黑河流域山前绿洲灌溉农田蒸散发模拟研究

基于Penman-Monteith蒸散公式, 应用土壤-植被-大气系统水分和能量传输理论对Shuttleworth-Wallace蒸散模型的参数进行改进, 得出解析计算农田作物蒸腾和土壤蒸发的双源模型. 对黑河流域山前绿洲农田春小麦生长期土壤蒸发、作物蒸腾以及总蒸散过程进行了模拟研究. 对模型的计算结果以田间观测和水量平衡方法进行验证, 误差目标NSE=0.98, 说明该模型用于农田蒸发和蒸腾的计算是合理的. 对影响蒸发和蒸腾的主导因子净辐射、叶面积指数、土壤含水量进行了相关性分析, 得出三者的变化对土壤蒸发、作物蒸腾的影响. 通过不同时期日蒸散发量变化特征的分析, 表明土壤、冠层两个界面对能量和水汽传输的交互影响效应显著.

Simulation of the Evapotranspiration from Irrigational Farmlands in the Oases of the Heihe River Basin

Based on Penman-Monteith Equation, the parameters of Shuttleworth-Wallace Model used to calculate the evaporation from sparse crops is modified, a combination equation is derived to calculate the plant transpiration and soil evaporation of agriculture field, and then an one-dimensional soil-vegetation-atmosphere transfer model is employed to simulate the process of soil evaporation, plant transpiration and the total evapotranspiration from irrigational farmlands in the oases in front of the mountains in the Hei River basin during the growing seasons of spring wheat. The modeling relies on the field experiments carried out in the well-irrigated spring wheat lands, and the simulation of evapotranspiration is tested in good fitness with the calculated results from the observation by water balance method. Meanwhile, a sensitivity analysis is also carried out on the net radiation, leaf area index (LAI) and soil water content, to obtain how is their influence to evaporation. Furthermore, the diurnal variation of soil evaporation and crop transpiration shows that two interfaces interact with each other on energy and vapor transition.