬雪灾变化及环流特征。结果表明:青海南部地区初冬降雪量呈缓慢减少的变化趋势,平均积雪量变化与年及其它季相比,呈微弱的减少趋势,平均积雪量与气温呈反相关,而与降雪量呈正相关;影响青海南部地区初冬降雪的主要天气系统是西风带南北槽结合类、移动性高原槽类、高原低涡类、高原切变类、孟加拉湾风暴类;典型多雪(少雪)年高原及南亚与中亚地区850 hPa温度距平场配置为“南正北负”(“南负北正”)型5、00 hPa高原与东部沿海地区距平分布为“西低东高”(“西高东低”)型。     

两种厄尔尼诺类型期高原地区大气环流的对比分析

本文利用NCEP/NCAR再分析资料,分析了增温区域不同的两类El－Nino事件各阶段的特征,及其次年夏季高原地区的风场、温度场以及高原上空的南亚高压的高度场分布特征。结果表明:对风场环流的不同影响主要表现在:从垂直剖面图来看EP型整体都是东风增强,而CP型在对流层的中下层为西风增强,上层为东风增强;200hPa风场EP型高原上空为异常东风,而CP型为一异常切变线,北边异常东北风,南边异常东南风;500hPa风场EP型表现为异常东北风,CP型为异常东南风。对温度场的不同影响主要表现在:EP型在高原上空对流层中层和高层各有一个负异常中心,而CP型只在中层有一个负异常中心;对南亚高压的不同影响主要表现在:EP型南亚高压中心位置偏东南,而CP型南亚高压中心位置则偏北。      

The atmospheric heat source over the Bolivian plateau for a mean January

The atmospheric heat sources of large plateaus strongly influence the general circulation particularly in the summer season. The Bolivian plateau and the adjacent areas affect the upper tropospheric flow in a typical summer month by developing an anticyclone and deflecting the prevailing westerlies. The plateau initially warms the atmosphere through sensible heating and then through latent heating as thunderstorms develop.The atmospheric heat source over the Bolivian and adjacent plateau was computed employing conventional surface and satellite radiation data for the mean January 1979. Because of a lack of direct ground temperature data, the surface radiation was estimated following an empirical formula devised for some earlier Tibetan studies.The results revealed that the latent heating developing in the eastern and northeastern part of the plateau is the biggest contributor to the atmospheric heat source (500 W m^-2). A comparison of these results against similar recent results from Tibet showed that the atmospheric heat source in South America is stronger than that over Tibet, primarily because of increased rainfall over Bolivia.     

青藏高原积雪对中国夏季风气候的影响

利用SVD等方法对青藏高原积雪与中国区域降水的关系作了诊断分析。并用区域气候模式（RegCM2）对高原积雪的气候效应进行了模拟。结果表明:青藏高原积雪对中国夏季风气候的影响是显著的。积雪的增加会明显减弱亚洲夏季风的强度,使华南的降水减少,江淮流域的降水增多。高原冬季积雪深度的增加,比积雪面积的扩大和春季积雪深度的增加对后期气候的影响更大。     

高原涡与西南涡相互作用引发MCC暴雨的形成机制分析

使用常规观测资料、ERA-Interim再分析资料和卫星资料,以2014年7 月8-10 日西南涡和高原涡相互作用引发MCC 产生大暴雨的天气过程为例,分析了两涡作用导致大暴雨的形成机制.结果表明:相互作用前期,两涡涡心间距较远,在500 hPa 高度上两者同处于青海南部的气旋及其向南延伸的低槽前.约24 h 后,高原...     

一次东移型高原切变线过程的扰动动能特征

利用NCEP FNL(1°×1°)全球分析资料,采用动能梯度的定义和扰动动能方程,对2014年8月25—27日初生于青海省东南部之后东移到四川省中部产生天气影响过程的高原切变线进行了能量诊断分析。结果表明:在高原切变线发生发展时,切变线的位置和强的地转偏差及动能梯度大值区相对应,动能梯度模值的水平、垂直分布和相应的散度分布一致,可以反映切变线的基本结构特征;引入动能梯度有助于从能量变化视角来理解高原切变线的发展演变。扰动动能大值区的分布和切变线的走向一致,在切变线发展初期,扰动动能明显增大。扰动动能平流项和正压转换项的值都比较小,不足以反映切变线演变过程中的能量变化,而斜压转换项和扰动位势平流项是扰动动能收支的主导项;在切变线成熟阶段,扰动有效位能向扰动动能的转换最大,斜压转换项是高原切变线发展过程中能量转换的重要途径,有利于切变线上的上升运动加强。扰动动能趋势项可以较好预示切变线的发展态势,扰动非地转位势通量及其散度对高原切变线的生消及移动具有较好的指示意义。     

The Dynamic Plateau Monsoon Index and Its Association with General Circulation Anomalies

Based on monthly ECMWF reanalysis-Interim(ERA-Interim) reanalysis data,along with monthly precipitation and temperature data,the Dynamic Plateau Monsoon Index(DPMI) is defined.The results of a contrast analysis of the DPMI versus the Traditional Plateau Monsoon Index(TPMI) are described.The response of general circulation to northern Qinghai-Xizang Plateau summer monsoon anomalies and the correlation of the DPMI with general circulation anomalies are investigated.The results show that,the DPMI reflected meteorological elements better and depicted climate variation more accurately than the TPMI.In years when the plateau summer monsoon is strong,the low over the plateau and the trough near the eastern coast of Asia are deeper and higher than normal over South China.This correlation corresponds to two anomalous cyclones over the plateau and the eastern coast of Asia and an anomalous anticyclone in South China.The plateau and its adjacent regions are affected by anomalous southwesterly winds that transport more moisture to South China and cause more precipitation.The lower reaches of the Yangtze River appear to receive more precipitation by means of the strong westerly water vapor flow transported from the "large triangle affecting the region".In years when the plateau summer monsoon is weak,these are opposite.The plateau monsoon is closely related to the intensity and position of the South Asian high,and the existence of a teleconnection pattern in the mid-upper levels suggests a possible linkage of the East Asian monsoon and the Indian monsoon to the plateau summer monsoon.     

