黄土丘陵沟壑区自然条件下不同辐射面蒸发蒸腾量的预测

Prediction of Evapotranspiration from Different Radiation Surfaces Under Natural Conditions in the Loess Hilly and Gully Region

基于黄土丘陵沟壑区自然条件下的田间试验,利用TDR测定了研究区不同辐射面15个不同坡面的含水量,基于水量平衡法计算得到蒸发蒸腾量,揭示了不同辐射面蒸发蒸腾量的变化规律,研究了坡向、坡度对蒸发蒸腾量的影响,在此基础上构建了预测模型,并对其预测结果进行了验证。研究结果表明:①黄土丘陵沟壑区蒸发蒸腾量在越冬期过后,逐渐增大,4月底达到第一个极值;进入6月雨季之前,缓慢减少,雨季之前达到最小值;进入雨季后,逐渐增加,8月底达到最大值;雨季结束后,呈现出逐渐减小的趋势。②坡向和蒸发蒸腾量之间有一定的相关性,接近正南区域阳坡的月度ET值为最大值;坡度和蒸发蒸腾量之间也有一定的相关性,坡度越大,蒸发蒸腾量越小,反之亦然。③采用水量平衡法对研究区蒸发蒸腾量进行预测,从模拟结果来看,所构建的模型能够很好地对黄土丘陵沟壑区自然条件下不同辐射面ET值进行预测。研究结果对黄土丘陵沟壑区农业生产、灌溉制度的制定、缓解水资源短缺现状、实现基于蒸发蒸腾量的水资源管理模式具有重要意义。

Based on field experiments under natural conditions in the loess hilly and gully region,this paper used TDR to determine the water content of 15 different slopes on different radiation surfaces in the study area,calculated the evapotranspiration based on the water balance method,and revealed the change rule of evaporation in different radiation surfaces.The change law of evapotranspiration and the influence of slope aspect and slope on evapotranspiration was studied,a prediction model was constructed on this basis,and the prediction results were verified.The results showed that:①The ET value in the loess hilly and gully region gradually increased after the wintering period,reached the first extreme value in early April;before entering the rainy season in June,it decreased slowly,and reached the minimum value before the rainy season;after entering the rainy season,it gradually increased and reached the maximum at the end of August;after the end of the rainy season,it showed a gradually decreasing trend;②There was a certain correlation between the aspect and the ET value,and the ET value was close to the maximum value of the sunny slope in the southern region;There was also a certain correlation between the slope and the ET value.The larger the slope,the smaller the ET value,and vice versa;③The water balance method was used to predict the evapotranspiration in the study area.From the simulation results,it can be seen that the established model can well predict ET values of different radiation surfaces in the loess hilly and gully region under natural conditions.The research results are of great significance for agricultural production,irrigation system formulation,water resource shortage alleviation and realizing water resource management mode based on evapotranspiration in loess hilly and gully region.