Relative contributions of local heat storage and ocean heat transport to cold‐season Arctic Ocean surface energy fluxes in CMIP6 models

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Hajjar, Khaled al, Salzmann, Marc
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons, Ltd 2023
• Subjects: ddc:551.46; Arctic amplification; CMIP6; heat storage and transport; Arctic; Arctic Ocean; albedo
• Online Access: https://doi.org/10.1002/qj.4496; http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11651

Abstract The Arctic near‐surface air temperature increases most strongly during the cold season, and ocean heat storage has often been cited as a crucial component in linking the ice‐albedo radiative feedback, which is active in summer, and near‐surface air temperature increase in winter, when the lapse rate feedback contributes to Arctic warming. Here, we first estimate how much local heat storage and ocean heat transport contribute to net surface energy fluxes on a seasonal scale in CMIP6 models. We then compare contributions in a base state under weak anthropogenic forcing to a near‐present‐day state in which significant Arctic amplification is simulated. Our analysis indicates that, in a few regions, ocean heat transport plays a larger role for cold‐season net surface energy fluxes compared with local heat storage. Analyzing differences between past and near‐present‐day conditions suggests that the lapse rate feedback, which mainly acts during the cold season in warm water inflow regions, may be more strongly influenced than previously thought by increased ocean heat transport from lower latitudes. Arctic Ocean net upward surface energy fluxes in the cold season were decomposed into contributions from local heat storage (yellow, see schematic) and ocean heat transport (red). Our analysis of CMIP6 model output suggests that, in a few inflow regions, ocean heat transport contributes more to cold‐season net surface energy fluxes compared with local heat storage. In parts of these inflow regions, the relative contribution of ocean heat transport increased with time. <graphic position="anchor" id="jats-graphic-1" xlink:href="urn:x-wiley:00359009:media:qj4496:qj4496-toc-0001"> </graphic> Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659 https://esgf-node.llnl.gov/projects/cmip6/ https://nsidc.org/data/g10010