中国关于积云参数化方案的应用   总被引：9，自引：3，他引：6  

刘一鸣 《气象学报》1998,56(2):247-255

文中简要评述并比较了４类积云参数化方案,着重总结了各种积云参数化方案在中国的应用,最后结合中国特点讨论了积云参数化方案在应用中存在的一些问题和改进途径。  相似文献   

The sensitivity of numerical simulation of the east asian monsoon to different cumulus parameterization schemes     

Cheng Anning  Chen Wen  Huang Ronghui 《大气科学进展》1998,15(2):204-220

In this paper, a 5-level spectral AGCM is used to examine the sensitivity of simulated East Asian summer monsoon circulation and rainfall to cumulus parameterization schemes. From the simulated results of East Asian monsoon circulations and rainfalls during the summers of 1987 and 1995, it is shown that the Kuo’s convective parameterization scheme is more suitable for the numerical simulation of East Asian summer monsoon rainfall and circulation. This may be due to that the cumulus in the rainfall system is not strong in the East Asian monsoon region. This paper is supported by the National Key Progranmme “96-908”.  相似文献   

卫星对地观测中大气与地表辐射贡献的参数化   总被引：4，自引：3，他引：1  

吕达仁  段民征 《大气科学》1998,22(4):638-648

卫星对地观测定量遥感地表与大气特性是当前地球科学与应用研究的关键手段之一。在定量遥感中区分大气和地表在地-气系统对空间散射辐射中各自的贡献与作用是关键的一步。这一问题的核心是基于辐射传输方程的数值计算建立起适合应用于遥感反演中分离大气与地表贡献的参数化表达式。本文对特定的气溶胶气候类型和可见/近红外波段建立起定量的表达形式,并对表达式的物理含义和拟合精度进行了分析。最后讨论了其应用的可行性和进一步的工作。  相似文献   

Optimized Computation of Transfer Coefficients in Surface Layer with Different Momentum and Heat Roughness Lengths     

Emmanuel Guilloteau 《Boundary-Layer Meteorology》1998,87(1):147-160

A new method for computing the surface transfer coefficients is proposed, based on state-of-the-art empirical flux-profile relationships. The influence of the roughness length ratio is first demonstrated with the classical iterative calculation method. Then a non-iterative algorithm is developed, taking into account the difference between momentum and heat roughness lengths.The new method is validated by comparison with the reference iterative computation. The large gain-in computer processing time (CPU) time gain for the calculation of surface fluxes in Eulerian grid models is finally assessed.  相似文献   

ENTROPY THEORY AND PARAMETERIZATION OF NONUNIFORM DISTRIBUTION OF PRECIPITATION     

Zhang Zhengqiu  Li Weiliang 《Acta Meteorologica Sinica》1998,12(3):334-344

In this paper a parameterization of nonuniform distribution of precipitation has been madefrom the aspect of the maximum entropy theory.Results from theory and observation show that,the density function of precipitation depth on the subgrid scale over the grid area of a climate modelis the function of the gamma distribution.On this basis,the relative coverage of snow in the regionoccupied by vegetation in the grid area of a model is parameterized.Meanwhile the calculatedresults from the parameterizations are also compared with those from the empirical formulas bysome other meteorologists.Results show that it is feasible to parameterize the nonuniformdistribution of precipitation over the grid area at the angle of entropy theory.  相似文献   

Impact of Atmospheric Surface-layer Parameterizations in the new Land-surface Scheme of the NCEP Mesoscale Eta Model   总被引：5，自引：1，他引：5  

Fei Chen  Zavisă Janjić  Kenneth Mitchell 《Boundary-Layer Meteorology》1997,85(3):391-421

