Climate Change Research

Climate Change Research

Projecting Aridity Changes in Iran Based on SSP Scenarios: A Climate Change Perspective

Document Type : Original Article

Authors
Mohsen Hamidian Pour 1
Halimah Shahzaei 2
1 Associate Professor, Depertment of Physical Geography, University of Sistan and Baluchistan, Zahedan, Iran
2 Master's student in Climatology, University of Sistan and Baluchestan, Zahedan, Iran
10.30488/ccr.2025.499536.1264
Abstract
This research investigated the spatio-temporal changes of Iran's climate aridity coefficient during the observed period (1976-2020) and its projection for the future period (2031-2050). To examine the aridity coefficient, precipitation and temperature data from 44 meteorological stations across the country during the base period of 1976-2014, outputs of SSP scenarios (SSP146, SSP246, and SSP585) from General Circulation Models (CMIP6 phase), and the de Martonne aridity index method were used. For the projection of precipitation and temperature data, and consequently the calculation of the aridity coefficient in the future period, the LARS-WG8 downscaling model was employed. To evaluate the temporal and spatial changes of the aridity coefficient, the non-parametric Mann-Kendall test and Sen's slope method were used. The results of the first part of the study, which examined the changes during the observed period, showed that the aridity coefficient had a decreasing trend between 1976 and 2020. This decreasing trend was more pronounced in areas with Mediterranean climates (-0.187) and humid regions (-0.102). Based on the outputs of the downscaled data and the scenarios used in the future period, the aridity trend varied and was mainly decreasing in all three scenarios (optimistic, pessimistic, and moderate). This indicates a trend towards a more continental climate, characterized by decreased humidity and increased temperature
Keywords
climate change
aridity coefficient
Downscaling
GCMs
SSP scenarios

Subjects

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