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The post‐2002 global surface warming slowdown caused by the subtropical Southern Ocean heating acceleration
Author(s) -
Oka A.,
Watanabe M.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl072184
Subject(s) - slowdown , downwelling , ekman transport , global warming , climatology , subtropics , environmental science , sea surface temperature , ocean heat content , wind stress , effects of global warming on oceans , oceanography , climate change , atmospheric sciences , geology , upwelling , economics , fishery , economic growth , biology
The warming rate of global mean surface temperature slowed down during 1998–2012. Previous studies pointed out role of increasing ocean heat uptake during this global warming slowdown, but its mechanism remains under discussion. Our numerical simulations, in which wind stress anomaly in the equatorial Pacific is imposed from reanalysis data, suggest that subsurface warming in the equatorial Pacific took place during initial phase of the global warming slowdown (1998–2002), as previously reported. It is newly clarified that the Ekman transport from tropics to subtropics is enhanced during the later phase of the slowdown (after 2002) and enhanced subtropical Ekman downwelling causes accelerated heat storage below depth of 700 m in the subtropical Southern Ocean, leading to the post‐2002 global warming slowdown. Observational data of ocean temperature also support this scenario. This study provides clear evidence that deeper parts of the Southern Ocean play a critical role in the post‐2002 warming slowdown.