Analysis and Prediction of Terrestrial Water Storage Anomalies in the Lower Yangtze River Basin Based on an Improved Grey-Markov Model

Li, X.; Wang, B.; Tong, Z.; Jiang, Z., and Cai, C., 2023. Analysis and prediction of terrestrial water storage anomalies in the lower Yangtze River Basin based on an improved Grey-Markov model. Journal of Coastal Research, 39(3), 544–552. Charlotte (North Carolina), ISSN 0749-0208. The data from Gravity Recovery and Climate Experiment (GRACE) satellites have been used to estimate terrestrial water storage anomalies (TWSAs) in many areas. From the former studies, the TWSAs from GRACE have been proven as a sensitive indicator to extreme hydrological events, which means it is possible to forecast the extreme hydrological events through the prediction of TWSA. However, because of the limited time series and missing data of the GRACE satellite, it is still very difficult to analyze the long-term TWSAs and predict the future changes of TWSAs. In this paper, the TWSAs of the lower Yangtze River basin from 2002 to 2021 estimated by the GRACE are compared with the TWS from Global Land Data Assimilation System (GLDAS) with the aspects of trend and correlation. The TWSAs from GRACE and the TWS from GLDAS in the study area are both on a slight upward trend. The Pearson correlation coefficient and the spectral analysis present a strong correlation between the two elements. According to the high correlation between the two elements, both linear and nonlinear methods are used to reconstruct a long-term GRACE data, and an improved Grey-Markov model is proposed to predict the future TWSA in the study area. The results show that a linear relationship occurs between the two elements. Moreover, the forecast results show that the TWSA of the lower Yangtze River basin will exceed 0.35 cm in 2021 and 2022, indicating continuous wet conditions in the basin. The basin should be prepared for the occurrence of floods.