Fast and slow responses of the North Pacific mode water and Subtropical Countercurrent to global warming

TitleFast and slow responses of the North Pacific mode water and Subtropical Countercurrent to global warming
Publication TypeJournal Article
Year of Publication2013
AuthorsXu LX, Xie SP, Liu QY
JournalJournal of Ocean University of China
Volume12
Pagination216-221
Date Published2013/06
Type of ArticleArticle
ISBN Number1672-5182
Accession NumberWOS:000318300200004
KeywordsCMIP5; fast and slow response; gcm; mode water; radiative forcing; STCC; ventilated thermocline
Abstract

Six coupled general circulation models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) are employed for examining the full evolution of the North Pacific mode water and Subtropical Countercurrent (STCC) under global warming over 400 years following the Representative Concentration Pathways (RCP) 4.5. The mode water and STCC first show a sharp weakening trend when the radiative forcing increases, but then reverse to a slow strengthening trend of smaller magnitude after the radiative forcing is stablized. As the radiative forcing increases during the 21st century, the ocean warming is surface-intensified and decreases with depth, strengthening the upper ocean's stratification and becoming unfavorable for the mode water formation. Moving southward in the subtropical gyre, the shrinking mode water decelerates the STCC to the south. After the radiative forcing is stabilized in the 2070s, the subsequent warming is greater at the subsurface than at the sea surface, destabilizing the upper ocean and becoming favorable for the mode water formation. As a result, the mode water and STCC recover gradually after the radiative forcing is stabilized.

DOI10.1007/s11802-013-2189-6