A 18,000 yr record of tropical land temperature, convective activity and rainfall seasonality from the maritime continent

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Authors

Rienk H. Smittenberg , Kweku A. Yamoah , Akkaneewut Chabangborn , Sakonvan Chawchai , Frederik Schenk, Minna Minna Väliranta , Barbara Wohlfarth 

Abstract

The maritime continent exports an enormous amount of (latent) heat and moisture to the rest of the globe via deep atmospheric convection. How this export has changed through time under evolving boundary conditions, including the inundation of former Sundaland, is critical for the understanding of global climate dynamics. Given its size, relatively few high-resolution and continuous records exist of past hydroclimate, while terrestrial paleotemperature records are still completely absent from the region. In this study we present a 18,000-year multi-proxy record obtained from a lake sediment at the NW corner of former Sundaland. We found that rainfall seasonality was very important over the entire deglacial period, evidenced by biomass burning and C4 vegetation, despite rising atmospheric CO2 levels and increasing humidity that normally promotes C3 rainforests. The strong seasonality was reduced only upon ongoing inundation of Sundaland, with a clear inflection point around the Older Dryas event (13.8 ka BP), indicating a distinct system change. Land temperatures during the last stadial periods were 5°C colder than today’s 27°C. Temperatures rose gradually during the early Holocene to reach 29°C between 7-2 ka BP, accompanied by increasing convection, both driven by insolation power during the wet season. Convection decreased with lowering wet-season (autumn) insolation during the Meghalayan period, concurrent with the known increase of ENSO variability and Northern Hemisphere climate cooling and drying. Our results provide further insight in the role of Sundaland - turned maritime continent for the global climate system in response to sea level rise and orbital forcing.

DOI

https://doi.org/10.31223/X52W4H

Subjects

Biogeochemistry, Climate, Earth Sciences, Geology, Physical Sciences and Mathematics, Planetary Hydrology

Keywords

hydrogen isotopes, Indo-Pacific Warm Pool, Glacial-Interglacial, Paleotemperature, Sundaland

Dates

Published: 2021-10-27 14:20

License

CC BY Attribution 4.0 International

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