大气凝结水汽汇、凝结潜热作用与积云对流参数化   总被引：2，自引：0，他引：2  

辜旭赞  张兵 《气象学报》2006,64(6):790-795

从引入包含质量(水汽)源、汇的连续方程出发,重新推导出大尺度凝结降水和积云对流凝结降水之水汽汇起作用的热力学方程,从而重新给出气压、气温预报方程及地面气压与高空位势高度预报方程。发现,在此基础上,才能实现凝结3个作用:气块水汽质量流失与气压降低;气块虚温降低;加热气块;和通过大气运动方程,实现大气凝结潜热“热机”作功。这时,对于预报气压、气温场,积云对流参数化方案中的参数在凝结3个作用中保持一致。否则,通过积云对流参数化方案,虽可以近似实现对于预报气压和气温场的凝结3个作用,但不可能调好参数的降水物理特性及其时空分布特征。且对于静力模式预报地面气压和高空位势高度场,不可能实现上述的第一凝结作用。最后表明,当模式分辨率提高到只用降水显式方案、不再用积云对流参数化方案后,则必须引入包含水汽源、汇的连续方程。因在热带海洋面上的水蒸发过程,水汽进入大气将改变地面气压场,且蒸发潜热可分为内潜热(水汽内能)和外潜热(水汽压力能),内潜热立即成为大气热能的一部分,而外潜热直接对大气层作功,使得大气位能增加。文中研究了大气中的大尺度凝结降水和积云对流凝结降水对气压场与位势高度场的影响。一般积云对流参数化方案都已考虑内潜热对大气的加热作用,但还须考虑因凝结与降水造成地面气压场及高空位势高度场的变化,后者应是外潜热作用的结果。在上述研究过程中,必须引入考虑凝结作用的连续方程,且最终可以改变有降水(包括大尺度凝结降水和积云对流凝结降水)发生时的数值预报模式动力框架。  相似文献   

矿产资源管理信息系统设计与开发   总被引：1，自引：0，他引：1  

沈泉飞  顾和和  张海荣  曹敏  钟立喜  房友东 《国土资源信息化》2006,(5):19-22

基于GIS的矿产资源管理信息系统采用地理信息系统(GIS)技术、SQL Server数据库技术以及网络技术,实现了矿产资源信息图形数据与属性数据统一管理,为矿产资源管理工作提供了现代化的科学管理手段和决策支持。本文介绍了系统的设计与实现、系统包含的工作模块、各个模块的功能结构以及采用的技术特点。  相似文献   

Upscaling: Effective Medium Theory, Numerical Methods and the Fractal Dream     

Y. Guéguen  M. Le Ravalec  L. Ricard 《Pure and Applied Geophysics》2006,163(5-6):1175-1192

Upscaling is a major issue regarding mechanical and transport properties of rocks. This paper examines three issues relative to upscaling. The first one is a brief overview of Effective Medium Theory (EMT), which is a key tool to predict average rock properties at a macroscopic scale in the case of a statistically homogeneous medium. EMT is of particular interest in the calculation of elastic properties. As discussed in this paper, EMT can thus provide a possible way to perform upscaling, although it is by no means the only one, and in particular it is irrelevant if the medium does not adhere to statistical homogeneity. This last circumstance is examined in part two of the paper. We focus on the example of constructing a hydrocarbon reservoir model. Such a construction is a required step in the process of making reasonable predictions for oil production. Taking into account rock permeability, lithological units and various structural discontinuities at different scales is part of this construction. The result is that stochastic reservoir models are built that rely on various numerical upscaling methods. These methods are reviewed. They provide techniques which make it possible to deal with upscaling on a general basis. Finally, a last case in which upscaling is trivial is considered in the third part of the paper. This is the fractal case. Fractal models have become popular precisely because they are free of the assumption of statistical homogeneity and yet do not involve numerical methods. It is suggested that using a physical criterion as a means to discriminate whether fractality is a dream or reality would be more satisfactory than relying on a limited data set alone.  相似文献   

Effects of climate change on coastal fresh groundwater resources   总被引：1，自引：0，他引：1  

Priyantha Ranjan  So Kazama  Masaki Sawamoto 《Global Environmental Change》2006,16(4):388-399

This study evaluates the impacts of climate change on fresh groundwater resources specifically salinity intrusion in water resources stressed coastal aquifers. Our assessment used the Hadley Centre climate model, HadCM3 with high and low emission scenarios (SRES A2 and B2) for years 2000–2099. In both scenarios, the annual fresh groundwater resources losses indicate an increasing long-term trend in all stressed areas, except in the northern Africa/Sahara region. We also found that precipitation and temperature individually did not show good correlations with fresh groundwater loss. However, the relationship between the aridity index and fresh groundwater loss exhibited a strong negative correlation. We also discuss the impacts of loss of fresh groundwater resources on socio-economic activities, mainly population growth and per capita fresh groundwater resources.  相似文献   

四川省森林火险预报系统     

吕学东  顾清源  谌贵珣 《高原山地气象研究》2006,26(3)

