Visualization and Spatio-Temporal Analysis of Drought using SPI and DI

Drought is some deficiency of precipitation that results in water shortage for someactivities related to the use of water. This investigation was undertaken to analyze andvisualize drought hazard in the Urmia Lake basin. To accomplish this goal, we usedStandardized Precipitation Index (SPI) and performed several spatio-temporal analysesand a validation assessment using the Decile Index (DI). Monthly precipitation datafrom the observational period 1986–2011 from 7 meteorological gauges were used tocompute the duration, severity, and extent of meteorological droughts. The SPI wasvalidated by DI and there was a high correlation (0.95) between them. We evaluateddrought status in the region using SPI, and after that analyzed SPI results with droughtevaluation indicators. The results show that the basin’s general trend is towardincreasing drought occurrence. The Urmia Lake water level is declining as well, andthis study also found that the wet stations’ proportion of drought is rising and that thedrought intensity in the basin has an upward trend. Also, some drought-affected stationshave a positive trend gradient. In general, the results can provide substantial informationfor future drought risk assessment and guidance to decision makers, ranging fromagricultural producers to policy makers from the local to national level.

Keywords:

Drought , drought evaluation indicators , DI , SPI , Urmia Lake basin