Mesoscale circulation in the Alaskan Stream area

TL;DR

This study analyzes mesoscale circulation and transport pathways of the Alaskan Stream in the North Pacific and Bering Sea, linking mesoscale eddy activity and wind stress curl to biological productivity and salmon catch.

Contribution

It demonstrates the connection between mesoscale eddy activity, wind stress curl, and biological/ecological outcomes in the Alaskan Stream region using altimetry-based Lagrangian maps.

Findings

Eddy activity correlates with wind stress curl in winter.

Chlorophyll a concentration relates to wind stress curl in late winter.

Mesoscale dynamics influence biomass and salmon abundance.

Abstract

The Alaskan Stream is the northern boundary current in the subarctic North Pacific. This area is characterized by significant temperature, salinity and density differences between coastal and open-ocean waters and strong mesoscale dynamics. In this paper we demonstrate the transport pathways of Alaskan Stream water in the eastern subarctic Pacific and the eastern Bering Sea from October 1, 1994 to September 12, 2016 with the help of altimetry-based Lagrangian maps. A mesoscale eddy activity along the shelf-deep basin boundaries in the Alaskan Stream region and the eastern Bering Sea is shown to be related with the wind stress curl in the northern North Pacific in winter. A significant correlation is found between the concentration of chlorophyll a in the Alaskan Stream area and eastern Bering Sea in August - September and the wind stress curl in the northern North Pacific in November - March. The mesoscale dynamics, forced by the wind stress curl in winter, may determine not only lower-trophic-level organism biomass but also salmon abundance/catch in the study area.