[A-HW24] Human- and Climate-induced variability in water cycle and (sub)surface water resources

[AHW24-P08] Fill the data gap between GRACE and GRACE-FO with precipitation

*DAN FENG¹, Kenji Tanaka² (1.Graduate School of Engineering, Kyoto University, 2.Disaster Prevention Research Institute,Kyoto University)

Keywords:GRACE and GRACE-FO, data gap, precipitation, aquifer scale

GRACE(Gravity Recovery and Climate Experiment) and GRACE-FO(GRACE-Follow on) were Earth System Science Pathfinder Program jointly with the National Aeronautics and Space Administration (NASA) and German Aerospace Center (DLR). The GRACE provides a new method to estimate groundwater anomalies in large scale. Therefore, it is essential to have long-term and continuous data for hydrological analysis in the aquifer scale. There was a mission gap from July 2017 to May 2018 between the two missions. In addition, the GRACE had missing days due to instrument issues after 2011. This study aims to fill in the mission gap and missing days of GRACE and GRACE-FO data in the world´s largest 37 aquifer systems. The precipitation data from GSWP3-W5E5 was used as a predictor to reconstruct the TWSA(Terrestrial Water Storage Anomalies) in monthly scales. The missing days were filled by the average of adjacent months. Next, each month Pearson correlation between TWSA and cumulative monthly precipitation (previous 0 to 12 months) was analyzed. The corresponding highest correlation of cumulative precipitation data for the lag month was selected. The cumulative precipitation and TWSA data were used to build the linear regression model to fill the mission gap. This study introduces a linear regression method using precipitation to reconstruct the mission gap between the GRACE and GRACE-FO missions and provides continuous TWSA products for groundwater analysis in the aquifer scale.