The effect of Arctic freshwater pathways on North Atlantic convection and the Atlantic Meridional Overturning Circulation

TitleThe effect of Arctic freshwater pathways on North Atlantic convection and the Atlantic Meridional Overturning Circulation
Publication TypeJournal Article
Year of Publication2018
AuthorsWang H, Legg S., Hallberg R.
JournalJournal of Climate
Volume31
Pagination5165-5188
Date Published2018/07
Type of ArticleArticle
ISBN Number0894-8755
Accession NumberWOS:000437827700012
Keywordsbering strait; canadian archipelago; characteristics; climate-change; Deep convection; global ocean; labrador sea; lancaster sound; Meteorology & Atmospheric Sciences; part i; simulation; thermohaline circulation
Abstract

This study examines the relative roles of the Arctic freshwater exported via different pathways on deep convection in the North Atlantic and the Atlantic meridional overturning circulation (AMOC). Deep water feeding the lower branch of the AMOC is formed in several North Atlantic marginal seas, including the Labrador Sea, Irminger Sea, and the Nordic seas, where deep convection can potentially be inhibited by surface freshwater exported from the Arctic. The sensitivity of the AMOC and North Atlantic to two major freshwater pathways on either side of Greenland is studied using numerical experiments. Freshwater export is rerouted in global coupled climate models by blocking and expanding the channels along the two routes. The sensitivity experiments are performed in two sets of models (CM2G and CM2M) with different control simulation climatology for comparison. Freshwater via the route east of Greenland is found to have a larger direct impact on Labrador Sea convection. In response to the changes of freshwater route, North Atlantic convection outside of the Labrador Sea changes in the opposite sense to the Labrador Sea. The response of the AMOC is found to be sensitive to both the model formulation and mean-state climate.

DOI10.1175/jcli-d-17-0629.1
Student Publication: 
No