Reduced El Nino-Southern Oscillation during the last glacial maximum

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doi: 10.1126/science.1258437
Author(s): Ford, Heather L.; Ravelo, A. Christina; Polissar, Pratigya J.
Author Affiliation(s): Primary:
University of California, Santa Cruz, Ocean Sciences Department, Santa Cruz, CA, United States
Other:
Lamont-Doherty Earth Observatory, United States
Volume Title: Science
Source: Science, 347(6219), p.255-258. Publisher: American Association for the Advancement of Science, Washington, DC, United States. ISSN: 0036-8075 CODEN: SCIEAS
Note: In English. 32 refs.; illus., incl. sketch maps
Summary: El Nino-Southern Oscillation (ENSO) is a major source of global interannual variability, but its response to climate change is uncertain. Paleoclimate records from the Last Glacial Maximum (LGM) provide insight into ENSO behavior when global boundary conditions (ice sheet extent, atmospheric partial pressure of CO2) were different from those today. In this work, we reconstruct LGM temperature variability at equatorial Pacific sites using measurements of individual planktonic foraminifera shells. A deep equatorial thermocline altered the dynamics in the eastern equatorial cold tongue, resulting in reduced ENSO variability during the LGM compared to the Late Holocene. These results suggest that ENSO was not tied directly to the east-west temperature gradient, as previously suggested. Rather, the thermocline of the eastern equatorial Pacific played a decisive role in the ENSO response to LGM climate.
Year of Publication: 2015
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Biostratigraphy; Carbon dioxide; Cenozoic; East Pacific; El Nino Southern Oscillation; Equatorial Pacific; Foraminifera; Holocene; Invertebrata; Last glacial maximum; Leg 130; Leg 138; Microfossils; North Pacific; Northeast Pacific; Northwest Pacific; ODP Site 806; ODP Site 849; Ocean Drilling Program; Ontong Java Plateau; Pacific Ocean; Paleoclimatology; Pleistocene; Protista; Quaternary; Sea-surface temperature; Seasonal variations; Upper Holocene; Upper Pleistocene; West Pacific
Coordinates: N001058 N001100 W1103110 W1103111
N001906 N001907 E1592142 E1592140
Record ID: 2015035960
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.