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Modeling El Niño and its tropical teleconnections during the last glacial‐interglacial cycle
Author(s) -
OttoBliesner Bette L.,
Brady Esther C.,
Shin SangIk,
Liu Zhengyu,
Shields Christine
Publication year - 2003
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 - 10.1029/2003gl018553
Subject(s) - climatology , last glacial maximum , teleconnection , interglacial , holocene , thermocline , walker circulation , geology , sea surface temperature , upwelling , glacial period , water cycle , oceanography , precipitation , environmental science , atmospheric sciences , geography , geomorphology , el niño southern oscillation , ecology , meteorology , biology
Simulations with the NCAR Climate System Model (CSM), a global, coupled ocean‐atmosphere‐sea ice model, for the last glacial‐interglacial cycle reproduce recent estimates, based on alkenones and Mg/Ca ratios, of sea surface temperature (SST) changes and gradients in the tropical Pacific and predict weaker El Niños/La Niñas compared to present for the Holocene and stronger El Niños/La Niñas for the Last Glacial Maximum (LGM). Changes for the LGM (Holocene) are traced to a weakening (strengthening) of the tropical Pacific zonal SST gradient, wind stresses, and upwelling and a sharpening (weakening) of the tropical thermocline. Results suggest that proxy evidence of weaker precipitation variability in New Guinea and Ecuador are explained not only by changes in El Niño/La Niña but also changes in the atmospheric circulation and hydrologic cycle.