Acceleration of warming, deoxygenation and acidification in the Arabian Gulf driven by weakening of summer winds

The Arabian Gulf (AG) exports hypersaline, dense waters into the Sea of Oman (SOO), replaced by fresher inflowing surface waters from the Indian Ocean. We investigate the impact of recent AG warming on its exchange with the SOO and the implications this has on the AG biogeochemistry. Using an eddy-resolving hindcast model simulation, we analyze the hydrography and biogeochemistry of the AG and the SOO from 1980 to 2018. Our study reveals that changes in summer surface winds have accelerated AG warming and weakened it in the SOO, reducing the density gradient and water exchange between the two seas during late summer. This has led to nutrient buildup, increased productivity, and heightened deoxygenation and acidification in the AG. These findings underscore how subtle wind changes can exacerbate the vulnerability of marginal seas to climate change and stress the need to properly represent regional winds in global climate models.