Water Storage Monitoring In Three Northeastern Provinces Based On GRACE Satellites During 2002-2017

The Gravity Recovery and Climate Experiment Satellite which jointly developed by Germany and the United States has provided the earth's gravity field with high precision and high spatial and temporal resolution since its' launch in March 2002.It provides a new way for quantitative study of the earth's surface mass redistribution,especially the change of water storage,and has been widely used in the study of global hydrological environment changes.As an important agricultural and industrial production base in China,the monitoring and analysis of water storage changes is of great practical significance to realize sustainable utilization of water resources and socio-economic development in Three Northeastern Provinces.This paper expounds on the basic method of the inversion of terrestrial water storage changes by GRACE time-variable gravity data.Combined filter is used to weaken the north-south strip and high-frequency error in the original data,and then the scale factor method is used to suppress the leakage error,so as to obtain the terrestrial water storage changes in Three Northeastern Provinces based on the GRACE data from April 2002 to June 2017.The groundwater storage changes in Three Northeastern Provinces are obtained after deducting the sum of the soil water and ice and snow equivalent water simulated by GLDAS data.Finally,the calculated results are compared with the measured values of groundwater monitoring wells and precipitation.The results show that the change rates of terrestrial water storage in Three Northeastern Provinces show a decreasing trend from north to south,with water storage increasing in the northern region and decreasing in the southern region.The long-term change rates from 2002 to 2017 are-0.26cm/a in Liaoning Province,0.21cm/a in Jilin Province and 0.89cm/a in Heilongjiang Province,respectively.Although the long-term change rates are different,the similar geographical location and climatic conditions make the terrestrial water storage show a similar change trend in a relatively short period of time.The terrestrial water storage shows a decreasing trend from 2002 to2008,and the rates of change are-0.27cm/a in Liaoning Province,-0.46cm/a in Jilin Province,and-0.72cm/a in Heilongjiang Province,respectively.The terrestrial water storage shows an increasing trend from 2008 to 2013,and the rates of change are1.85cm/a in Liaoning Province,1.47cm/a in Jilin Province,and 2.07cm/a in Heilongjiang Province,respectively.The terrestrial water storage shows a decreasing trend from 2013 to 2017,and the rates of change are-2.78cm/a in Liaoning Province,-1.34cm/a in Jilin Province,and-0.73cm/a in Heilongjiang Province,respectively.In terms of groundwater storage changes,GRACE satellites detect a long-term change rates of-0.48cm/a in Liaoning Province,-0.11cm/a in Jilin Province and 0.66cm/a in Heilongjiang Province from 2002 to 2017,respectively.Heilongjiang Province is the only province that has increasing trend among Three Northeastern Provinces.From2013 to 2017,the groundwater storage of Three Northeastern Provinces shows a decreasing trend,and the rates of change are-2.19cm/a in Liaoning Province,-1.34cm/a in Jilin Province,and-0.60cm/a in Heilongjiang Province,respectively.The interannual changes of terrestrial water storage calculated by GRACE and GLDAS are relatively consistent in Three Northeastern Provinces.The correlation coefficients are 0.68 in Liaoning Province,0.72 in Jilin Province and 0.78 in Heilongjiang Province,respectively,which have a strong correlation.The groundwater storage changes inversed by GRACE are relatively consistent with the measured water level changes of groundwater monitoring wells,indicating that the use of GRACE to detect changes in water storage in Three Northeastern Provinces has a certain degree of reliability.Precipitation is the main source of replenishment for the terrestrial water storage of Three Northeastern Provinces.The terrestrial water storage of Three Northeastern Provinces is in good agreement with the precipitation.The interannual variation correlation coefficients are 0.52 in Liaoning Province,0.60 in Jilin Province,and 0.60 in Heilongjiang Province,respectively.In dry years with less precipitation,the terrestrial water storage inversed by GRACE is significantly reduced.The interannual changes of groundwater storage and precipitation are relatively poor,but the changes within the year are relatively consistent,and there is a significant time lag between precipitation and groundwater storage.In summary,this paper focuses on the research of terrestrial water storage and groundwater water storage changes in Three Northeastern Provinces,provides references for GRACE data processing methods and model selection,reveals long-term changes in water storage in Three Northeastern Provinces.It is expected to provide a reference for the socio-economic development and sustainable use of water resources in the region.