1991年江淮特大暴雨的降水性质与对流活动   总被引：11，自引：3，他引：11  

陆尔  丁一汇  M. Murakami  K. Takahashi 《气象学报》1997,55(3):318-333

从计算大尺度热源和分析ＴＢＢ资料两个方面，阐述了１９９１年江淮梅雨期间降水性质与对流活动的季节性演变特征。结果表明：梅雨期间江淮上空３个强上升运动时段分别形成了３场暴雨，由暴雨释放的热量使江淮大气出现了３个时段的强加热；３场暴雨的降水性质呈显著的季节性演变，由第１场暴雨以锋面性降水为主发展到第３场暴雨异常强的对流性降水。文中详细分析了热源和水汽汇的时空分布特征，并从大气运动场和热力结构讨论了盛夏强对流降水期间积云对流以涡动形式对热量和水汽的强铅直输送作用。江淮地区ＴＢＢ值能很好地反映降水状况，雨期一致地对应于ＴＢＢ低于２５０Ｋ的时段。梅雨中后期东亚地区对流活动季节性地增强，带状对流区（特别是ＴＢＢ高负距平区）与雨带位置相符。对流带位置及对流活动强弱与西南暖湿气流活动密切相关，它很好地表征了东亚地区的低空急流（给积云输送热带对流大气）。梅雨期间对流带主要出现在江淮流域，但可在东亚范围内飘移，它落在江淮与否则决定了江淮暴雨的维持与中断  相似文献   

中国地区对流参数化加热廓线的分析研究和数值试验          下载免费PDF全文

朱蓉  徐大海 《应用气象学报》1996,7(2):221-228

为了使MM4模式在我国范围内得到很好的应用，需用我国的气候资料对MM4模式中的对流加热参数进行统计分析，以适应我国各地区气候状态。为此，本文选取了1990～1993年6～8月的常规探空资料，采用郭氏的对流参数化方案，放宽假设后直接计算求得各站点各时次的对流加热率参数，再按气象站的站区分区进行统计。结果表明:黄河以南地区，对流云上、下部的垂直加热率比较均匀，加热廓线峰值偏低，为σ=0.65～0.80，对流云顶也比较高。黄河以北地区，对流云中的垂直加热率分布不均，加热集中在某一层上，加热廓线峰值出现在σ=0.  相似文献   

植被冠层湍流代数应力模式     

张运福  储长树 《气象》1996,22(5):39-42

从植被冠层湍流时空平均雷诺应力方程出发，根据植被冠层内有关参数化的准则，建立了湍流代数应力模式，并用玉米和小麦两种作物地的实测资料对模式进行了验证。  相似文献   

EFFECTS OF SPATIAL VARIABILITY ON THE SCALING OF LAND SURFACE PARAMETERIZATIONS   总被引：1，自引：0，他引：1  

ZHENGLIN HU  SHAFIQUL ISLAM 《Boundary-Layer Meteorology》1997,83(3):441-461

Understanding and modelling physical and dynamical processes over heterogeneous land surfaces have becomea central focus of many recent studies. There is aconsiderable debate, however, over how to representthe effects of spatial heterogeneity in mesoscale andglobal scale models. Here, a computationally efficientanalytical approach is presented to evaluate scalingproperties of land surface representations. It isshown that the effects of spatial variability may not benegligible for commonly encountered land surfaces andassociated parameterizations. Second-order correction termsinvolving variances of the parameters and covariancesof each pair of land surface parameters are developedto account for the effects ofheterogeneity. Using this analytical approach, weshow that the detail of spatial heterogeneity may not beimportant for the infrared radiation and reflectedsolar radiation from the surface, while sensible andlatent heat fluxes are shown to be sensitive toheterogeneity. Assumptions related todifferent parameterizations for the same physicalprocess could potentially lead to different inferencesregarding the influence of spatial heterogeneity. Theproposed approach, however, is capable of identifying therole of different parameterizations in estimating theinfluence of spatial heterogeneity. These analyticalresults are consistent with the results of severalrecent numerical and field experiments that deal withthe effects of small-scale heterogeneity in landsurface characteristics.  相似文献   

Nonlinear interactions between gravity waves and tides   总被引：1，自引：0，他引：1  

Liu Xiao  Xu JiYao  Ma RuiPing 《中国科学D辑(英文版)》2007,50(8):1273-1279

In this study, we present the nonlinear interactions between gravity waves (GWs) and tides by using the 2D numerical model for the nonlinear propagation of GWs in the compressible atmosphere. During the propagation in the tidal background, GWs become instable in three regions, that is z = 75―85 km, z = 90―110 km and z = 115―130 km. The vertical wavelength firstly varies gradually from the initial 12 km to 27 km. Then the newly generated longer waves are gradually compressed. The longer and shorter waves occur in the regions where GWs propagate in the reverse and the same direction of the hori-zontal mean wind respectively. In addition, GWs can propagate above the main breaking region (90—110 km). During GWs propagation, not only the mean wind is accelerated, but also the amplitude of tide is amplified. Especially, after GWs become instable, this amplified effect to the tidal amplitude is much obvious.  相似文献   

Sensitivity Study of the South China Sea Summer Monsoon in 1998 to Different Cumulus Parameterization Schemes     

