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Dynamical changes in the tropical Pacific warm pool and zonal SST gradient during the Pleistocene
Author(s) -
Dyez Kelsey A.,
Ravelo A. Christina
Publication year - 2014
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 - 10.1002/2014gl061639
Subject(s) - sea surface temperature , climatology , interglacial , glacial period , walker circulation , environmental science , pleistocene , tropics , radiative forcing , forcing (mathematics) , oceanography , geology , carbon dioxide in earth's atmosphere , atmospheric sciences , climate change , ecology , biology , paleontology , geomorphology
Abstract In the late Pleistocene, the atmospheric carbon dioxide concentration ( p CO 2 ) is thought to be a primary driving force for tropical sea surface temperature (SST) change because glacial‐interglacial changes in tropical Pacific SST covary with p CO 2 . However, if the regional radiative effects of p CO 2 were the only agent of change, tropical SST gradients should have remained similar as p CO 2 varied with time. Instead, a new record of SST from the west Pacific shows that tropical SST gradients were different, even reversed, in the past, suggesting an important role for dynamical circulation changes. Specifically, changes in the temperature of upwelled source water, in addition to local p CO 2 forcing, influenced tropical Pacific SST. These dynamical changes, rather than p CO 2 , may have shifted the background state of the tropics and even helped set the stage for the mid‐Pleistocene transition.