| Hydrological model is an important tool for simulating hydrological processes and understanding hydrologic regulars,As a key factor for generalization of hydrological processes,model parameters are important indicators to reflect the progress of water generation and concentration.The quantitative analysis the effect of model parameters on runoff simulation in different characteristic stages has an important scientific significance and the applied value for deep cognitive model structure,improving the simulation results,and scientifically estimate the change characteristics of water resources in the basin.Therefore,This paper takes the source region of the Yellow River,which is called the water tower in the Yellow River basin as an example,the change characteristics of hydro-meteorological elements in the basin is studied.From the perspective of rainfall and potential evaporation,the change characteristics of future water resource in the basin are evaluated,and the influence of climate change and human activities on water resources in the source region of Yellow River is analyzed.Based on that,a SWAT model for runoff simulation in source region of Yellow River is constructed The effect of parameter individual and interaction on runoff simulation was quantitatively assessed by factorial analysis;In the end,the influence of parameter combination on water resources simulation in different periods is diagnosed,and the research contents and achievements include the following aspects:(1)By using precipitation and evaporation data,In order to gain a better understanding of the temporal and spatial distribution of future water resources changes in the source region of the Yellow River,the trend analysis of Mann-Kendal(M-K)is coupled with the persistence analysis of rescaled range analysis(R/S)in this paper.The results show that the future water supply situation will be optimistic in the spring and winter seasons,and the risk of future water shortage will increase in the summer and fall;The future water supply situation of the southern region of the source region of the Yellow River will be optimistic and the risk of future water shortage will increase in eastern region of the source region of the Yellow River.(2)In order to diagnose the consistency of hydrological and meteorological elements in the source region of the Yellow River,the trend and variability of precipitation and runoff series were analyzed by Mann-Kendall mutation test and cumulative anomaly test.Using five Budyko hypotheses to quantify the impact of climate change and human activities on the changes of runoff in the source region of the Yellow River,and take Fu formula as an example,exploring the impact of changes in parameter ? on the contribution rate of climate change and human activities.The results show that the results calculated by the five formulas such as Fu,Zhang Lu,Mezentsev,Truc-Pike and Budyko are are well consistent.the contribution rates of climate change and human activities to runoff change were 59.02%?71.39%and 28.61%?40.98%respectively;By assessing the influence of the uncertainty of the parameters co on the analysis results,it is found that the contribution rate of human activity to runoff decrease is increased,and the contribution rate of the climate change is decreased.(3)Based on above results,CMADS data set and remote sensing data set are used to construct the SWAT model in the source region of the Yellow River.Among them,selected the 2008-2009,2010-2013 and 2014-2015 as warm-up,calibration and validation periods,respectively.Calibration and validation of model parameters using human-machine interaction method.The results show that the NSE is 0.73 and 0.81,respectively.The R2 is 0.82 and 0.87,respectively.The |Re| is less than 10%in both periods.The results indicate a good performance of SWAT in describing the runoff simulation based on the CMADS data in the source region of Yellow River.(4)Based on the constructed SWAT model in the source region of Yellow River,the effect of parameters individual and interaction on runoff simulation in different time periods was quantitatively evaluated by LH-OAT and factorial analysis.The results show that the uncertainty of model parameters has significant difference in different periods;The most significant parameters of the model runoff simulation are SOL_BD,SOL_BD,CN2 and SOL_BD,which are 0.99,0.26,0.60 and 0.98,respectively,in non-flood period,pre-flood period,flood period and post-flood period.The main reasons for the significant difference in the uncertainty of the parameters at different time periods can be attributed to the obvious different of the soil bulk density and the runoff curves on precipitation,temperature and evaporation in different periods;Meanwhile,the soil evaporation compensation coefficient(ESCO)and hydraulic conductivity(CH_K2)have a significant influence on the hydrologic process,which indicates that the evaporation process and the infiltration process have an impact on the hydrological process of the basin.The interaction effects of CN2 and SOL_BD as well as CH_K2 and SOL_BD are obvious,indicating that soil bulk density can impact the amount of loss generated by surface runoff and river recharge to groundwater.(5)Analysis of the results of water resources simulation with different combinations of parameters,and found that the variation of different parameter combinations led to significant differences in annual runoff simulation.Results show 2011 is the most significant impact,followed by 2010,2013,2012;By analyzing the precipitation and drought times of 3,5,7 and 9 consecutive days in the year,it is found that the uneven distribution of precipitation and the occurrence frequency of drought events are important reasons for the significant difference in runoff simulation results. |
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