Meteorological drought monitoring using several drought indices (case study: Salt Lake Basin in Iran)

Drought detecting is a necessary aspect of drought risk management. It is generally performed using different drought indices that are effectively continuous functions of rainfall and other hydro- meteorological variables. A number of drought indices have been introduced and used in various countries to date. In the current research, four meteorological drought indices including the standardized precipitation index (SPI), China-Z index (CZI), modified CZI (MCZI) and Z-Score (Z) are compared and evaluated for monitoring droughts in Salt Lake Basin in Iran. The comparison of indices was carried out based on drought classes that were monitored in the study area using 40 years of data. The results indicated that SPI, CZI and Z-Score performed similarly with regard to drought identification and responded slowly to drought onset. DI appeared to be very sensitive to precipitation rates, but had unsteady spatial and temporal variation. Additionally, by considering the advantages and disadvantages of the mentioned drought predictors in Iran, the CZI and ZScore could be used as good meteorological drought predictors.