柳艳菊  丁一汇 《大气科学进展》2007,24(3):360-376

In this study, the improved high-resolution regional climate model of the China National Climate Center （RegCM_NCC） is used to examine the sensitivity of the simulated circulation and rainfall during the South China Sea summer monsoon （SCSSM） period during 1998 in an effort to compare to other cumulus param- eterization schemes. The investigation has indicated that the model is capable of simulating the seasonal march of the SCSSM and that the results were very sensitive to the choice of cumulus parameterization schemes. It seems that the Kuo cumulus parameterization scheme simulates the process of the SCSSM onset reasonably well, which can reproduce the onset timing and dramatic changes before and after the onset, especially the upper- and lower-level wind-fields. However, there are still some discrepancies between the simulations and observations. For example, the model can not completely simulate the intensity of the rainfall or the location of the western Pacific subtropical high as well as the feature of the rapid northward propagation of seasonal rain belt.  相似文献   

中尺度模式中各种积云参数化方案的对比试验   总被引：10，自引：2，他引：10  

晏红明  任菊章  段玮 《南京气象学院学报》2006,29(4):491-499

利用非静力中尺度MM5数值模式，选择Anthes-Kuo、Grell、Kain-Fritsch和Betts-Miller4种积云对流参数化方案，对2003年7月25-26日台风登陆减弱为中尺度低压系统后影响云南产生的强降水过程进行模拟试验，重点分析了4种参数化方案模拟的降水分布、降水强度和中尺度低压的流场特征。结果表明：4种积云参数化方案对这次强降水过程均有一定的模拟能力，能够很好地模拟过程强降水中心的位置，但Grell、Kain-Fritsch和Betts-Miller3种方案模拟的大雨范围比实况大雨范围明显偏小，Betts-Miller方案模拟的降水强度比实况偏大，Anthes-Kuo方案的模拟结果与实况比较接近，它不仅能够很好地模拟强降水过程的降水区范围、降水强度和降水中心位置，还能很好地再现低压环流系统的一些中尺度特征。  相似文献   

北京地区夏季边界层结构日变化的高分辨模拟对比   总被引：14，自引：4，他引：14       下载免费PDF全文

陈炯  王建捷 《应用气象学报》2006,17(4):403-411

使用WRF中尺度数值模式, 分别选用两种不同的边界层参数化方案 (MYJ, YSU) 和3种陆面参数化方案 (SLAB, Noah, RUC), 对2004年7月1日08:00—7月4日20:00 (北京时) 北京地区夏季边界层结构进行1 km的高分辨模拟。对比分析了近地面层风场、温度场以及边界层的日变化特征, 结果发现:WRF模式基本模拟出了北京夏季边界层的日变化特征; 在边界层方案中, MYJ方案描述的边界层结构较YSU方案合理; Noah陆面模式较好地反映了城市的热岛效应; 无降水时, 风速及边界层高度对于陆面过程不敏感, 而降水发生后, 陆面过程对于边界层结构的影响增大; 各方案模拟的城区风速明显偏大, 这是因为没有充分考虑城市建筑物的阻力作用。  相似文献   

Multi-year Simulations and Experimental Seasonal Predictions for Rainy Seasons in China by Using a Nested Regional Climate Model （RegCM_NCC）. Part Ⅰ： Sensitivity Study   总被引：21，自引：0，他引：21  

丁一汇  史学丽  刘一鸣  刘艳  李清泉  钱永甫  苗蔓倩  翟国庆  高昆 《大气科学进展》2006,23(3):323-341

A modified version of the NCAR/RegCM2 has been developed at the National Climate Center （NCC）, China Meteorological Administration, through a series of sensitivity experiments and multi-year simulations and hindcasts, with a special emphasis on the adequate choice of physical parameterization schemes suitable for the East Asian monsoon climate. This regional climate model is nested with the NCC/IAP （Institute of Atmospheric Physics） T63 coupled GCM to make an experimental seasonal prediction for China and East Asia. The four-year （2001 to 2004） prediction results are encouraging. This paper is the first part of a two-part paper, and it mainly describes the sensitivity study of the physical process paraxneterization represented in the model. The systematic errors produced by the different physical parameterization schemes such as the land surface processes, convective precipitation, cloud-radiation transfer process, boundary layer process and large-scale terrain features have been identified based on multi-year and extreme flooding event simulations. A number of comparative experiments has shown that the mass flux scheme （MFS） and Betts-Miller scheme （BM） for convective precipitation, the LPMI （land surface process model I） and LPMII （land surface process model Ⅱ） for the land surface process, the CCM3 radiation transfer scheme for cloud-radiation transfer processes, the TKE （turbulent kinetic energy） scheme for the boundary layer processes and the topography treatment schemes for the Tibetan Plateau are suitable for simulations and prediction of the East Asia monsoon climate in rainy seasons. Based on the above sensitivity study, a modified version of the RegCM2 （RegCM_NCC） has been set up for climate simulations and seasonal predictions.  相似文献   

MM5模式中城市冠层参数化方案的设计及其数值试验   总被引：15，自引：5，他引：15  

李晓莉  何金海  毕宝贵  李泽椿  王欣 《气象学报》2003,61(5):526-539

文中在综合国外一些较先进的中尺度模式城市作用参数化方案的基础上 ,从城市下垫面结构对城市边界层大气作用的物理机制及实际应用两方面出发 ,对城市下垫面结构和人为活动等因素对边界层结构的影响及中尺度模式中城市化作用的合理体现等问题进行了较全面的考虑 ,改进和设计出能够较全面、细致地描述城市结构对大气边界层动力、热力结构的影响 ,且适合中尺度模式结构特点的城市冠层参数化方案 (UCP) ,并实现了其与MM5模式的耦合。进行了耦合后的UCP方案及采用原城市作用方案的MM5模式对BECAPEX试验期间北京地区气象条件多重嵌套细尺度进行了模拟试验 ,并与观测结果对比 ,结果表明 :相比于MM 5模式中原有表示城市作用的参数化方案来讲 ,设计的UCP方案在很大程度上提高了MM 5模式对城市边界层热力和动力结构的模拟能力。  相似文献