绿洲区域气候效应的数值模拟

在改进的土壤植被大气模式(MSPAS)的基础上,引入一个有效的大气辐射传输方案,建立了一个能在物理上真实地描述陆气相互作用及其反馈机制的二维模式(MLAIM).利用HEIFE实验的观测资料,对改进了土壤水分传输、近地面层湍流输送以及植被物理过程参数化方案后的MLAIM进行了检验.结果表明,MLAIM能够合理地模拟陆气相互作用中的各种物理过程,能够有效地模拟绿洲与沙漠的地表能量收支情况.因此利用MLAIM对绿洲的气候效应进行了研究,分析了绿洲"冷岛效应"与"湿岛效应"的形成机理,并且着重研究了绿洲对其周围沙漠的影响.结果表明,绿洲对沙漠的水汽输送是影响沙漠地表能量收支以及绿洲周边区域气候的最重要的因子.

A Numerical Simulation Study on Regional Climate Effect over Oasis Area

By extending Modified Soil-Plant-Atmosphere Scheme(MSPAS) to include an effective parameterization scheme of atmospheric radiation transfer,a two-dimensional model was built,which allows physically realistic simulation of modified land atmosphere interactions model(MLAIM) and relevant feedback mechanisms.After modification of parameterization schemes of soil water transfer,atmospheric surface layer turbulence transfer,and vegetation processes,the simulation results were validated by using observational data in HEIFE experiment.Results indicate that the modified MLAIM can simulate well physical processes in land atmosphere interactions.As a result,MLAIM can be used as an effective method to simulate land surface energy budget in oasis and desert,and to study the regional climate effect of oasis.The authors discussed the causes of oasis "cold island effect" and "wet island effect",and focused on oasis's influence on its surrounding desert.Results indicate that the water vapor transport from oasis to desert serves as the most important factor which affects the land surface energy budget in desert as well as the regional climate in oasis's surrounding areas.