Investigating the 8.2 ka event in northwestern Madagascar: insight from data–model comparisons

Voarintsoa, Ny Riavo G; Matero, Ilkka SO; Railsback, L Bruce; Gregoire, Lauren J; Tindall, Julia; Sime, Louise ORCID: https://orcid.org/0000-0002-9093-7926; Cheng, Hai; Edwards, R Lawrence; Brook, George A; Kathayat, Gayatri; Li, Xianglei; Rakotondrazafy, Amos Fety Michel; Razanatseheno, Marie Olga Madison. 2019 Investigating the 8.2 ka event in northwestern Madagascar: insight from data–model comparisons. Quaternary Science Reviews, 204. 172-186. https://doi.org/10.1016/j.quascirev.2018.11.030

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Official URL: https://doi.org/10.1016/j.quascirev.2018.11.030

Abstract/Summary

The 8.2 ka event is a well-known cooling event in the Northern Hemisphere, but is poorly understood in Madagascar. Here, we compare paleoclimate data and outputs from paleoclimate simulations to better understand it. Records from Madagascar suggest two distinct sub-events (8.3 ka and 8.2 ka), that seem to correlate with records from northern high latitude. This could indicate causal relationships via changes in the Atlantic Meridional Overturning Circulation (AMOC) with changes in moisture source's d18O, and changes in the mean position of the Inter-Tropical Convergence Zone (ITCZ), as climate modelling suggests. These two sub-events are also apparent in other terrestrial records, but the climatic signals are different. The prominent 8.2 ka sub-event records a clear antiphase relationship between the northern and southern hemisphere monsoons, whereas such relationship is less evident during the first 8.3 ka sub-event. Data-model comparison have also shown a mismatch between the paleoclimate data and the model outputs, the causes of which are more or less understood and may lie in the proxies, in the model, or in both data and model. Knowing that paleoclimate proxies and climate models produce different sets of variables, further research is needed to improve the data-model comparison approach, so that both paleoclimate data and paleoclimate models will better predict the likely climate status of a region during a specified time in the past with minimal uncertainties.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.quascirev.2018.11.030
ISSN:	0277-3791
Additional Keywords:	Holocene, Speleothems, Stable isotopes, ITCZ-Monsoon, Madagascar, 8.2 ka event, Paleoclimate modeling, Data-model comparisons, AMOC
Date made live:	11 Dec 2018 11:00 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/521730

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.quascirev.2018.11.030

ISSN:

0277-3791

Additional Keywords:

Holocene, Speleothems, Stable isotopes, ITCZ-Monsoon, Madagascar, 8.2 ka event, Paleoclimate modeling, Data-model comparisons, AMOC

Date made live:

11 Dec 2018 11:00 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/521730