Dynamics of the Southwest Asia Anticyclone: Linking Core Migration and Intensification to Precipitation Variability

The Southwest Asia Anticyclone (SWAA) plays a pivotal role in governing the regional precipitation regime. This study analyzes the structure and spatiotemporal variability of the SWAA core at the 850, 700, and 500 hPa levels, and its relationship with precipitation across Southwest Asia. Monthly precipitation and geopotential height (HGT) data were obtained from ERA5 reanalysis with a 0.25° spatial resolution over 1940–2023. The results showed that in September the SWAA core migrates from northwestern and western Saudi Arabia, shifting southward during colder periods and retreating landward in warmer periods. At 850 hPa, the core is absent during June–August, while at 700 hPa it is positioned over the southeastern Caspian Sea. The SWAA has intensified in recent decades, and its directional shifts exert a marked influence on precipitation variability: northeastward, eastward, southeastward, and southward displacements enhance rainfall, whereas northward, northwestward, and westward movements suppress it. Overall, the intensity and positioning of the SWAA are strongly linked to precipitation patterns in Southwest Asia. These findings contribute to refining precipitation and climate projections and offer practical implications for water resource management and agricultural planning in the region.