中文摘要：

在分析半干旱沙地—草甸区的水面蒸发过程及其影响因子的基础上,采用多元逐步回归分析方法,对水面蒸发的众多影响因子进行逐步筛选,找出显著影响因子,建立水面蒸发与其显著影响因子间的多元非线性回归模型,并模拟计算了彭曼蒸发公式、道尔顿水汽运输理论蒸发公式中的风函数,比较分析了彭曼模型、变异道尔顿模型、多元非线性回归模型计算的水面蒸发量。结果表明：彭曼模型、变异道尔顿模型和最终建立的多元非线性逐步回归模型所得结果十分接近,与实测水面蒸发量的趋势也很一致;除变异道尔顿模型稳定性稍差外,其余两者都具有较好的稳定性;多元非线性逐步回归方法可以找到水面蒸发的显著影响因子,剔除掉不显著影响因子,避免因子相关造成的影响,使所建回归模型具有良好的拟合效果,其决定系数达到了0.773,预测结果令人满意。

英文摘要：

The southern Horqin sandy land,about 70 km away from Tongliao City,Inner Mongolia,China,is a typical sandy land in North China with limited water resources and fragile ecosystems. Quantification of evaporation from water surfaces over this region is critical to developing an understanding of eco-hydrological processes and therefore could be helpful to ecological restoration and water resources management over the arid region. In this study,processes and factors of water surface evaporation in the sand-oasis ecotone of the semiarid region were analyzed using data collected at the Agula Eco-hydrological Experimental Station. Then the stepwise multivariate regression analysis was applied to identify meteorological factors that primarily determine water surface evaporation. Furthermore,multivariate nonlinear stepwise regression forecasting models between water surface evaporation and the selected factors were built. Both the Dalton equation and Penman equation were used in this study to compute evaporation from water surfaces,with their wind functions being modified based on the observed wind velocity at 2 m height above the water surface. Finally the multivariate nonlinear stepwise regression models were compared with evaporation estimated from the Penman equation and Dalton equation. By using the multivariate stepwise regression analysis method,factors with varying significance could be ordered,with insignificant factors being removed from the subsequent analysis and factor correlation being reduced. Wind speed,saturated vapor pressure deficit and net radiation were identified as three most important factors determining water surface evaporation in the study area. The fitting of the optimal equation was satisfactory,indicating a coefficient of determination of 0.77 between the original equation and the optimized equation. All these forecasting models were generally consistent with the observations. Results of daily evaporation from the Dalton equation,the Penman equation and the optimal equation were almost the sam