The Inversion Of The Regional Water Reserves, Based On The Gravity Satellite Data

The gravity satellite technologies, rised in the last 70's, provides a new pathway to access the information and data of global climate change and the global water cycling, which not only solved limitation of the triditional hydrological methods for detecting change globally or regionally, but also provides a new way for detecting parameter from the water cycling and its local response. As one of the new generation of gravity satellites, using GRACE data and its time-variable product to detect the total water storage has been widely proved. This paper is mainly analyse the GRACE time-variable gravity field based on the understanding of the technoloies used in GRACE satellite programme and the high precision of the Earth's gravity field models. Meanwhile, methods of estimating water storage change by the time-varying gravity field data has been specificly analysed, including the application of Gaussian smoothing function, the replacement of low order spheric harmonic coefficients, and the truncation of infinite degree spheric harmonic coefficients.Two global hydrological models VIC model and CLM model from GLDAS system are introduced as a reference, to verify the GRACE estimates of water storage changes. The results show that changes in total water storage on hydrological model reflects the changes mainly as soil moisture change, which is consistent with the previous. Compared with the hydrological model data, the result also proved the GRACE based water storage estimating the total terrestrial water storage.As last , Poyang Lake watershed and wetland areas has been selected as the experimental area, compare the series water storage change from GLDAS global hydrological models and GRACE time-variable gravity field based water storage estimating. The result shows that, GRACE based water storage estimating the total water storage changes in annual and seasonal scales is perfectly fited with top two hydrological model presently, also shows that is able to clearly reflect the water storage variations of the studying site. Meanwhile, the results also point out that the expression of GRACE data in smaller time scale is not promising. This study provides a forward-looking conclusions about studis on regional water cycling, and while using the time-variable gravity more detailed from GOCE programme mass distribution of the Earth's system can be learn more precisely, It is perspective that gravity satellite data can be applied more effectively in the studies of global climate change and local environment response.