Impacts of Atmospheric Near-Surface Stability on the Arctic Summer Air-Sea Heat Budget Using Uncrewed Surface Vehicles

Abstract

The atmospheric marine boundary layer (AMBL) plays a crucial role in regulating air-sea interactions and influencing the climate system, particularly in the Arctic due to its high sensitivity to global warming. This study utilizes five years (2018–2022) of saildrone data from the Bering-Chukchi-Beaufort Seas to analyze atmospheric near-surface stability and air-sea turbulent heat fluxes during the Arctic summer. By applying Monin-Obukhov similarity theory, we investigate the temporal variability and mechanisms that influence AMBL stability. Our findings reveal two distinct regimes of stable and unstable conditions in two contrasting years of 2020 and 2022. In 2020, cold air advection driven by northerly winds consistently destabilizes the AMBL, leading to increased oceanic heat loss. In 2022, however, southerly winds and warm air advection stabilize the AMBL, suppressing air-sea heat exchanges. The temporal variation of turbulent heat fluxes is primarily driven by air-sea temperature differences, with the magnitude of wind speed and its temperature covariance serving as secondary factors. We also show the importance of skin temperature measurements from saildrones for improving estimates of turbulent heat fluxes. These insights enhance our understanding of Arctic air-sea interactions and inform climate models, underscoring the need for high-resolution observations in polar regions and the improvement of bulk flux parameterization for stable AMBL.