The role of the Alaskan Stream in modulating the Bering Sea climate

Abstract

A numerical ocean circulation model with realistic topography, but with an idealized forcing that includes only lateral transports is used to study the role of the Alaskan Stream (AS) in modulating the Bering Sea (BS) variability. Sensitivity experiments, each one with a different strength of the AS transport reveal a nonlinear BS response. An increase of AS transport from 10 to 25 Sv causes warming (∼0.25°C mean, ∼0.5°C maximum) and sea level rise in the BS shelf due to increased transports of warmer Pacific waters through the eastern passages of the Aleutian Islands, but an increase of AS transport from 25 to 40 Sv had an opposite impact on the BS shelf with a slight cooling (∼-0.1°C mean, ∼-0.5°C maximum). As the AS transport increases, flows through passages farther downstream in the western Aleutian Islands are affected and the variability in the entire BS is reduced. Transport variations of ~0.1Sv in the Bering Strait are found to be correlated with mesoscale variations f the AS and associated transport variations in the Aleutian Islands passages. These results have important implications for understanding the observed variations in the Bering Strait and potential future climate variations in the Arctic Ocean. Copyright 2010 by the American Geophysical Union.