土壤—植被—大气系统水分散失机理的数值模拟

Numerical Simulation of Evapotranspiration Mechanism over Soil-Vegetation-Atmosphere System

以Deardorff(1978)提出的陆面参数化方案和Noilhan等人(1989)土壤水分参数化方案为基础,对陆面物理过程参数化方案进行了改进,在模式中较详细地考虑了植被和地面的各种物理参量如地面和叶面的反射率和发射率,净叶面面积指数,植被的物理阻抗等,并与大气边界层模式耦合。应用该模式模拟了沙漠及绿洲地区不同植被覆盖率情况下的蒸散量、土壤含水量和表面温度的日变化和连续变化特征;对不同植被覆盖率的热量平衡特征进行了比较。结果表明该模式较好地反映了地表蒸散3阶段的变化趋势特征,揭示出下垫面热量平衡分量间的相互转换过程。该模式可以用于中尺度的气象和区域气候模式,模拟和预测不同植被覆盖情况下近地层的热量输送和水分散失情况。

The model mainly uses the method developed by Deardorff in 1978, accompanied with some improvements made by Noilhan in 1989.A numerical model has been established to simulate the evapotranspiration process of moisture on land-surface with different vegetative cover. It includes lots of physical parameters of ground and foliage, such as albedos and emissivities of ground and foliage, net leaf area index, stomatal resistance and so on. The continuous variation of surface evapotranspiration and surface soil moisture content with different vegetative cover, and mean air humidity and surface temperature in different vegetation canopy were simulated, Diurnal variation of surface evapotranspiration and surface evapotranspiration with different vegetative cover were simulated also. By the way, heat balance have been compared over different vegetation cover. The results are in excellent agreement with others. It has successfully described the features of temperature and moisture during this process and the conversion process between components of heat on land-surface. We also do some experiments of validation at the same time, whose results are in excellent agreement with theory. The results indicate that the model can be used in mesoscale meteorology and region climate to simulate and forecast the process of transport of heat and evapotranspiration of moisture on land-surface with different vegetation cover.