The Beaufort Gyre (BG) in the Arctic Ocean has experienced rapid changes in losing extensive amounts of sea-ice and undergoing freshening over the past few decades. In this study, we highlight important recent changes in BG’s surface circulation, and its impact on freshwater (FW) fluxes and freshwater content (FWC) and draw attention to the critical importance of continuous monitoring of BG dynamics. Using satellite observations of the upper ocean state and ocean and atmospheric reanalysis, here we attempt to understand the anomalous behavior of BG dynamics over the past few decades. In recent years, atmospheric forcings increasingly influenced important judications for the BG's FWC and surface FW fluxes. In 2007, there was a large cell of high atmospheric pressure that induced considerable sea-ice loss, and increased sea surface temperatures (SSTs), and absolute dynamic topography (ADT). This resulted in increased geostrophic winds, pushing the FW into the BG, yielding a considerable augmented FWC. In early 2016, a wave of heat culminated in the Arctic’s troposphere resulting in a strong rapid tropospheric warming (RTW) event. We found that this RTW event demonstrated considerable influence on the pathways of FW, reversing the Bering Strait’s flow and increasing the intensity of both the Bering Strait and Fram Strait throughflow. This has exceedingly important implications for global climate, as FW release into the subpolar regions can impact large-scale overturning of ocean currents. We also found that in the months following the RTW events, the Pacific Winter Water (PWW) layer increases in thickness, most likely due to the increased FW in the BG, indicating BG freshening. These findings underscore the need for sustained monitoring efforts of the BG dynamics that affect the regional as well as global ocean and atmospheric circulation.
Gregory et al. (Fri,) studied this question.