Research On Water Resources Simulation Of Weihe River Basin Based On Multi-source Remote Sensing Data

In recent years,under the influence of climate change and human activities,the evolution law of water cycle elements such as precipitation and runoff in Weihe River Basin has changed o,bviously,and the runoff has decreased significantly,which has seriously restricted the development of local economy.Therefore,the simulation study of water resources in Weihe River Basin can provide scientific reference for local water resources management.Based on the Tropical Rainfall Measuring Mission(TRMM)satellite data,MODIS(Moderate-resolution Imaging Spectroradiometer)satellite remote sensing data,and GRACE(Gravity Recovery And Climate Experiment)gravity satellite data,this study inverts and obtains water cycle elements such as precipitation,evapotranspiration and water storage in Weihe River Basin separately.According to the water balance equation and Fu Baopu's evapotranspiration empirical formula,a water-heat coupling model is established.The key hydrological elements such as precipitation,evapotranspiration,and water storage changes are used as model input items.The model parameters are verified using measured runoff data,and the application of remote sensing data is analyzed applicability in runoff simulation based on water-heat coupling model.The study contents and achievements of this paper are as follows:(1)The precipitation is obtained by the TRMM satellite data,and the accuracy of the TRMM data is evaluated by the measured precipitation data of meteorological stations.The results show that the TRMM precipitation in Weihe River basin is consistent with the measured data(correlation coefficient R=0.99,relative error BIAS=6.96%),but there are differences between the two in some stations.The corrected relative error is 2.66%,indicating that the corrected TRMM data can be applied to runoff simulation in Weihe River basin.From 1998 to 2018,the precipitation in the Weihe River Basin generally showed an increasing trend,mainly concentrated in the flood season(July to September)during the year,showing obvious seasonal changes.The average annual precipitation of the basin is 585.62mm,and the precipitation trend is gradually increasing from northwest to southeast.(2)Using MODIS satellite data to obtain evapotranspiration in the Weihe River Basin.The results show that from 2000 to 2014,the average annual evapotranspiration of the Weihe River Basin was 459.61mm,of which the annual average evapotranspiration in the basin was the smallest(392.04mm).In 2003,the average annual evapotranspiration reached a maximum of 517.09 mm.Overall,the evapotranspiration in the Weihe River Basin showed an increasing trend with a growth rate of 3.361 mm/a.The annual average evapotranspiration in the river basin showed a distribution characteristic of low northwest and high southeast.In addition,the water-heat coupling model based on Fu Baopu's formula reversed evapotranspiration,and verified the Fu Baopu's evapotranspiration with the MODIS evapotranspiration results,and found that Fu Baopu's evapotranspiration and MODIS evapotranspiration has a consistent change trend,indicating that Fu Baopu's evapotranspiration can be applied to model runoff simulation.The results of the reverse Fu Baopu's evapotranspiration have a highly consistent change trend with precipitation.(3)The GRACE gravity field model is used to invert the water storage of the Weihe River Basin from 2003 to 2015.The basin water storage variation and GLDAS(Global Land Data Assimilation System)of the hydrological model to estimate the variation of river basin water reserves,precipitation,groundwater depth variation has roughly the same change rule,it shows that GRACE inversion result have certain reliability.In December 2015,the water storage in the Weihe River Basin changed the least,with a value of-58.3mm.In July 2003,the water storage changed the most,with a value of 62.13mm.According to the results of the change of the average water storage in the basin over the years,the water storage in various regions of the river basin have reduced to different degrees.The overall trend is gradually decreasing from northeast to southwest.(4)Using the remote sensing inversion results of precipitation and water storage and the calculation results of potential evapotranspiration,the water-heat coupling model is constructed based on the water balance theory,and the model is verified by the measured runoff data from the Huaxian hydrological station.The results show that the water-heat coupling model has good simulation accuracy on the annual scale,and the overall simulation results are close to the measured runoff.Therefore,the application of remote sensing data to the water-heat coupling model on the annual scale has a good applicability.