Abstract:
Based on GRACE satellite and GLDAS assimilation system, changes of groundwater storage in the Huang-Huai-Hai Plain from 2002 to 2017 were retrieved, WGHM model was used to verify the accuracy of the data. Then, the spatiotemporal characteristics of groundwater storage in the Huang-Huai-Hai Plain were clarified by trend analysis and random forests regression method.From the view of precipitation supply and different water usage demand in different industries,the influencing factors of groundwater storages in plain is revealed. The results showed that: (1) The groundwater storage of the Huang-Huai-Hai Plain retrieved by GRACE and GLDAS were in consistent with the groundwater storage output by WGHM model, and the correlation coefficient was 0.76. The regions with high correlation were mainly distributed in the Haihe River Basin, Huaihe River Basin and Shandong Peninsula. (2) The groundwater storage in the Huang-Huai-Hai Plain showed a continuous downward trend and decreased annually at a rate of -9.36 mm/a from 2002 to 2017. The groundwater volume in the Huang-Huai-Hai Plain changed about 58.9 billion~79 billion m3 from 2002 to 2017. (3) There is an obvious seasonal change in groundwater storage in the Huang-Huai-Hai Plain, which demonstrated a seasonal cycle pattern of maximum loss in spring, slowly rose in summer, maximum surplus in autumn and slowly declined in winter. (4) In spatial terms, the groundwater in most areas of the Huang-Huai-Hai Plain showed a downward trend, except for northern Anhui and northern Jiangsu, which showed a slight upward trend. The decrease rate was -41.29 mm/a in northern Henan and southern Hebei. (5) The relative contribution rate of agricultural water and industrial water were 27.04% and 23.23% respectively, which were the main factors affecting the decline of groundwater storage in the Huang-Huai-Hai Plain.
