Research On Method And Application Of Recovering Terrestrial Water Storage's Variation Based On GRACE Data

The temporal gravity field mainly includes the redistribution of the earth's mass on the seasonal and interannual time scales.The changes on seasonal or shorter time scales mainly reflect the variation of terrestrial water storage.Satellite gravity detection technology is applied to the monitoring of variation in terrestrial water storage at medium to long-term spatial scales.The global distribution is even and the observation scales are unified.It has provided new monitoring tools for studying global hydrological issues.In particular,since the successful launch of the GRACE satellite in 2002,the space-time resolution of the gravitational field has been significantly improved.The GRACE satellite has been widely used in the fields of hydrology and global environmental change.However,because it is difficult to obtain real-world observations of terrestrial water storage,evaluating GRACE data products issued by different research institutions and obtaining better inversion results are the focus and difficulties of related research.This article focuses on the topic of the application of GRACE satellite data in hydrology,studies and compares different filtering methods in the GRACE data processing process.The hydrological model was used to compare and verify the inversion results.Combining the data of hydrology,meteorology and other data,the consistency and difference of the inversion results of the two are analyzed,and the reasons and trends of the variation of water storage in the study area are discussed.In this paper the main work and research results are as follows:(1)Using GRACE Level-2 RL05 data product,according to the fundamental principle of time-varying gravity field inversion of surface quality,the effects of Gaussian filtering,Fan filtering,and decorrelation filtering methods on the gravity field model error were studied.The selection of filter parameters is discussed.It is found that the decorrelation filter can effectively weaken the error of the north-south strip.In the same filtering radius,the effect of Fan filter is better than that of Gaussian filter.Considering the error type and spatial resolution comprehensively,a combined filtering method is recommended.(2)We used the GRACE data from January 2003 to November 2013 to invert the variation of terrestrial water storage in the Tibetan Plateau,and compared the inversion results with GLDAS.The results showed good agreement between the two models.Compare and analyze when divided the time period into the former 5 years and the latter 6 years,the water storage derived from GRACE has the same trend with that derived from GLDAS in both time periods respectively.And both the two models can reflect the sharp decline of the water storage during the end of 2009 to early 2010 caused by the drought in Southwest China.