Spatio-Temporal Analysis of Changes in the Iranian Summer Subtropical High-Pressure System from a Climate Change Perspective

Climate change plays a significant role in altering the behavior of large-scale atmospheric systems, particularly the subtropical high-pressure systems relevant to the climate of Iran. This study investigates the impact of climate change on the subtropical high-pressure system over Iran by utilizing ERA5 reanalysis data and CORDEX projections. Focusing on future projections (2022–2063) under RCP4.5 and RCP8.5 scenarios, the analysis reveals substantial shifts in the position and intensity of the subtropical high when comparing the high-pressure center between currently observed data and the projected scenarios. The center of the high-pressure system exhibits a northward migration, particularly pronounced in August; a consistent upward trend in geopotential height, analyzed using the Kendall trend method, is observed, indicating a strengthening of the high-pressure system. This intensification leads to a westward and northward expansion of the summer high-pressure cell. Consequently, this study anticipates the emergence of more pronounced cyclonic circulations at higher latitudes (>38° N) in the future. These findings suggest that climate change will substantially alter the behavior of the subtropical high over Iran, impacting regional weather patterns and potentially leading to climate anomalies.