The Persian Gulf and Oman Sea: Climate variability and trends inferred from satellite observations

Abstract

The warming trend in the Indian Ocean since the mid-20th century, with a strong signature over the Persian Gulf and Oman Sea, has been recognized as indisputable evidence of anthropogenic global warming. Further amplified warming is predicted for the coming decades. Therefore, a climatological assessment over recent decades is essential for mitigating environmental disasters. A comprehensive overview of the climate mean-state and variability across this region is provided using satellite-derived sea surface temperature (SST), surface wind, and Chlorophyll-a concentration (Chl-a). With more signature over the northwest and center of the Gulf, SST and wind are closely connected in which summers with intensified winds are not dramatically warm. It supports the notion that summertime northwesterly winds in the Gulf protect marine ecosystems from severe warm anomalies. Except in the south of the Gulf, the SST and Chl-a are anti-correlated. Our finding suggests that the Indian Ocean Dipole cycles considerably affect SST and winds over the western and central portions of the Gulf and the southern sector of the Oman Sea. Our evaluation of regional SST trends indicates a heterogeneous regional warming, which implies a significant contribution of small-scale processes in SST changes. This widens the uncertainty in regional climate projections. Furthermore, locally measured temperatures in several intertidal zones depict pronounced diurnal variations missing in satellite images, highlighting the need for an observation network to assess the localized impacts of global warming on the intertidal biota.