MM5对中全新世时期中国地区气候的模拟研究

MM5模式结果与地质记录的对比表明,这个模式系统可以较好地模拟中全新世时气候的变化,特别是模式模拟的降水变化与地质记录吻合得较好.区域模式的结果比全球模式结果有所改进.模式结果显示:与现代相比,中全新世时,中国地区的气温升高,夏季升温超过冬季.同时,中国的内蒙古东部地区、东北地区和华北地区降水显著增加;而中国的华东、华中、华南和西南地区降水减少.中国东部30°N以北地区夏季风增强;中国东部的冬季风减弱.从一系列敏感试验结果,可以发现:在中全新世时,中国地区的气温、风场和降水的变化主要受大尺度环流背景场变化的影响,其对降水变化的影响超过50%.其次受地表状况和植被变化的影响,植被的变化主要影响中国东部地区,使得在冬季和夏季中国地区均升温;而且,对华北部分地区降水变化的影响最大超过25%.地球轨道的变化使得中全新世时太阳辐射的季节变化较大,造成中全新世时中国地区在冬季降温,在夏季升温;同时,对东北和华北地区的降水有重要影响,其影响与植被变化的影响相当.中全新世时,大气中CO2的体积混合比为280×10-6,CO2的变化使得中伞新世时气温降低,但量级较小.影响中全新世时中国地区气候变化的因子,按影响程度由大到小的排序为:大尺度环流背景场、植被变化、地球轨道参数变化和CO2浓度变化.     

Modeling the East Asian climate during the last glacial maximum

Climatologists have been paying much attention to the global and regional climatic charac-teristics during the LGM. A lot of paleodata were obtained in East Asia during the LGM[1—5] and laid the firm foundation of reconstructing East Asian paleoclimate t…     

青藏高原大气热量的简单计算方法及其应用

利用1961-1995年青藏高原及其邻近地区198个地面站月平均常规观测资料与青藏高原大气热量(〈Q1〉)资料,建立了一种计算青藏高原大气热量的简便方法.利用计算出的大气热量分析了各个季节青藏高原各地区〈Q1〉的气候特征,以及冬季高原〈Q1〉与春季大气环流场的关系.结果发现,各个季节高原东北部地区大气热量值都小于南部地区;高原各区大气热量在20世纪70年代到80年代初都表现出了显著的上升趋势.高原冬季热源与春季高原周围地区的位势高度场存在着明显的负相关,气候模拟证实了冬季高原地区热源变化对春季东亚大气环流的这种影响.     

INTERANNUAL VARIATION OF INDEX OF EAST ASIAN LAND-SEA THERMAL DIFFERENCE AND ITS RELATION TO MONSOON CIRCULATION AND RAINFALL OVER CHINA

This paper proposes an index of land-sea thermal difference(ILSTD)that describes its zonal andmeridional strength responsible for East Asian monsoon circulation to study its relation to the EastAsian monsoon circulation and the summer rainfall over China on an interannual basis.Results are asfollows:(1)ILSTD can be used to measure the strength of East Asian summer monsoon in such away that the strong(weak)ILSTD years are associated with strong(weak)summer monsooncirculation.(2)The index also reflects well summer rainfall anomaly over the eastern part of China.In the strong index years,rain belt is mainly located over the northern China,and serious droughtemerges in the Jianghuai valleys and mid-lower reaches of the Changjiang River,along with increaseof rainfall in North and South China,but in the weak years it is contrary.(3)Besides,the index hasobvious QBO and quasi 4-year oscillations,but the periods and amplitudes have significant changes onan interdecadal basis.     

