1 How can we calculate meteorological drought indices? There are eight famous rain-based meteorological drought indices. We calculate this indices as following: - SPI (Standardized Precipitation Index) SPI is a widely recognized tool for characterizing...
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1 How can we calculate meteorological drought indices? There are eight famous rain-based meteorological drought indices. We calculate this indices as following: - SPI (Standardized Precipitation Index) SPI is a widely recognized tool for characterizing meteorological drought (Hayes et al., 1999; Deo, 2011). McKee et al. (1993, 1995) defined SPI across different timescales (1, 3, 6, 12, 24 and 48 months). The Standardized Precipitation Index (SPI) is widely used for defining and monitoring meteorological droughts. For the details of calculation, refer to McKee et al. (1993). The range of SPI is between +2.0 and −2.0. - DI (Deciles Index) The deciles index (DI) was defined by Gibbs and Maher (1967). For calculating this index, we should to sort the precipitation data in a specific format. In this approach proposed by Gibbs and Maher the total monthly precipitations from a long record is first ranked from highest to lowest to construct a cumulative frequency distribution. The severity o
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