Cold season Arctic strong cyclones enhance Atlantification of the Arctic Ocean

Abstract

Abstract In recent years, as the Arctic Ocean’s warming trend has accelerated, there has been increasing attention on the process of Atlantification in the Arctic Ocean. This study focused on the Arctic Atlantic inflow zone (AAZ) as its research area. Multi-source reanalysis data and in-situ Argo float data were utilized to detect Arctic strong cyclones (ASCs) in the AAZ and analyze the resulting changes in the upper ocean. The findings reveal that during the cold season (October to March), influenced by ASCs’ intensity, frequency, tracks, and the concurrent weakening of ocean stratification, these cyclones can disrupt the cold halocline layer through mechanisms such as mixing and Ekman pumping. This process facilitates the transport of heat from the deep, warm and saline Atlantic Water within the ocean to the subsurface layers. Concurrently, ASCs during the cold season can enhance the process of Atlantification in the Arctic Ocean by intensifying the intrusion of the Barents Sea Branch. Additionally, the attenuation of oceanic stratification during ASCs is primarily driven by changes in salinity, particularly above the 100 m.