The Applicability of the Drought Index and Analysis of Spatiotemporal Evolution Mechanisms of Drought in the Poyang Lake Basin

Poyang Lake, the largest freshwater lake in China, is an important regional water resource and a landmark ecosystem. In recent years, it has experienced a period of prolonged drought. Using appropriate drought indices to describe the drought characteristics of the Poyang Lake Basin (PLB) is of great practical significance in the face of severe drought situations. This article explores the applicability of four drought indices (including the precipitation anomaly index (PJP), standardized precipitation index (SPI), China Z-index (CPZI), and standardized precipitation evapotranspiration index (SPEI)) based on historical facts. A systematic study was conducted on the spatiotemporal evolution patterns of meteorological drought in the PLB based on the optimal drought index. The results show that SPI is more suitable for the description of drought characteristics in the PLB. Meteorological droughts occur frequently in the summer and autumn in the PLB, with the frequency of mild drought being 17.29% and 16.88%, respectively. The impact range of severe drought or worse reached 22.19% and 28.33% of the entire basin, respectively. The probability of drought occurrence in the PLB shows an increasing trend in spring, while in most areas, it shows a decreasing trend in other seasons, with only a slight increase in the upper reaches of the Ganjiang River (UGR). One of the important factors influencing drought in the PLB is atmospheric circulation. The abnormal variation of the Western Pacific Subtropical High was one of the key factors contributing to the severe drought in the PLB in 2022. This study is based on a long-term series of meteorological data and selects the drought index for the PLB. It describes the spatiotemporal distribution characteristics and evolution patterns of drought and investigates the developmental path and influencing factors of drought in typical years. This study provides a reliable scientific basis for similar watershed water resource management

Study of Water Resource Allocation and Optimization Considering Reclaimed Water in a Typical Chinese City

Reclaimed water is considered to be an important alternative to freshwater to solve the imbalance between the supply and demand of regional water resources; it is also recognized as an effective tool for alleviating ecological problems caused by insufficient water flow. Yiwu City is a typical area experiencing a water shortage in southeastern China because the regional water resources are limited. In this study, the multiple water resource allocations in Yiwu City are optimized, the complex coupling model of multiple water resource allocation is established, and both the economic and ecological effects of multiple water resource allocation in Yiwu City are simulated and analyzed. The simulation results of optimizing the multiple water resource allocations show an efficient way of reclaimed water utilization in this typical Chinese city. In order to ensure the future economic and social development of Yiwu City, it is necessary to introduce reclaimed water into different fields, such as residential water, industrial water, agricultural water, and environmental water. Reclaimed water has also proven to have a high capability for pollutant control and reduction, which is also important to the ecology and environmental protection

AdS/CFT Correspondence in Hyperbolic Lattices

The AdS/CFT correspondence, also known as the gravity/gauge duality, posits a dual relationship between the theory of gravity in Anti-de Sitter (AdS) space and conformal field theory (CFT) defined on its lower-dimensional boundary. This correspondence provides a means of mapping problems from one theory to the other, offering insights into quantum gravity and quantum field theory. Despite its importance in contemporary physics, the AdS/CFT correspondence remains a conjecture, and further experimental investigation is highly sought after. Here, we experimentally explore the AdS/CFT correspondence in both conventional type-I and previously overlooked type-II hyperbolic lattices, as the discretized regularizations of spatial geometries of pure AdS2+1 spacetime and AdS2+1 black hole. Using time-resolved and pump-prob measurements, we identify distinct geodesic behaviors in the absence or presence of an analogue black hole. Moreover, we experimentally confirm two pivotal theoretical predictions of the AdS/CFT correspondence: the Ryu-Takayanagi (RT) formula that characterizes the entanglement entropy of the boundary CFT2 through the minimal geodesic in the spatial section of bulk AdS2+1, and the exponential dependence of the boundary-boundary two-point correlation function on the hyperbolic distance which determines the conformal dimension of the boundary CFT1 associated with the scalar field mass in the bulk Euclidean AdS2 (EAdS2). This initial experimental effort opens a new avenue for future investigation on the gravity/gauge duality and the exploration of quantum-gravity-inspired phenomena in classical systems