Investigation of meteorological drought in Urmia using SPI under climate change scenarios (RCP)

Variations in frequency and intensity of drought have substantial impact on water resources and environment, which in turn are reflected on agriculture, society, and economy. The aim of this study is to investigate the effect of climate change on meteorological drought in Urmia. For this purpose, using rainfall data, the drought of the base period (1986-2005) and the future periods (2031-2050 and 2051-2070) were calculated for 3, 6, 12 and 24-months’ time scales in Urmia. Precipitation for future periods were determined using the CanESM2 Fifth Report Model and three Scenarios (RCP2.6, RCP4.5 and RCP8.5) and were downscaled using the SDSM model. Then the trend values of SPI in baseline and future periods were investigated using Mann-Kendall test. The study of precipitation changes showed that in the first future period, based on two scenarios RCP2.6 and RCP8.5, the average precipitation will increase, but in the second future period there is a very small decrease in precipitation. Also, SPI values on a long-term time scales indicate a higher severity of drought and among the studied scenarios, RCP8.5 shows more severe drought intensity than the base period compared to other scenarios. The results of trend analysis also show significant changes in SPI values in the reference period and future periods based on the RCP8.5 scenario.