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Tropical Atlantic climate response to low‐latitude and extratropical sea‐surface temperature: A Little Ice Age perspective
Author(s) -
Saenger Casey,
Chang Ping,
Ji Link,
Oppo Delia W.,
Cohen Anne L.
Publication year - 2009
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 - 10.1029/2009gl038677
Subject(s) - intertropical convergence zone , extratropical cyclone , climatology , sea surface temperature , paleoclimatology , latitude , environmental science , geology , atlantic multidecadal oscillation , convergence zone , precipitation , atmospheric sciences , climate change , oceanography , geography , meteorology , geodesy
Proxy reconstructions and model simulations suggest that steeper interhemispheric sea surface temperature (SST) gradients lead to southerly Intertropical Convergence Zone (ITCZ) migrations during periods of North Atlantic cooling, the most recent of which was the Little Ice Age (LIA; ∼100–450 yBP). Evidence suggesting low‐latitude Atlantic cooling during the LIA was relatively small (<1°C) raises the possibility that the ITCZ may have responded to a hemispheric SST gradient originating in the extratropics. We use an atmospheric general circulation model (AGCM) to investigate the relative influence of low‐latitude and extratropical SSTs on the meridional position of the ITCZ. Our results suggest that the ITCZ responds primarily to local, low‐latitude SST anomalies and that small cool anomalies (<0.5°C) can reproduce the LIA precipitation pattern suggested by paleoclimate proxies. Conversely, even large extratropical cooling does not significantly impact low‐latitude hydrology in the absence of ocean‐atmosphere interaction.