A Review of Copula-Based Approach for Water Resources Time Series

This research investigates the utilization of copula functions in the water resources field, encompassing meteorological and hydrological aspects. A review of the Web of Sciences archive revealed 15143 studies featuring copula keywords. Notably, 40% of these studies pertain to copula-based simulation within this field. Groundwater studies were the least conducted, accounting for only 3% of all studies in the field. Regarding copula functions, studies were generally divided into two parts: frequency analysis and simulation, encompassing all dimensions of copula functions. Researchers confirmed the performance of copula functions in both parts. Studies in copula functions have revealed a new approach in joint frequency analysis and conditional probability estimation, based on the marginal distribution of data and their conditional density. The results indicate that in more than 2 dimensions, the tree sequence of vine copula has reduced computational complications and allows for the determination of different structures based on independent and dependent variables. Various studies have shown that the use of copula functions has been successful due to its lack of assumptions and restrictions and has good performance. For this reason, this approach is considered. The approach has been increasingly utilized in 2-dimensions and multi-variables, and continues to progress and develop.