基于Budyko理论的北京地区实际蒸散发估算及特征研究

为了探究近些年北京地区实际蒸散发的时空变化特征,采用基于Budyko理论的傅抱璞经验模型,对北京地区1980-2016年实际蒸散发进行了估算;并根据Mann-Kendall趋势分析、相关分析等方法,对研究区实际蒸散发的时间变化特征、空间格局以及影响因素进行了探讨;为提高傅抱璞经验模型在研究区的适用性,依据北京地区历史时期水文气象数据,结合水量平衡法对该模型参数进行了校准和验证。结果表明:优化参数后的经验模型在研究区具有较高的模拟精度,且适用性较强;北京地区多年实际蒸散发均值为447 mm;时间尺度上,呈不显著的下降趋势;空间上,表现出明显的空间异质性,其中,蓟运河山区的蒸散发最大,其次为潮白河流域东部;实际蒸散发的这种时空变化特征与区域降水量密切相关。

Estimation and variation of actual evapotranspiration of Beijing region based on Budyko theory

For the better understanding of the actual evapotranspiration (AET) of Beijing region from 1980 to 2016, the AET was estimated using the Budyko based empirical model proposed by Fu Baopu, which excels at the estimation of AET at basin scale. The temporal and spatial variations of AET and its influencing factors were investigated using the Mann-Kendall test method and the correlation analysis. To improve the applicability of Fu Baopu model in the study area, the parameters of the model were calibrated and validated by the water balance model together with the historical hydrometeorological data (e.g. monitored precipitation data, water surface evaporation data and runoff data). The simulation results show that this empirical model presents a high simulation accuracy and great applicability in estimating AET over Beijing region after parameter calibration. The annual mean AET of Beijing is 447 mm. At the temporal scale, the AET series from 1980 to 2016 shows a slightly decreasing trend for the whole study area. Great spatial heterogeneities are found with the largest value occurring in the mountainous area of Jiyun River Basin, followed by the east of Chaobai River Basin. Such temporal and spatial variations are highly correlated with the regional precipitation.