用全球大气混合层海洋环流模式模拟二氧化碳增加对土壤湿度季节变化的影响

本文利用全球三维大气耦合混合层海洋环流模式模拟大气中二氧化碳浓度增加对土壤湿度的影响。敏感试验(2×CO_2)与控制试验(1×CO_2)对照表明,当大气中二氧化碳浓度增加时,全球土壤湿度在各季发生明显变化。其中两半球低纬度地区在冬季土壤温度变温,两半球中纬度地区则在各季土壤湿度变干,北半球高纬度地区土壤湿度在夏季变干,其余各季变温。分析大气中二氧化碳浓度增加造成土壤温度全球变化的可能物理机制表明,地面水循环和热量循环是重要的因素。     

INFLUENCE OF SOIL MOISTURE AND VEGETATION ON CLIMATE CHANGES INDUCED BY THERMAL FORCING

A land-process scheme has been incorporated in a vertical one-dimensional time-dependent atmospheric modeland numerical experiments have been performed with the coupled model to examine influences of soil wetness and vege-tation on climate changes associated to thermal forcing.It is showed that response of land-surface temperature to thethermal forcing becomes small with increase of soil water content and vegetation cover.Furthermore,the response ismore obvious in arid climate region than in humid one.The result also shows that there exist two patterns of corre-sponding relation between variations in air temperature and humidity on the land surface in response to hydrologic andthermal focing.     

INFLUENCE OF SOIL MOISTURE AND VEGETATION ON CLIMATE CHANGES INDUCED BY THERMAL FORCING*

A land-process scheme has been incorporated in a vertical one-dimensional time-dependent atmospheric model and numerical experiments have been performed with the coupled model to examine influences of soil wetness and vegetation on climate changes associated to thermal forcing.It is showed that response of land-surface temperature to the thermal forcing becomes small with increase of soil water content and vegetation cover.Furthermore,the response is more obvious in arid climate region than in humid one.The result also shows that there exist two patterns of corresponding relation between variations in air temperature and humidity on the land surface in response to hydrologic and thermal focing.     

北极多冰年和少冰年的大气环流差异

本文利用一个改进的海冰热力模式,取北极区大气和有关场的气候资料,模拟了1982年10月至1988年9月的北极海冰空间分布和季节变化的循环特征,较好地模拟出多冰年（1983,1987）和少冰年（1984,1986）。模拟结果与部分研究工作以及实况相比较,基本状况趋于一致。并且在此基础上进一步探讨了北极多冰年和少冰年的大气环境差异,可以看到多冰年的北极极涡偏西半球;少冰年的北极极涡基本是围绕极地。从而进一步影响多冰年和少冰年大气环流差异,特别是对亚洲环流的影响较大。     

EXPERIMENTS OF A REDUCED GRID IN LASG/IAPWORLD OCEAN GENERAL CIRCULATION MODELS (OGCMs)

Due to the decrease in grid size associated with the convergence of meridians toward the poles in spherical coordinates, the time steps in many global climate models with finite-difference method are restricted to be unpleasantly small. To overcome the problem, a reduced grid is introduced to LASG/IAP world ocean general circulation models. The reduced grid is implemented successfully in the coarser resolutions version model L30T63 at first. Then, it is carried out in the improved version model LICOM with finer resolutions. In the experiment with model L30T63, under time step unchanged though, execution time per single model run is shortened significantly owing to the decrease of grid number and filtering execution in high latitudes. Results from additional experiments with L30T63 show that the time step of integration can be quadrupled at most in reduced grid with refinement ratio 3. In the experiment with model LICOM and with the model’s original time step unchanged, the model covered area is extended to the whole globe from its original case with the grid point of North Pole considered as an isolated island and the results of experiment are shown to be acceptable.     

EXPERIMENTS OF A REDUCED GRID IN LASG/IAP WORLD OCEAN GENERAL CIRCULATION MODELS (OGCMs)

1 INTRODUCTIONIn global climate models belonging to the finitedifference calculation category, the equations aregenerally solved in normal spherical coordinates. Due tothe convergence of meridians towards the poles inspherical coordinates, the combination of thiscoordinate system and explicit finite-difference methodsleads to two problems. First, the pole itself is a point ofsingularity with direction undefined. Second, due to thedependence of the stability from finite-differencenumerics …     

A NUMERICAL SIMULATION OF THE EFFECT OF GLOBAL SSTA ON THE LOW-LEVEL ATMOSPHERIC CIRCULATION AND PRECIPITATION ANOMALIES

By the numerical simulation,the sea surface temperature anomaly(SSTA)of the Pacific andIndian Oceans.being introduced into IAP AGCM,the observed anomalous circulationcharacteristics on the monthly mean 850 hPa have been confirmed:during an El Nino episode thereappears anomalous westerly flow in the low-level atmosphere over the low-latitude Pacific and theanomalous equatorward air flow over the Southeast Asia coast:during a La Nina episode thereappears anomalous easterly flow in the low-level atmosphere over the low-latitude Pacific and theanomalous off-equator air flow over the Southeast Asia coast.If we introduce only Pacific SSTAinto or take off orographic forcing from the model,the simulated anomalous air flow in the low-level atmosphere over the low latitudes will be different.The precipitation departure in conformitywith the observation over the low latitudes has been simulated with this model as well.     

