Using GIS to monitor drought based on Standard Precipitation Index (SPI) for...

Using GIS to monitor drought based on Standard Precipitation Index (SPI) for Khorasan Province of Iran



Seyed Hossein
S. H. Sanaei – Nejad
Ferdowsi University of Mashhad, P.O.Box: 91775-1163
Tel: +98 511 8410863-5, Fax: +98 511 8415845

Drought is a creeping natural hazard, which is caused by short raining and humidity deficit. , When a drought occurs dramatic social, economic and environmental effects are inevitable. Because of the vast impact of drought, it is essential to be monitored timely and spatially. We studied drought periods in Khorasan using 33 years climatic data (1968- 2000). We concluded that drought is a natural climatic feature of the regions and occurs time by time in specific periods.

The study showed that during last years recurring drought has been more frequent and also it lasted longer than the early years. However, the severity of drought has been reduced. We used different methods to interpolate drought data for spatial analysis using Geographic Information Systems (GIS).

We then concluded that Kriging method is suitable for this analysis this method was used for zoning drought over Khorasan province and produced zoning map of drought severity for different time scales.

The study showed that the duration and severity of drought is more in the sought area than in the central and northern parts of the province. The most sever drought periods during the years of study occurred in 1970th and 1990th.

We prepared a model to calculate SPI and prepare zonong maps for the index over the province periodicaly. We also established a web site to broadcast the maps for drought monitoring purpose