Atmospheric Controls on Upwelling in the Pacific Sector of the Arctic Ocean

Abstract:

Wind-driven upwelling occurs throughout the year along the shelfbreak
of the Beaufort and Chukchi Seas in the western Arctic Ocean. This
drives significant shelf-basin exchange of heat, freshwater,
nutrients, carbon, and zooplankton, which affects the regional
ecosystem. Here we explore different aspects of the atmospheric
forcing, together with the contributing influences of orography,
sea-ice, and ocean dynamics that dictate the occurrence and strength
of the upwelling. The local winds are dictated primarily by two
Centers of Action, the Beaufort High and Aleutian Low, both of which
vary significantly throughout the year and on interannual
timescales. The precise trajectories of the individual Aleutian low
pressure systems, influenced by the high orography of Alaska and
Canada, are particularly important in determining the strength of the
upwelling and the character of the oceanographic response. In
addition, the presence of sea-ice strongly modulates the water column
response. Over the past decade the prevailing easterly winds have
increased, which suggests that future upwelling may no longer be
associated only with storm events. This has significant
oceanographic ramifications.