Data Processing And Application Of GRACE Gravity Satellite

The launch of GRACE gravity satellite opened a new era of high-precision observation of global environmental changes.Based on GRACE satellite data,we explore and improve the data processing method,then use this method to invert terrestrial water storage change in Henan Province.Firstly,the GRACE satellite data needs to be denoised by filtering method before it can be used in the inversion of terrestrial water storage change.In this paper,the data is processed by Gaussian filtering method and two different de-correlation filtering methods combined with Gaussian filtering.The results show that the denoising effect becomes better with the increase of the smoothing radius of Gaussian filtering.They also show that the combination of Swenson,Wahr de-correlation filtering and Gaussian filtering method is superior to the combination of P4M6 de-correlation and Gaussian filtering method,but there still exists band phenomenon when the smoothing radius is 300 km.Therefore,we choose to improve the Gaussian filtering method,and the results show that the improved Gaussian filtering method is better than the unimproved method.Secondly,we use the improved hybrid Gaussian filtering method combined with Swenson,Wahr de-correlation filtering to process the data,then use the processed data to invert the terrestrial water storage change in Henan Province.The time series diagram shows that the terrestrial water storage change in Henan Province has typical seasonal fluctuation characteristics.The trend of this change is then analyzed by linear fitting and it is found that there is a decreasing trend during the observation period,which indicates that the water storage in Henan is decreasing.Finally,we use the GLDAS hydrological model data,precipitation data and water resources bulletin data released by Henan Water Resources Department to verify the result,then use correlation analysis to analyze the result with GLDAS hydrological model data and precipitation data,respectively.From which we obtain that using the GRACE gravity satellite to invert the terrestrial water storage change in Henan Province is feasible,and that the GRACE gravity satellite can be used not only in monitoring the terrestrial water storage change of global or large-scale regional areas but also of smaller administrative regions.