AUTHOR=Kawai Yoshimi 

TITLE=Low-Level Atmospheric Responses to the Sea Surface Temperature Fronts in the Chukchi and Bering Seas

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2021.598981

DOI=10.3389/fmars.2021.598981

ISSN=2296-7745

ABSTRACT=Atmospheric responses to sea surface temperature (SST) fronts related to western boundary currents have been extensively analyzed over the last two decades. However, the organized near-surface response to SST, which refers to the temperature of open water or sea ice in this study, at higher latitudes where sea ice exists has been rarely investigated due to the difficulties of observations. Here, 32 years of high-resolution atmospheric reanalysis data are analyzed to determine the atmospheric effects of SST fronts in the Bering Sea and Chukchi Sea. In the Chukchi Sea, the convergence of 10-m-high wind increases in October and November, when the horizontal gradient and Laplacian of SST become noticeable. On the other hand, an SST contrast between the continental shelf and the southwestern deep basin develops in winter in the Bering Sea. In both seas, the spatial distribution of surface wind convergence and the Laplacians of SST and sea level pressure agree well with each other, demonstrating the pressure adjustment mechanism. The vertical mixing mechanism is also confirmed in both seas. Ascending motion and diabatic heating develop over the Chukchi Sea in late autumn, but are confined to the lower troposphere. Turbulent heat fluxes at the surface become especially large in this season, resulting in an increase of diabatic heating and low-level clouds. Low-level clouds and downward shortwave radiation exhibit contrasting behavior across the shelf break in the Bering Sea that corresponds to the SST distribution, which is regulated by the bottom topography.