Zonal control on Holocene precipitation in northwestern Madagascar based on a stalagmite from Anjohibe

Robin R Dawson; Stephen J Burns; Benjamin H Tiger; David McGee; Peterson Faina; Nick Scroxton; Laurie R Godfrey; Lovasoa Ranivoharimanana

doi:10.1038/s41598-024-55909-6

Zonal control on Holocene precipitation in northwestern Madagascar based on a stalagmite from Anjohibe

Sci Rep. 2024 Mar 6;14(1):5496. doi: 10.1038/s41598-024-55909-6.

Authors

Robin R Dawson¹, Stephen J Burns², Benjamin H Tiger^{3

4}, David McGee³, Peterson Faina⁵, Nick Scroxton⁶, Laurie R Godfrey⁷, Lovasoa Ranivoharimanana⁸

Affiliations

¹ Department of Earth, Geographic and Climate Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA. rrdawson@umass.edu.
² Department of Earth, Geographic and Climate Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
³ Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
⁴ Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
⁵ The Climate School, Columbia University, New York, NY, 10025, USA.
⁶ Irish Climate Analysis and Research Units, Department of Geography, Maynooth University, Maynooth, Ireland.
⁷ Department of Anthropology, University of Massachusetts, Amherst, MA, 01003, USA.
⁸ Mention Bassins Sédimentaires, Evolution, Conservation, Faculté des Sciences, Université D'Antananarivo, Antananarivo, Madagascar.

Abstract

The Malagasy Summer Monsoon is an important part of the larger Indian Ocean and tropical monsoon region. As the effects of global warming play out, changes to precipitation in Madagascar will have important ramifications for the Malagasy people. To help understand how precipitation responds to climate changes we present a long-term Holocene speleothem record from Anjohibe, part of the Andranoboka cave system in northwestern Madagascar. To date, it is the most complete Holocene record from this region and sheds light on the nature of millennial and centennial precipitation changes in this region. We find that over the Holocene, precipitation in northwestern Madagascar is actually in phase with the Northern Hemisphere Asian monsoon on multi-millennial scales, but that during some shorter centennial-scale events such as the 8.2 ka event, Anjohibe exhibits an antiphase precipitation signal to the Northern Hemisphere. The ultimate driver of precipitation changes across the Holocene does not appear to be the meridional migration of the monsoon. Instead, zonal sea surface temperature gradients in the Indian Ocean seem to play a primary role in precipitation changes in northwestern Madagascar.

Abstract

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