Agricultural Drought Monitoring Using Reconnaissance Drought Index (RDI) and Kriging Geostatistical Model (Case Study: Central and Southern Regions of Fars Province)

Drought is one of the most important natural disasters that due to the frequency of occurrence needs to be assessed and monitored, especially in the field of agriculture. In the present study, the Reconnaissance Drought Index (RDI) was used to monitor drought and spatially assess its severity in central and southern regions of Fars province. The relationship between the severity and duration of drought during different years of the statistical period (1990-1991 to 2012-2013) was investigated. Kriging model was used in the geographic information system (GIS) environment for spatial evaluation. Based on the comparison between the different semivariogram of the kriging model, the most suitable model was selected. Based on the results of drought severity, its continuity and trend were determined during the statistical period. The results showed that severe droughts occurred in Darab and Neyriz stations during 2000-2002 and 2008-2010. In Fasa and Jahrom stations, in most of the years, climate fluctuations have led to drought with low to high intensities. At Larestan station, the results also showed several droughts have occurred, especially during the years 2000 to 2010. In spatial evaluation of drought using the Kriging model, the results showed that the best semivariogram is the spherical model. The evaluation of drought vulnerability in the studied areas also showed that the northern areas of Nayriz, Estahban, Fasa, Darab and Larestan have suffered more damage. Therefore, the use of drought indices, drought intensity monitoring and mapping methods are essential for better management and planning for advance planning and it is recommended for water resources management decisions.