We tested three atmospheric surface-layer parameterization schemes (Mellor-Yamadalevel 2, Paulson, and modified Louis), both ina 1-D mode in the new NCEP land-surface scheme against long-term FIFE and HAPEX observations, and in a coupled 3-D mode withthe NCEP mesoscale Eta model. The differences inthese three schemes and the resulting surface exchange coefficients do not, in general, lead to significant differences in model simulated surface fluxes, skin temperature, andprecipitation, provided the same treatment of roughness length for heat is employed.Rather, the model is more sensitive to the choice of the roughness length for heat. To assess the latter, we also tested two approaches to specifythe roughness length for heat: 1) assuming the roughness length for heat is a fixed ratio of the roughness length for momentum, and 2) relating this ratio to the roughness Reynolds number as proposed by Zilitinkevich.Our 1-D column model sensitivity tests suggested that the Zilitinkevich approach can improve the surface heat fluxand skin temperature simulations. A long-term test with the NCEP mesoscaleEta model indicated that this approach can also reduce forecast precipitation bias. Based on these simulations, in January 1996 we operationally implemented the Paulsonscheme with the new land-surface scheme of the NCEP Eta model, along with the Zilitinkevich formulation to specify the roughness length for heat.  相似文献   

郭型积云对流参数化方案的对比试验及潜热加热效应   总被引：1，自引：3，他引：1  

钱正安  何驰 《高原气象》1989,8(3):217-227

本文利用复杂地形条件下的嵌套细网格预报模式和1979年FGGEⅢ_b级资料对郭型积云对流参数化方案中的垂直加热分布函数及增湿系数进行了对比试验,並讨论了潜热加热效应。 结果表明,在四种垂直加热分布函数中,θ_(se)差方案主要加热出现在对流层高层,这使气柱渐趋稳定,最后抑制积云对流发展,预报效果较好。在三种增湿系数方案中,以分段线性函数法为好,它计算的b值分布合理,预报效果也好。因水汽凝结潜热加热将使气柱平均温度升高,上升运动加强,对流层中低层降压辐合,使对流层高层加压辐散。  相似文献   

中尺度模式云降水物理方案介绍   总被引：13，自引：6，他引：13       下载免费PDF全文

楼小凤胡志晋  王鹏云周秀骥 《应用气象学报》2003,14(Z1):49-59

介绍大气模式中湿过程的饱和凝结、对流参数化和显式云物理三种方法的适用条件和特点.中尺度大气模式的对流参数化和显式过程一般有多种方案,介绍了多种方案的主要处理方法、基本微物理过程、预报量和主要特点.对流云模式都采用显式过程,但不同模式的湿过程有一定的差别,有各自的微物理特点,对有代表性的云物理方案进行了叙述和分析.  相似文献   

TRMM/PR资料在中尺度模式MM5中的应用     

徐枝芳  葛文忠  党人庆  Toshio IGUCHI  Takao TAKADA 《大气科学进展》2003,20(2):185-193

将中尺度非静力模式MM5中的积云参数化Grell方案作了改进，使它含有降水云的云水，即雨水含量，并用该模式对1998年6月29日08时-30日08时(北京时)和1998年7月1日08时-2日08时(北京时)发生在淮河流域的两次特大暴雨进行数值模拟研究，同时通过采用R-qr关系将TRMM／PR(Tropical Rainfall Measuring Mission/Precipitation Radar)得到的降水强度资料月计算出比含水量qr，然后用qv′＝qv qr取代原模式中的比湿qv。结果表明将TRMM／PR资料加入模式后，由于PR雷达具有较高的空间分辨率，能够很好地反映中小尺度系统的空间结构，能够使湿度值接近实际，缩短了中尺度系统的发展时间，使得模拟出来的降雨强度、雨量中心位置以及雨带形状更接近实况。  相似文献   

共聚焦点道集偏移速度建模   总被引：3，自引：1，他引：3  

李振春  穆志平  张建磊  张凯  王延光  陈世军 《物探与化探》2003,27(5):403-406,410

偏移速度建模可在多种道集实现.基于等时原理和差异时移分析,提出了共聚焦点道集偏移速度建模方法.偏移速度的更新是利用约束参数迭代反演实现,模型的参数化主要依据实际情况而定.为适应横向变速,选用了垂直速度梯度参数.模型试算表明:偏移速度相对误差在0.25%范围内,反射层深度误差小于10m.  相似文献