Characterizing the Role of Atmospheric Circulation in Bering Sea Thermal Variability

The Bering Sea is experiencing accelerated rates of change relative to the rest of the globe, and has been subject to multiple instances of historic climate extremes in recent years. The region has been particularly affected by the near global increase in marine heatwaves, a trend that is projected to amplify under continued climate change. The role of air-sea coupling in driving amplified polar climate variability remains poorly quantified, largely due to a lack of observations of key variables describing these interactions and their role in climate variability. Our work seeks to address these open questions through an integrated analysis approach that leverages the NASA/JPL ECCO Ocean State Estimate and the ECMWF ERA5 fields to understand the impact of high-latitude air-sea interactions on the physical state of the Bering Sea.

In this work, we show that variability in air-sea coupling is a dominant factor in driving Bering Sea upper ocean temperature anomalies. We characterize the relationship between the atmospheric state and air-sea heat flux variability, and investigate the seasonal evolution of the heat flux terms and their influence on the annual heating cycle of the Bering Sea. Furthermore, we show strong evidence that atmospheric circulation, specifically the surface winds, air temperature, clouds, and humidity, drive much of the Bering Sea upper ocean temperature variability through mediation of the surface heat fluxes. We emphasize the recent decade (2010-onward), a period coincident with intense regional climate extremes, including record warm ocean temperatures, multiple years of historically low sea ice extent, and an increase in surface heat exchange variability.

Our results advance fundamental understanding of the role that the large-scale atmosphere plays in the thermal state of the Bering Sea. They highlight the necessity of understanding how future climate change may alter air-sea interactions in the Bering Sea, in order to better understand and predict their ecosystem impacts. Finally, the results of this work contribute to the characterization of the spatial and temporal variability of high-latitude coupled processes, thereby guiding the observational and modeling advancements that are essential for monitoring and predicting regional climate.