Evaluation and Comparison of Drought in West Azerbaijan Using the SPI, CZI, PNI Iindices and Geographic Information System (GIS)

Recognizing and studying the drought phenomenon with regard to the affecting factors led to better understanding of this phenomenon and paved the way for short-term and long-term planning in relation to encountering, controlling and predicting of this phenomenon.Since to determine the severity, duration, and frequency of drought, is need to determine the drought by using indicators, drought monitoring is essential and researchers have always followed the use of indicators for drought monitoring as a management and planning tool. Drought monitoring is one of the prime factors in drought management. Monitoring systems have important roles in creating the drought plans and its management. Therefore, due to this importance  and taking into account the ecological and geographical conditions of Lake Urmia during recent years, the study and monitoring of drought for the above area is necessary. Therefore, the purpose of this study was to investigate the drought characteristics and calculate the three (SPI, PNI, CZI) drought indexes and comparing their efficiency and accuracy in the Western Azerbaijan province, as well as evaluating the time trends of their changes over the entire province.