四川省森林火险预报系统是用VB6.0语言编写,采用多因子线性回归统计方法建立的一套森林火险等级预报业务系统;本系统通用性强、功能齐全,为预报员提供了一套较完备的火险等级预报工具,同时实现了等值线这一科学计算可视化表现方式,摆脱了对专业绘图软件的依赖.  相似文献   

Cirrus cloud horizontal and vertical inhomogeneity effects in a GCM     

Yu Gu  K. N. Liou 《Meteorology and Atmospheric Physics》2006,91(1-4):223-235

Summary A set of the inhomogeneity factor for high-level clouds derived from the ISCCP D1 dataset averaged over a five-year period has been incorporated in the UCLA atmospheric GCM to investigate the effect of cirrus cloud inhomogeneity on climate simulation. The inclusion of this inhomogeneous factor improves the global mean planetary albedo by about 4% simulated from the model. It also produces changes in solar fluxes and OLRs associated with changes in cloud fields, revealing that the cloud inhomogeneity not only affects cloud albedo directly, but also modifies cloud and radiation fields. The corresponding difference in the geographic distribution of precipitation is as large as 7 mm day⁻¹. Using the climatology cloud inhomogeneity factor also produces a warmer troposphere related to changes in the cloudiness and the corresponding radiative heating, which, to some extent, corrects the cold bias in the UCLA AGCM. The region around 14 km, however, is cooler associated with increase in the reflected solar flux that leads to a warmer region above. An interactive parameterization for mean effective ice crystal size based on ice water content and temperature has also been developed and incorporated in the UCLA AGCM. The inclusion of the new parameterization produces substantial differences in the zonal mean temperature and the geographic distribution of precipitation, radiative fluxes, and cloud cover with respect to the control run. The vertical distribution of ice crystal size appears to be an important factor controlling the radiative heating rate and the consequence of circulation patterns, and hence must be included in the cloud-radiation parameterization in climate models to account for realistic cloud processes in the atmosphere.  相似文献   

"2007.4.1"四川盆地强寒潮天气过程分析     

周春花  顾清源  张驹 《高原山地气象研究》2007,27(3)

利用T213 1°×1°和欧洲中心实时资料,对2007年4月l～3日四川盆地区域性寒潮天气过程的环流背景及影响系统进行了分析,结果表明:500 hPa乌拉尔山到贝加尔湖以东为宽广深厚的低压带,地面上巴湖附近为冷高压,此冷高压在500 hPa脊前西北气流的引导下东移南压,是造成此次寒潮大风天气的主要原因;而且低空急流也对降温有一定的作用.  相似文献   

测量不确定度的验证方法     

古成昕  王立民 《高原山地气象研究》2007,27(3)

本文介绍了测量不确定度的验证方法,并举例说明.  相似文献   

Zircon LA-ICP-MS U-Pb dating and Sr-Nd isotope study of the Guposhan granite complex, Guangxi, China     

GU Shengyan HUA Renmin QI Huawen 《中国地球化学学报》2007,26(3):290-300

Zircon U-Pb dating by the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite complex, among which the East Guposhan unit is 160.8±1.6 Ma, the West Guposhan unit is 165.0±1.9 Ma, and the Lisong unit is 163.0±1.3 Ma in age. Much similarity in ages of the three units has thus proved that the whole Guposhan granite complex was formed in the same period of time. They were the products of large-scale granitic magmatism through crust-remelting in the first stage of the Middle Yanshanian in South China. However, the three units have differences both in petrology and in geochemistry. Besides the differences in major, trace and rare-earth elements, they are distinct in their Rb-Sr and Sm-Nd isotopic compositions. The East Guposhan unit and Lisong unit and its enclaves have a similar (87Sr/86Sr)i value of 0.7064 with an average of εNd(t)=-3.03, indicating that more mantle material was evolved in the magma derivation; whereas the West Guposhan unit has a higher (87Sr/86Sr)i value of 0.7173 but a lower εNd(t) value of -5.00, and is characterized by strong negative Eu anomalies and higher Rb/Sr ratios, suggesting that its source materials were composed of relatively old crust components and new mantle-derived components. In addition, an inherited zircon grain in the East Guposhan unit (GP-1) yielded a 206Pb/238U age of 806.4 Ma, which is similar to the ages of the Jiulin cordierite granite in northern Jiangxi and of the Yinqiao migmatic granite in Guangxi in the HZH granite zone. All this may provide new evidence for Late Proterozoic magmatism in the HZH granite zone.  相似文献   

“2007.4.1”四川盆地强寒潮天气过程分析   总被引：1，自引：0，他引：1  

周春花  顾清源张驹 《四川气象》2007,27(3):9-11

利用T2131°×1°和欧洲中心实时资料,对2007年4月1～3日四川盆地区域性寒潮天气过程的环流背景及影响系统进行了分析,结果表明:500hPa乌拉尔山到贝加尔湖以东为宽广深厚的低压带,地面上巴湖附近为冷高压,此冷高压在500hPa脊前西北气流的引导下东移南压,是造成此次寒潮大风天气的主要原因;而且低空急流也对降温有一定的作用。  相似文献