土壤-植被-大气系统水分能量传输模拟和验证

MODELING AND VALIDATING WATER AND ENERGY TRANSFER IN SOIL VEGETATION ATMOSPHERE SYSTEM

中文关键词:  土壤－植被－大气系统  地下水  饱和－非饱和土壤  蒸散  敏感性分析

英文关键词:Soil-vegetation-atmosphere system  Underground water  Saturated-unsaturated soil  Evapot ranspiration  Sensitivity analysis

中文摘要:

      本文建立了包括地下水的土壤-植被-大气系统水分能量传输综合模型,并对模型中冠层动量湍流交换反梯度传输现象的描述进行了改进。在此基础上,依据冠层内动量和热量的交换以及辐射传输过程,同时求解地表、冠层能量平衡方程,进而模拟饱和-非饱和土壤的水热传输。用浅地下水地区冬小麦田间试验资料对模型进行验证,结果表明,系统能量平衡各分量和土壤含水量的模拟与观测结果相当一致。模型敏感性分析发现,叶面积指数对总蒸散量的影响随叶面积指数的增加而逐渐减弱;叶片最小气孔阻力对总蒸散量的影响,在该阻力较小时更显着;地下水位对蒸散量的影响在它小于1.5m时不显着,而在1.5～1.75m之间时,蒸散减小较快,主要由于土壤蒸发减小显着,冠层蒸腾稍有增加。

英文摘要:

      A one-dimensional soil-vegetation-atmosphere transfer model including groundwater (GSVAT) is constructed. The model consists of two parts, i. e. soil surface-canopy-atmosphere submodel and sat urated-unsaturated soil submodel. A winter wheat field experimentis conducted to validate the model. Surface energy balance, soil moisture budget and other micromet eorological measurements are measured through jointing to mature period, of 1992 in North China Plain. The simulation of energy balance and soil moisture agree well with the observed. The sensitivity analysis show that the influence of leaf area index (L AI) to evapot ranspiration(ET) is obvious, however it is becoming indisting uishable with a higher LAI; While the minimum stomatal resistance is smaller, it is more sensitive to ET; The response of ET to groundwater table is apparent while water table is between 1.5～1.75 m depth. When the water table is less than 1.5 m, ET decreases due to less intensity of soil evaporation, whereas canopy transpiration is a little bit enhance.