高空纬向风准3.5年振荡特征

本文利用1968—1985年NMC客观分析700和200 hPa月平均纬向风，对其准3.5年振荡（SO）作了研究。发现其主要活动于180°—150°W南北太平洋及25°—35°N纬带上。其传播特征为赤道上向东、副热带基本向西而中纬向东；50°—90°E间经向传播不明显，而太平洋上向北。CEOF分析表明，其方差主要集中于第1，2分量。对其演变及与东太平洋赤道海温的SO分量间关系也作了研究。     

第三次中美气候学术研讨会在上海召开

第三次中国-美国气候学术研讨会于1990年8月1—4日在上海举行。来自美国6位气候学家和来自国家气象局气科院、大气物理研究所、地理研究所、北京大学、南京大学、中山大学、南京气象学院、北京气象学院和上海市气象局等18位中国气候学家共聚一堂,报告了24篇学术论文。     

NUMERICAL EXPERIMENT ON THE SEASONAL VARIATION OF GLOBAL OCEAN AND THE EL NINO PROCESS:PARTI:CONTROL EXPERIMENT ON THE SEASONAL VARIATION OF GLOBAL OCEAN

A 6-layer,4°×5° horizontal resolution global ocean model has been designed and improved.After a 100-year in-tegration,an equilibrium state has been reached from the upper to lower layers.By taking the mean state of last l0 mod-el years as climatic state,we analyzed the characteristics of the seasonal variation in our model integration.The resultsshow that the simulated seasonal variation is similar to the observed.So the design of our model is successful.Then,us-ing the simulated climatic state of the seasonal variation as the initial state,and the observed stress and thermal state asthe atmospheric forcing,we simulated the process of El Nino in 1972—1973 successfully.The simulated results of sea-sonal variation using our model will be presented in part I.     

THE ATMOSPHERIC HEAT BUDGET OVER THE WESTERN PART OF THE TIBETAN PLATEAU DURING MONEX, 1979

The atmospheric heat source strength over western Tibet has been computed for the period beginning with the last ten days in May, 1979 and extending through August, 1979. Our results show a significantly smaller heat source than that obtained by other authors. The discrepancy is mainly due to adjustments in the dray, coefficient suggested by observations and numerical modeling experiments. We subdivided western Tibet into northern and southern parts. In the north sensible heating, SH, provides the dominant input into the atmospheric heat source, whereas in the southern part latent heat, LP, offers a significant contribution after the start of the rainy season.Detailed heat budget calculations were also carried out over limited regions of southwestern Tibet which hau good station coverage. During periods with area-averaged rainfall ≤1 mm/day an atmospheric heat source maximum was located over southwestern Tibet near the 500 hPa level, while a heat sink dominated the upper troposphere in a layer of subsi     

评“1960年的Elsasser辐射图与山本辐射图”兼对“几个幅射图解的比较”一文的意见

大气长波辐射的图解法最早由Mugge和Moller(1932)研究。Elsasser(1942)则提出便于使用的Elsasser辐射图解。此后,大量作者提出了许多新的图解,其中比较成功的为山本图解。1960年,Elsasser等根据最新的吸收光谱实验资料重新给出了辐射图解。在山本与Elsasser(1960)的论文中,用了很多篇幅讨论了广义吸收系数随温度的变化,并指出广义吸收系数随温度的变化对大气长波辐射传输起着重要作用。他     

春夏季节转换中西太平洋副热带高压东移与大尺度环流和温度场变化关系

分析了由春向夏的季节转换过程中西太平洋副热带高压与大尺度环流和温度场之间的变化关系.结果表明:4月份,西太平洋副热带高压开始表现出向东移动特征,6月份它与向西移动的北美副高在东太平洋120～160 (W区域合并.这一期间,沿15～20 (N之间的纬圈环流同时表现出向东移动特征,该纬圈环流的上升支位于南海-西太平洋暖池一带,下沉支主要位于东太平洋180 (～120 (W区域.伴随上述变化,位于北半球太平洋的局地Hadley环流在纬向随时间表现出东强西弱变化特点.西太平洋副高向东移动与15～20 (N之间的纬圈环流和130 (W东太平洋局地Hadley环流在15～25 (N上空交汇、下沉密切相关.在由春向夏季节转换中,大气和海表温度关于赤道季节转换速率沿纬向表现出东慢西快差异,上述变化为西太平洋副热带高压的向东移动提供了有利的气候背景.