Drought monitoring in Urmia Lake by fuzzy index

Drought is a climate phenomenon with a lack of moisture and rainfall compared to normal conditions. This phenomenon strongly affects all aspects of human activity. In this Article, were discussed the drought situation in Urmia Lake using MATLAB software and system capabilities combined indicators SEPI on two-time scales 6 and 12 months. Therefore was used climate data of temperature and precipitation for 5 synoptic stations basin of Lake Urmia (Tabriz, Maragheh, Urmia, Saghez, and Mahabad). Results indicated that SEPI index show features of SPI and SEPI index. As well as it enters temperatures as a powerful factor in the drought severity in order to the investigation of the drought conditions; So SEPI drought index is better than the SPI for the study of drought. Drought studies on SEPI index indicated that drought trend in Urmia Lake Basin is increasing. The temperature has an increasing trend with more intensity. The longest duration of drought in the basin of Lake Urmia is in Urmia station on a scale of 6 months from May 2005 to November 2006 for 19 months. The highest percentage of drought observed in Urmia and the lowest percentage in Mahabad stations.