Analysis of Meteorological Drought Situation of Neyshabour Station Using Data of the Fifth Report of Climate Change

Drought is a crawling environmental phenomenon that has a major impact on the economy, agriculture and society. This phenomenon is more pronounced in the eastern, central and southern parts of Iran due to its dry and semi-arid climate. According to the fact that the meteorological drought starts by the rainfall shortage, so, the standard precipitation index (SPI) with different time scales (3, 6 and 12 months) are obtained for the Neyshabour synoptic station using the fifth report data. Precipitation synthetic data were determined using the 6 models and the two RCP4.5 and RCP8.5 emission scenarios of the LARS-WG downscaling model. Finally, using the rainfall data, the value of SPI drought index for the base period (1992-2011) and the future period (2020-2039) were calculated in the three-time scales. The results showed that the highest and lowest daily precipitation mean values in the yearly scale for the future period under influence of the RCP 4.5 scenario the Canesm2 and MIROC models and under influenced of the RCP8.5 scenario belonged to the GISS-ES-R and Csiromk-3.6 models, respectively. The SPI values at 12-month time scale showed more drought intensity than the 3 and 6-month periods. The results also showed that under the RCP4.5 scenario the MIROC and GISS-ES-R models and under the RCP8.5 scenario the Canesm2 and MIROC models estimated a greater number of dry years.