Local and Remote Sea-Surface Temperature Forcing of Extreme Humid-Heat in the Coastal Arabian Peninsula

Humid-heat stress is rising rapidly across the Arabian Peninsula (AP), where sea-surface temperatures (SSTs) strongly modulate both the magnitude and spatial expression of extreme humid-heat stress. Although local SSTs in adjacent basins are known to intensify boundary-layer moisture and elevate coastal humid-heat, the degree to which SST anomalies—both locally and remotely forced—independently influence temperature and humidity remains poorly understood. In particular, it is not yet understood how large-scale teleconnections such as the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) shape the occurrence and severity of humid-heat extremes in the AP, nor how these modes interact with local SST forcing. Here, we quantify how local and teleconnected SST anomalies independently and jointly influence present and future humid-heat extremes, characterized by wet-bulb temperature, heat index, and the humidity–temperature partitioning metric stickiness, across five major AP coastal cities (Doha, Dubai, Jeddah, Aden, and Muscat). We employ a hierarchical Bayesian peak-over-threshold (POT) framework using a generalized Pareto likelihood applied to the 95th-percentile threshold of daily humid-heat metrics. This structure enables us to:

• isolate the sensitivity of extreme humid-heat to ENSO and IOD phases;
• assess whether ENSO–IOD combinations amplify or dampen AP humid-heat risk; and
• separate humidity-driven vs. temperature-driven contributions to extremes. 

After establishing the observed relationships, we perturb the model with scenarios of increased local SSTs (+1°C, +2°C, +3°C, +4°C) in each adjacent basin to evaluate how direct ocean warming may alter extreme humid-heat distributions in coming decades. These experiments provide a mechanistic basis for attributing humid-heat amplification to specific SST pathways and for estimating the compound impacts of global teleconnections and regional warming on future coastal risk. Expected findings include (i) strong city-specific variability in ENSO and IOD influence, (ii) robust humidity-driven amplification under positive ENSO/IOD phases, and (iii) nonlinear increases in extreme humid-heat under uniform local SST warming. Together, these results establish a unified Bayesian framework for attributing and projecting SST-driven humid-heat risk across one of the world’s fastest-warming coastal regions.