基于Budyko水热平衡改进方程的淮北平原径流变异归因分析

Attribution Analysis of Runoff Variability in Northern-Huai River Plain Based on Improved Budyko-Fu Equation

平原区地表水受大气降水、地下水开采等因素综合影响,水源转化与水循环过程复杂多变,水资源保障能力不足与三生争水严重等问题普遍存在。以淮北平原为研究区,引进有效降雨指标改进了区域年尺度Budyko-Fu(BF)水热平衡方程、进而利用弹性系数法对影响地表水资源量变化的降水、潜在蒸散发等因素的响应敏感度和贡献度作出定量评价。结果表明,所建立淮北平原水热平衡改进方程(BF-NH)模拟蒸散发系列的均方根误差较BF方程降低约50%,可更准确描述降雨等因素对区域实际蒸散发的影响。1956—2021年期间径流深随着区域降雨量增多、潜在蒸散发降低等因素变化,呈现缓慢增大趋势、年增长率约0.40 mm/a。究其原因,区域降水、潜在蒸散发、水储量变化分别贡献73.1%、19.9%、7.0%,区域降水量是影响淮北平原径流变化主导因素。

The surface water resources in plain areas are affected by a combination of factors such as precipitation and groundwater exploitation,leading to complex transformations and water cycles.Issues like insufficient water resource security capacity and competition for water among different sectors are common.This study is carried out in the Northern Huai River Plain.This study introduces an effective rainfall indicator with an emphasis on improving the annual-scale Budyko-Fu(BF)water-heat balance equation.Subsequently,the elasticity coefficient method is used to quantitatively evaluate the response sensitivity and contribution of precipitation,phreatic evapotranspiration,and other factors to the variation in surface water resources.The results show that the root mean square error of the evapotranspiration series simulated by the improved equation of water and heat balance(BF-NH)in the Northern Huai River Plain is about 50%lower than that of the BF equation,which can more accurately describe the influence of rainfall and other factors on the regional actual evapotranspiration.From 1956 to 2021,the runoff depth increased slowly with the increase in regional rainfall and the decrease in evapotranspiration of soil phreatic water,and the annual growth rate was about 0.40 mm/a.Regional precipitation,phreatic evapotranspiration,and water storage contribute 73.1%,19.9%,and 7.0%,respectively,indicating that regional precipitation is the main factor affecting runoff variation in the Northern Huai River Plain.