基于改进的Green-Ampt入渗模型重建清光绪初年山西大旱降雨入渗量

Reconstruction of rainfall infiltration of the extreme drought in Shanxi Province in early years of Emperor Guangxu of the Qing Dynasty based on improved Green-Ampt infiltration model

为了深入挖掘和充分利用清宫档案“雨雪分寸”所反映的降水信息,重建清光绪初年山西极端干旱事件,本文在山西省开展了人工模拟降雨入渗试验,探讨了利用改进的Green-Ampt入渗模型求解山西省累计入渗量方法的可靠性与适用性,并利用山西省1875—1878年主汛期“雨分寸”资料重建了历史时期土壤降雨入渗量。结果表明:(1)降雨量是山西省降雨入渗湿润锋推进深度的主要因素,两者呈明显的正相关;(2)改进的Green-Ampt入渗模型在山西省具有较好的适用性,实际入渗量与模拟值的纳什效率系数在0.8以上,且两者相关性显著;(3)1875—1878年山西主汛期6—9月降雨累计入渗量普遍较少,土壤干旱较为严重。

In order to make full use of the precipitation information from rainfall and snow records in the Qing Dynasty archives,and to reconstruct the precipitation sequence of extreme drought event in Shanxi in the early years of Emperor Guangxu of the Qing Dynasty,artificially simulated rainfall infiltration experi⁃ments were carried out at two representative sites in Shanxi Province.The improved Green-Ampt infiltration model based on the wet distinction layer is introduced to simulate the cumulative infiltration in Shanxi Prov⁃ince,on condition that the model applicability was tested.Finally,the amount of soil rainfall infiltration in main flooding season of 1875-1878 is reconstructed by using the rainfall records in the Qing Dynasty ar⁃chives.The results show that:(1)Rainfall is the main factor for the advancement of rainfall infiltration wet front in Shanxi Province,and there is a significant positive correlation between the two variables.(2)The improved Green-Ampt infiltration model has good applicability in Shanxi Province.For both of the two experiment sites,the Nash efficiency coefficients are above 0.8,and the correlation between the actual infil⁃tration value and simulated value is significant.(3)The simulated cumulative rainfall infiltration from June to September in the main flooding season in Shanxi from 1875 to 1878 was relatively less,indicating se⁃vere soil moisture drought.