青藏高原大地形高度变化对东亚地区定常扰动能源转换的影响

利用CAM3（Community Atmosphere Model version 3）模式和ERA-Interim再分析数据研究了对流层中青藏高原大地形对东亚地区定常扰动能量源的影响。在冬季对流层中东亚地区的定常扰动的能量源地主要有两个,分别是高原北部的东亚地区和高原下游的西太平洋地区。高原高度增加时,对流层整层东亚地区斜压发展随高原高度增高而减弱,西太平洋地区斜压发展增强。定常扰动的正压发展与斜压发展的位置相似,但是明显的要比定常扰动的斜压发展弱。随着高原高度升高,在对流层中高原北部的东亚地区正压发展先减弱后增强,而在高原下游的西太平洋地区随高原高度增高正压发展一直增强。在冬季对流层中定常扰动的总能量发展与定常扰动的斜压发展一致,这样的发展趋势说明了冬季东亚地区和西太平洋地区定常扰动在对流层中的能量发展主要是斜压性引起的。     

青藏高原大气热源及其影响的研究进展

青藏高原及其热源效应对东亚以及全球的天气气候起着举足轻重的作用。青藏高原大气热源及其影响的相关研究有助于进一步加深对青藏高原大气热源及其影响的认识,提高高原地区天气系统发生发展的预报能力,提升高原地区降水的预报水平。本文较为系统地梳理了青藏高原大气热源的相关研究,涉及青藏高原大气热源的获取与特征,包括青藏高原大气热源的计算和青藏高原大气热源的时空分布及演变特征;青藏高原大气热源对季风、对降水的影响;青藏高原大气热源对天气系统的影响和作用,包括青藏高原大气热源对南亚高压、西太平洋副热带高压、高原低涡以及高原切变线的影响。在总结已有研究进展和成果的基础上,对今后青藏高原大气热源研究做出一定展望,提出值得进一步加强研究的方面。     

Study of the Simultaneous Physical Retrieval Method for Meteorological Parameters over the Continental Plateau of China

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青藏高原夏季带状MCSs的分类以及形成原因

利用2007-2011年夏季TBB（black body temperature）资料筛选出夏季青藏高原地区特征比较稳定的带状MCSs加以归类,结合NCEP资料及后向轨迹模型对其成因进行逐类探讨。结果表明,特征稳定的带状MCSs共有37例,可以按形状分为三类：北凸型、南界型和纬向型,其中北凸型发生得最多,纬向型最少。整个夏季有接近30％的时间,特别是在7月有近50％的时间都出现这种稳定的带状MCSs。高层南亚高压以及高空急流和低层500hPa切变线辐合及其南侧的高温高湿是带状MCSs生成的主要原因。500hPa上,纬向型带状MCSs一般发生在高原南北两侧较平直的东、西风气流中;北凸型发生时,高原北部为平直的西风气流,孟湾为较强的槽,高原东、南部受西南偏南气流影响;南界型时高原一般为西北气流,南侧有较强的孟湾气旋控制。围绕高原有4个水汽的辐散源地,带状MCSs对流区的水汽主要通过高原南侧和高原东南部的辐散源地进入对流区。     

夏季东亚大气环流的研究

夏季东亚大气环流的研究，一直是我国气象科学研究的重要课题之一。本文对东亚大气环流季节性转换、东亚大气环流的主要活动中心和青藏高原对东亚大气环流的作用等的研究进展，从观测事实、理论与模拟及其应用等方面进行了简单的评述。最后对今后夏季东亚大气环流研究的发展，提出了某些建议。     

夏季青藏高原对于南亚平均季风环流形成与维持的热力作用

本文应用一个包括Rayleigh摩擦、Newton冷却及水平涡旋热力扩散的定常准地转34层球坐标模式来研究青藏高原对于南亚季风环流形成与维持的热力作用。计算结果表明:在北半球夏季,只考虑高原的地形强迫作用是不能形成南亚高压与南亚季风环流的,而青藏高原上空的非绝热加热对于南亚高压与南亚平均季风环流的形成与维持起了重要作用。计算结果还表明了青藏高原的非绝热加热对于形成一支横跨印度次大陆直到日本南部的强西南风带同样也起了重要的作用。      

THE IMPACT OF RADIATIVE PROCESSES ON THE ONSET OF SUMMER MONSOON——NUMERICAL EXPERIMENTS

Two numerical experiments were performed by using ECMWF limited area model in order to assess theimpact of radiative processes on the onset of summer monsoon.The control experiment includes all model physicsand the other experiment is exclusive of radiative processes.The simulated results show that the radiativeprocesses enhanced the monsoon circulation and the associated vertical circulation over South Asia.Especiallyover the Qinghai-Xizang Plateau,the build-up of the plateau monsoon depression and the beginning of the plat-eau rainy season are highly dependent upon the radiative processes.Through the radiation-cloud interaction,the “moist processes” were enhanced over land.More latent heatwas released.The feedback of the physical processes caused the strengthening of the monsoon circulation oversouthern Asia.