Document Type : Research Paper
Authors
1 Post-doctoral researcher of Climatology, University of Mohaghegh Ardabili, Ardabil, Iran
2 Professor of Climatology, Department of Physical Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
Abstract
In this research, the drought situation of Aras Basin under the conditions of climate change has been investigated. For this purpose, simulated precipitation data of CNRM-CM6-1-HR model with high horizontal resolution (10 km) under SSP585 scenario during 76 years and 912 months of the future period (2100-2025) were used, and the SPI index was determined as a criterion for evaluating the drought situation. The monthly analysis of the future drought under the SSP585 scenario with the SPI index showed that the drought trend is decreasing in all stations except Jolfa station. Under the SSP585 scenario, the most severe drought of the period was simulated in Ardabil and Ahar in April 2094, in Jolfa in April 2094, in Parsabad in February 2028, in Khoi in September 2078 and in Mako in May 2080. On an annual scale, the frequency of drought in Mako, Jolfa, Parsabad, Khoi and Ardabil was calculated as 42, 41, 39, 36 and 34 years respectively. Spatial distribution of annual precipitation anomalies in Aras basin showed that the maximum of very severe drought and the minimum of very severe wets are located in the southeast of the basin (Ardabil station), while the maximum core of extreme wets and the minimum core of extreme drought are concentrated in the southwest of the basin. On a monthly scale, the core of maximum and minimum frequency of positive anomalies is mainly located in the western half of the basin. On an annual scale, the largest increase in the estimated positive precipitation anomalies was related to Ardabil, Parsabad and Ahar, and the largest decrease in negative anomalies was related to Ahar, Khoy and Ardabil. On a monthly scale, the maximum decrease in negative anomaly is related to Parsabad and the maximum percentage increase in positive anomaly is related to Jolfa.
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