Ranking and optimizing the rain-gauge networks using the entropy–copula approach (Case study of the Siminehrood Basin, Iran)

Abstract

The existence of reliable rain-gauge networks is a necessity in managing water sources and the relevant environmental issues in any basin. The present study aimed to investigate the rain-gauge network and rank the rain-gauge stations in the Tazehkand sub-basin in the southwest of Lake Urmia, Iran, using the entropy–copula approach using the data obtained from six rain-gauge stations in the Siminehrood basin in Northwestern Iran between 1981 and 2019. The interaction effects of the stations were investigated using the copula simulation approach instead of the multivariate regression analysis. The R-vine was selected as the most convenient copula after investigating various vines using the statistics related to error investigation. Then, the interaction effects of the stations were investigated using the R-vine. The rainfall in each station was estimated by considering the rainfall of other stations. Moreover, the more prevalent multivariate regression analysis was implemented, and its results were compared with the results obtained from the vine simulation approach. The results of the comparison according to the NSE statistic showed that the vine simulation approach was above 90% across all stations. The estimates for the ITI and N(i) indices of each station using the entropy theory showed the shortage of stations in the investigated area. The stations were in average, above-average, and surplus modes according to the ITI index. The rating concerning the N(i) index indicated that the Dashband station was the most appropriate one in terms of communicating with other stations and conveniently covering the plain.