一个统计低云方案及其在大气环流模式中应用初探

文中利用湍流耗散特征时间尺度和湍流垂直扩散系数对湍流二阶距进行参数化 ,将一个统计云方案与一阶湍流闭合方案进行耦合。基于数值试验 ,在不同的相对湿度、温度垂直梯度、以及湍流耗散特征时间尺度条件下 ,对该方案云量模拟能力的分析 ,发现该统计云方案对其采用的参数及湍流耗散特征时间尺度敏感。基于该数值模拟分析 ,修改了该统计云方案 ,并结合其他边界层积云参数化方案 ,给出了一个基于统计的低云参数化方案。将其初步应用于NCARCCM 3后发现 :该方案可以显著增强CCM 3对副热带低云的模拟能力 ,可以合理地模拟出大洋东部大陆西岸冷海域低云量大值中心 ,显示出该方案对于改进大气环流模式低云参数化具有潜在的应用前景。     

对流层中层动能的全球性季节过渡与季节性急变

本文利用１９８０—１９８８年ＥＣＭＷＦ全球资料，计算了５００ｈＰａ各纬度带上的纬向平均动能（Ｋｚ）、涡动动能（ＫＥ）及波数域动能（Ｋｎ，ｎ＝１，２，３，…，１０）。以此考察了南、北半球动能季节过渡的差异，并用Ｔ检验方法讨论了南、北半球以及全球各动能模态的季节性急变现象。现在工作单位：     

IAP GCM模式大气背景环流在厄尔尼诺年的异常

本文分析了中国科学院大气物理研究所大气环流模式(IAP GCM)模式大气5～9月平均环流(本文称为背景环流)。结果表明;厄尔尼诺年一系列重要系统(南方涛动、瓦克环流、哈德莱环流、西太平洋副热带高压和热带辐合带)及大范围降水均发生明显异常;北半球西太平洋热带、副热带是环流异常的主要区域。它们与观测资料的分析结果基本一致,从而论证了该模式在低纬环流研究中的应用前景。     

OBSERVING RESULTS OF THE ATMOSPHERIC MIXED LAYER IN BEIJING AREA AND THE EVALUATION OF THEORETICAL MODELS

In the present study the data of wind and temperature profiles and sensible heat flux observed in Beijing inJuly and December of 1986,together with the results of water tank experiments for comparison,are used to testthe prediction models of the atmospheric mixed layer with zero order and first order assumption,respectively.The results show that the entrainment rates in summer and winter used in the zero order model are 0.15 and0.10,respectively,while its value in the first order model ranges between 0.15 and 0.19 with a lower rateat the initial stage of mixed layer development.Emphasis in the study is also placed on the relationship between the entrainmert rate and the developmentof the mixed layer.     

70年代末大气环流及中国旱涝分布的突变

使用小波分析方法检测了副高脊线位置在１９７９年发生的突变,检验结果与Ｍ－Ｋ方法检验结果一致,进一步分析指出,东亚乃至全球大气环流在１９７９年也发生了突变,相应地中国降水分布也从中间旱,南北涝转变成中间涝,南北旱的分布,旱涝分布型同时发生突变。     

冷暖事件对大气能量循环和纬向平均环流影响的模拟研究

利用中国科学院大气物理研究所大气科学与地球流体力学数值模拟国家重点实验室新发展的GOALS 5全球海 陆 气耦合模式研究了暖事件 (ElNi no)和冷事件 (LaNina)对大气能量循环和纬向平均环流的影响 ,并用观测资料进行了对比分析。结果表明 :对于纬向平均资料来说 ,冷、暖事件在热带和副热带地区的大气环流相关量的反相变化特征非常清晰 ,中高纬度地区并不明显。此外 ,还发现 ,暖事件时定常涡动的经向热通量的变化是北半球对流层热带外地区温度异常的主要原因 ,而瞬变波的影响则起抵消作用。冷事件时定常波和瞬变波相互抵消的局地特征也依然存在 ,但瞬变波的影响有所增强。     

