6533b832fe1ef96bd129abc8
RESEARCH PRODUCT
21. Abrupt change of El Niño activity off Peru during stage MIS 5e-d
Frank SirockoWolf-christian DulloRein BertAndreas LückgeAnja WolfLutz Reinhardtsubject
Marine isotope stagegeographygeography.geographical_feature_categoryOceanographyContinental shelfClimatologyInterglacialFluxGlacial periodIce sheetHoloceneGeologyLatitudedescription
Abstract High-resolution proxy data for El Nino variability during the last glacial cycle were derived from a laminated marine sediment core from a region whose climatology and oceanography is strongly affected by ENSO variability. The proxies used are the seasurface temperature and the lithic flux from the continent onto the continental shelf that is largely controlled by the river flood discharge after strong El Nino rainfall in northern and northern central Peru. The focus of this paper is on an abrupt, possibly orbitally driven change of El Nino activity within marine isotope stage 5e. A similar sharp decline of El Nino activity is also observed during the middle of the Holocene interglacial 8 kyr ago. Thus, the major last interglacial and the major Holocene periods of El Nino weakness as documented in the sediments commenced during times with very similar seasonal insolation maximum. Whereas El Nino activity strengthened during the late Holocene with more favourable seasonal heating, El Nino activity did not recover during the very early glacial period with even more favourable insolation conditions but changed boundary conditions. Strong El Nino activity during marine isotope stage 5d was postulated after experiments with the Zebiak and Cane ENSO model and so considered as a major source of moisture excess for the build-up of North American ice sheets. The data from Peru reveal that modelled strong El Nino activity did not occur in reality and was thus not able to supply excessive moisture to the mid- and higher latitudes for the growth of ice sheets.
year | journal | country | edition | language |
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2007-01-01 |