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

Document Type: Research Paper

Authors

1 Desert Management Dept., International Desert Research Center (IDRC), University of Tehran , Tehran, Iran

2 R.S. and G.I.S. Dept., Faculty of Geography, University of Tehran, Tehran, Iran

3 Faculty of Agricultural Economics and Development, University of Tehran, Karaj, Iran

Abstract

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.

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