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Drought forecasting, which can enable contingency actions to be implemented in advance of a drought, plays a significant role in reducing the risks and impacts of drought. In this study, a simulation framework of the occurrence probability of drought events based on a nested copula function and Gibbs sampling is proposed to effectively compensate for the high-dimensional problems and lack of initial data in traditional methods. Precipitation data of 718 meteorological stations from 1961 to 2018 in China was analyzed. The results showed that the occurrence location of drought events was mainly concentrated from 35° to 42° north latitude and 105° to 120° east longitude, with the occurrence time mainly concentrated from September to November. The Archimedean-copula function, constructed based on latitude, longitude, and occurrence time, could precisely determine the spatiotemporal joint probability distribution of drought events (RMSE: 0.01). The optimal time-varying nested Archimedean-copula functions were obtained from February to May (spring), June to September (summer) and October to January (autumn and winter). Compared with the nested Archimedean-copula function, the accuracy of Gibbs sampling and simulation based on the time-varying nested Archimedean-copula function was increased by 84.05% latitude and 69.76% longitude. The results provide an effective means for scientific drought forecasting, and water resource management departments can take preventive measures at an early stage. [ABSTRACT FROM AUTHOR]

Water resources are the foundation of economic development, social progress and ecological security, and water shortage is the primary problem facing China. Water quotas have great practical significance for the resolution of water shortages to achieve sustainable use of water resources and sustainable development of the national economy. In this study, to analyse the problems and countermeasures of the water quota system in China, the water quota system progress domestically and abroad, the water quota problem in China, and the countermeasures for the water quota problem are summarized. The data validity test, spatial correlation test and consistency test are used to test the rationality of water use quota. And the specific countermeasures are presented: improving the water quota system, defining its concept, and revising its scheme, etc. This study provides the support to standardize water quotas and implement the effective water conservation policies of China. [ABSTRACT FROM AUTHOR]

Water crisis is prominent in the Beijing-Tianjin-Hebei region, therefore, the internal relations between water utilization changes and socioeconomic development must be urgently analysed. Based on analyses of the spatiotemporal characteristics of total water utilization, the factors that influenced changes in industrial water utilization in the Beijing-Tianjin-Hebei region from 2003 to 2016 were studied using a factor decomposition model. The results show that the scaling effect (SCE) increased water utilization by 31.78 billion m3 over those 13 years and was the only driving effect that caused industrial water utilization to increase. The structural effect (STE) and technological effect (TEE) reduced industrial water utilization by 14.93 and 20.44 billion m3, respectively. The TEE was the main reason for the decrease in industrial water utilization in Beijing, accounting for a reduction of 96.5% in total industrial water utilization. The STE was stronger than TEE in Tianjin, with associated decreases of 94.65% and 90.1% in total industrial water utilization, respectively. In Hebei, the STE and TEE reduced total industrial water utilization by 60.23% and 85.46%, respectively. Adjusting the industrial structure and promoting water-saving technology are efficient methods of alleviating the water shortage in the study area. [ABSTRACT FROM AUTHOR]