Distribution and Characteristics of the Subsurface Eddies in the Aleutian Basin, Bering Sea

Subsurface eddies, characterized by their cores located within or below the pycnocline, can transport materials over long distances in the ocean's interior. Observations of these eddies are sparse, limiting our understanding of their regional distribution and detailed horizontal structures, particularly in high-latitude areas. The Bering Sea, situated in the subarctic region, is among the world's most productive areas and significantly influences the Arctic Ocean's state, thereby impacting climate change. In this study, we utilize ultrahigh resolution (approximately 10 m) data to investigate the distribution and characteristics of subsurface eddies in the Aleutian Basin, Bering Sea. We detected 44 subsurface eddies in 13 survey transects and analyzed their morphological and hydrographic characteristics, spatial distribution, propagation, and transport. The results show that the average core radius of the subsurface eddies is about 11.62 km and they exhibit complex structures in both the core and flank regions. The dichothermal layer cold-core eddies are prevalent in the deep-water region of the Bering Sea, contributing approximately 1.76 Sv poleward and westward transport in the subsurface layer. This is the first three-dimensional depiction of subsurface eddies in the Bering Sea, revealing that the prevalence of subsurface eddies in the Bering Sea may have been negligent, with significant implications for the hydrographic and biogeochemical properties of both the Bering Sea and the Arctic Ocean. More detailed comprehensive and long-term observations should be made to assess the global impact of subsurface eddies in the future.