The Evaluation of Climate Change Impact on Agricultural Drought by Soil Moisture Deficit Index Using Fifth Report Models and Scenarios

Soil moisture is a determinative parameter in many of the complex environmental processes and plays a decisive role in the occurrence of agricultural drought. So, in this study, based on estimated soil moisture data by SWAP model and Fifth Report Data of Climate Change, agricultural drought was determined by Soil Moisture Deficit Index for the upcoming period (2020-2039) for the wheat field of Faroub in Neyshabour. The climatic data were estimated using six models of GCM and two emission scenarios of 4.5 and 8.5 and were downscaled by LARS-WG model. Then the downscaled climatic data along with field, irrigation and soil data were entered into the SWAP model. Finally, using soil moisture data of 0-30 cm depth, agricultural drought was evaluated using SMDI index. The results showed that the minimum and maximum temperatures and precipitation in the upcoming period have increased compared to the base period and 8.5 scenario have estimated a higher temperature and lower rainfall than the 4.5 scenario. Also, the average SMDI in the upcoming period has increased relative to the base period for both scenarios. The certainty results of GCM models for estimation of SMDI index also showed that under the 4.5 scenario, the IPSL and MIROC models have the highest certainty and the Canesm2 model has the lowest certainty. Under the 8.5 scenario, MIROC model has the highest certainty and Ciromk-3.6 and GFDL models have the lowest certainty.