THE IMPACT OF PRECEDING ATMOSPHERIC CIRCULATION AND SST VARIATION ON FLOOD SEASON RAINFALL IN YUNNAN

Spatial and temporal distribution characteristics and scale range of two significant areas were obtained by analyzing the relationship among summer rainfall in Yunnan province, height field and SST field (40°S – 40°N, 30 °E – 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa for Jan. to May and correlation, and field wave structure. Remote key regions among summer rainfall in Yunnan province, height field and SST field (40°S – 40°N, 30°E – 70°W) across the North Hemisphere at 200 hPa, 500 hPa and 850 hPa were studied through further analyzing of the circulation system and its climate / weather significance. The result shows that the forecast has dependable physical basis when height and SST fields were viewed as predictors and physical models of impacts on rainy season precipitation in Yunnan are preliminarily concluded.     

长波辐射对大气变化的敏感性和在WRF模式中的应用检验

用RRTM长波辐射 (LWR)参数化方案测试了LWR对大气变化的敏感性。结果表明 :高云对向外长波辐射(OLR)、30 0和 5 0 0hPa净LWR通量的减弱作用较中、低云大 ;低云对 85 0hPa和地表净LWR通量的减弱作用较中、高云大。在云层中 ,LWR冷却率受云影响最大 ;在云层下方 ,云对LWR的影响迅速减小 ;而在云层上方 ,冷却率几乎不受云的影响。当水汽含量减少或增加时 ,地表向下LWR受到相应减弱或增强 ,而净LWR则在一定程度上受到相应增强或减弱 ,并且越接近地面 ,受到水汽变化的影响就越大。O3 对LWR的影响相对云和水汽来说是比较小的。文中介绍了在WRF模式中应用RRTM方案预报LWR不同季节的 2个个例 ,给出了应用NCEP/AVN分析资料预报和验证中国范围 2d之内LWR通量的模拟结果。试验表明 ,OLR和 5 0 0hPa净LWR通量与高度形势场有较好的对应关系 ,而地表净LWR很大程度上还受到地形的影响。     

基于LASG/IAP大气环流谱模式的气候系统模式

文章扼要介绍了基于LASG/IAP大气环流谱模式(SAMIL)的气候系统模式的新版本FGOALS-s的发展和结构。出于发展一个在东亚季风模拟方面有一定优势的气候系统模式之目的,FGOALS-s的大气模式分量SAMIL采用了较高的水平分辨率R42,这相当于2.8125°(经度)×1.66°(纬度),高于三角截断T42的分辨率。对FGOALS-s在模拟大气、陆面、海洋和海冰的气候平均态,以及主要的年际变率信号方面的能力进行了检验。分析表明,FGOALS-s成功地控制了气候漂移趋势,能够较为真实地模拟大气、海洋和陆面的气候平均态,特别是受益于大气模式的较高分辨率,由中国西南向东北延伸的夏季风雨带的分布,在模式中得到较为真实的再现,表明该模式在东亚夏季风的模拟上具有较强能力。耦合模式能够成功再现El Ni~no事件的非规则周期变化,但是其年际变化的振幅较之观测要弱。赤道中西太平洋年际变率的强度较之赤道中东太平洋要强。在中高纬度,模式模拟的北大西洋涛动模态,在空间分布上与观测接近。FGOALS-s模式存在的主要问题,是模拟的热带海温偏冷、而中纬度海温则偏暖,原因是模式模拟的云量分布存在偏差,它直接影响到海表的净热通量收支。模式模拟的北大西洋高纬度地区的海温明显偏冷,令该地区的年平均海冰分布的范围明显偏大;然而受南极周边海温偏高影响,南极洲周围的海冰范围则偏少。FGOALS-s的未来工作重点,宜放在大气模式的云过程、海洋模式的经向能量输送过程、以及海洋与大气的淡水通量耦合方案的改进方面。     

珠江三角洲大气边界层概念模型的建立及其应用

根据珠江三角洲地理环境、气候背景和边界层气象观测特征的分析,建立了反映珠江三角洲大气边界层一般机理的珠江三角洲大气边界层概念模型,可解释珠江三角洲地区环境空气质量变化的原因。本概念模型有助于开展珠江三角洲地区大气扩散能力的分析与气流停滞区或灰霾天气的预测预报。     

ATMOSPHERIC BOUNDARY LAYER CONCEPT MODEL OF THE PEARL RIVER DELTA AND ITS APPLICATION

Based on the geographical circumstance, climate and the boundary layer meteorology features of the Pearl River Delta, a boundary layer concept model of the Pearl River Delta was built. The concept model consists of four fundamental factors that affect the boundary layer meteorology of the Pearl River Delta and can convincingly explain the reason of the air quality change in the Pearl River Delta. The model can be used to the diffusion capability analysis, the air pollution potential forecasting or haze forecasting, etc.