Retrieval of groundwater storage anomalies in eastern region of Korla by downscaling GRACE/GRACE-FO data
Despite the gravity recovery and climate experiment(GRACE)and GRACE follow-on(GRACE-FO)satellites pro-vide a new capability for retrieving and monitoring of global large-scale groundwater storage anomaly(GWSA),its data prod-ucts struggle to provide access to small-scale GWSA information with high spatial resolution.In this paper,a dynamic down-scaling method was employed to improve the spatial resolution of GWSA data retrieved by GRACE/GRACE-FO and to analyse the spatio-temporal distribution of GWSA in the eastern area of Korla,Xinjiang,China.Firstly,a GWSA numerical model of eastern region of Korla was constructed and optimized based on data fusion for purposes of the spatial downscaling conversion.Then,the resolution of GRACE/GRACE-FO-derived GWSA data was downscaled from 1° to 0.25° and 0.05° via the optimized model.The derived GWSA results were further compared with the well-monitored groundwater level(GWL)data.Finally,the GWSA trends in specific study areas were evaluated using 0.05° GWSA data.Specific results include:①Compared to the 1° GWSA without downscaling transformation,the high-resolution GWSA data after downscaling are spatially smoother and more detailed,whose correlation with the GWL monitoring data is increased,indicating an improvement in inversion accuracy and re-liability.②At small scales,the downscaled GWSA can reflect the ground water regime,such as seasonal and interannual varia-tions,as well as long-term depletion,in specific water sources.③The GWSA in the eastern area of Korla states the character-istics of spatial and temporal differences,whose trends from 2005 to 2020 are-1～1 mm·a-1,generally following an increas-ing tendency in the south and a decreasing tendency in the north.Specifically,the GWSA slopes in the southern and northern mountainous zones are greater than those in the relatively flat central region.
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万方数据
