Document Type : Original Article
Authors
Associate Professor, Department of Water Engineering,Department and Research Group of Drought and Climate Change, Faculty of Agriculture,University of Birjand, Birjand, Iran.
Abstract
Drought is one of the most damaging natural events, significantly impacting water resource planning due to its geographical dominance and prolonged duration. This study analyzed drought intensity and duration at Qaen meteorological station from 1998 to 2018 using the 12-month Standardized Precipitation Index (SPI). The correlation between drought severity and duration was assessed using Tau-Kendall (0.74) and Spearman (0.88) coefficients, indicating a strong relationship. Marginal probability distributions revealed that drought duration follows a normal distribution, while severity aligns with a log-normal distribution. Among various joint functions analyzed, the atmospheric joint function was identified as the most suitable model, with RMSE = 0.0924 and NSE = 0.996. This model enables accurate estimation of the probability and return periods of drought events, providing critical insights for integrated water resource management. These findings can support planners and stakeholders in developing strategies to mitigate drought impacts in the study area.
Keywords
- Bivariate analysis
- intensity and duration
- Qaen observation station
- precipitation
- marginal probability distribution
Main Subjects
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