沙漠绿洲非均匀分布引起的中尺度通量的数值模拟  

Numerical Simulations on Mesoscale Fluxes Generated by Desert and Oasis Heterogeneous Distributions

作　　者：牛国跃[1] 洪钟祥[1] 孙菽芬[1] 

机构地区：[1]中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室

出　　处：《大气科学》1997年第4期385-395,共11页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金;青藏高原地气系统物理过程观测和理论研究(攀登B)项目

摘　　要：为了研究大气环流模式次网格中尺度通量的参数化问题，本文发展了一个Ｐｉｅｌｋｅ中尺度边界层与陆面过程的耦合模式，陆面过程模式中包括一个简单植被水热传输模式及一个裸土沙漠模式。利用这一耦合模式，对黑河试验区中沙漠和绿洲这种典型的非均匀下垫面进行了模拟，２０多个数值试验的模拟结果表明：（１）中尺度通量在特定的情况下具有和湍流通量相当的重要性，因此，大尺度模式中对中尺度通量的参数化是十分必要的。（２）对于中尺度通量的发展存在一个明显的最优尺度和最优块数，即当绿洲尺度为６０ｋｍ，３块时，中尺度通量最大。而且当块数增加到一定数目时，可以忽略非均匀效应。（３）背景风速的增大可以使中尺度通量减小；In order to study mesoscale water and heat fluxes induced by heterogeneous landscape in GCMs grid scale, the Pielke model has been coupled with a combined land surface processes model which includes a simplified canopy model and a simplified desert soil model. With this copuled model numerical simulations have been carried out on the typical heterogeneous land surface: oasis and desert which is distributed in the HEIFE experiment area. The results indicate that: (1) The mesoscale fluxes of water and heat are comparable to turbulence fluxes. Therefore,it is necessary to parameterize the mesoscale fluxes in large scale numerical model. (2) There is an optimal patch scale and patch number formesocale fluxes,i.e.,when oasis scale is 60 km and patch number is 3 patches, the mesoscale fluxes are the biggest. The mesoscale fluxes can be neglected when the patch number becomes large. (3) The increase of background wind speed decreases the mesoscale fluxes decrease; The roughness experiments indicate that the decrease of thermal difference between oasis and desert makes the mesoscale fluxes decrease.

关 键 词：大气环流 沙漠绿洲 中尺度通量 数值模拟 

分 类 号：P434.5[天文地球—大气科学及气象学] P435