Intensification of marine heatwaves and their climate drivers in the Arabian Gulf

Abstract

Marine heatwaves (MHWs) are extreme sea surface temperature (SST) phenomena that can profoundly impact marine ecosystems but remain largely unexplored in the Arabian Gulf. We use a high resolution satellite SST and atmospheric reanalysis datasets to perform an extensive study of spatial and temporal variations of MHWs and their potential driving factors. Significant positive trends in MHW days, duration, and frequency are observed, particularly in the southeastern Gulf and the Sea of Oman during the summer. The Gulf experienced an increase of 0.6 MHW days/yr with an increasing intensity of C/yr in summer while summer SST also shows an increase of C/yr, indicating a notable warming trend. The first two EOF modes explain 80% of MHW variability, showing a Gulf-wide pattern in the first mode (62%) and contrasting Gulf versus Sea of Oman behavior in the second (18%), reflecting different underlying physical processes. Weakened Shamal winds and strengthened Kaus winds are observed during major MHW years, suggesting their potential influence on surface warming. MHWs often coincide with negative wind stress curl in upwelling zones and reduced latent heat loss, indicating weakened ocean cooling. While positive mean sea level (MSL) pressure anomalies are frequently observed, their inconsistency suggests that multiple ocean–atmosphere processes contribute to MHW development. Understanding these trends helps predict future extremes and mitigate their impacts, contributing to global efforts to protect marine ecosystems and coastal communities in a warming world.