Budyko假设对松花江流域实际蒸散发的模拟研究

A Simulation Study of Actual Evapotranspiration in Songhuajiang River Basin Based on Budyko Hypothesis

基于Budyko假设,考虑土壤水蓄变量因子,改进流域水热耦合平衡方程,验证了Budyko假设在松花江流域的适应性,分析了松花江流域实际蒸散发(ET_a)的时空变化特征及其驱动机制。主要结论如下:(1)以1995～2006年作为模型参数率定期,2007～2012年作为模型检验期,用P-ΔS代表陆面蒸散发的水分供应条件,结果表明,增加土壤水蓄变量因子,提高了模型对实际蒸散发的模拟精度。(2)在α=0.1的显著性水平下,1995～2012年各汇水区ET_a均没有趋势性变化;ET_a在空间上由西向东逐渐增加,存在明显的地带性。(3)降水对ET_a的贡献量空间变化与潜在蒸散发、降水、土壤水蓄变量对ET_a总贡献量空间变化一致,表明松花江流域的水分条件是影响实际蒸散发的主导因素。

Based on the Budyko hypothesis, this paper improved the water-energy balance equation integrating soil water storage variable factors, and verified the adaptability of Budyko hypothesis in the Songhuajiang River basin, and analyzed the spatio-temporal variability of actual evapotranspiration and its driving mechanism. The main results are as follows:(1) taking 1995-2006 as the model parameter calibration period and 2007-2012 as the model verification period, using P-ΔS to represent the water supply conditions for land surface evapotranspiration, which indicate that soil water storage variable factors have improved the calculation accuracy of actual evapotranspiration.(2) Under the significance level of α=0.1, there is no significant trend in the ET_a of each catchment from 1995 to 2012;the spatial distribution of ET_a gradually increases from the west to the east and has obvious zonality.(3) The spatial variation of the contribution of precipitation to ET_a is consistent with the spatial variation of total contribution of the potential evapotranspiration, precipitation and soil water storage variables to ET_a, which indicate that the water condition of the Songhua River basin is the dominant factor affecting the actual evapotranspiration.