Comparison of the suitability of standardized precipitation index (SPI) and aggregated drought index (ADI) in Minab Watershed (Hormozgan Province/South of Iran)

Drought is a climatic anomaly, characterized by shortage (lack) of rainfall, high evaporation and unsuitable distribution of rainfall. This study investigated and compared the aggregated drought index (ADI) and standardized precipitation index (SPI) for drought monitoring in Minab watershed in Hormozgan province in south of Iran. Precipitation data were used for SPI calculation. Four variables including precipitation, potential evaporation, temperature and peak discharge (4 available recorded data) were used for ADI calculations using principal component analysis (PCA). Results of SPI show that watershed has normal drought situation from 1980 to 2009. On the other hand, ADI shows capability to detect dry and wet years. Moreover, it has capability to detect historical drought. Overall, by considering the results, the ADI is more reliable than SPI for drought monitoring in the study area.