Understanding Interannual Variations of the Local Rainy Season over the Southwest Indian Ocean

Li, Hanying; Hu, Peng; Zhang, Qiong; Sinha, Ashish; Cheng, Hai

doi:10.1007/s00376-021-1065-3

Cited by 2 publications

(1 citation statement)

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“…Rodrigues Island and northwest Madagascar are likely responding to different climate forcings and/or local effects since they are climatologically distinct. As noted previously, Rodrigues Island lies directly in the easterly trade wind belt, while western Madagascar has a more complex relationship to summer easterlies (Li et al, 2021). Scroxton et al (2017) suggested that northwest Madagascar may respond more to zonal climate variability associated with western Indian Ocean SSTs and the east to west tropical Indian Ocean sea surface temperature gradients than to meridional climate variability.…”

Section: Discussionmentioning

confidence: 84%

A speleothem record of hydroclimate variability in northwestern Madagascar during the mid-late Holocene

Williams,

Burns,

Scroxton

et al. 2024

The Holocene

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We present a continuous high-resolution precisely dated multiproxy record of hydroclimate variability at Anjohibe cave in northwestern Madagascar using speleothem AB13. The record spans from ~4484 y BP to ~2863 y BP. Stalagmite δ18O, δ13C and Sr/Ca ratios show very similar changes in hydroclimate. The mechanism controlling Sr/Ca changes, however, from prior calcite precipitation to degree of dolomite dissolution at about 4 ky BP. Our record is also in good agreement with previously published speleothem records from the same area. This agreement and multiproxy consensus indicate that AB13 provides a robust record of hydroclimate variability, including a continuous record of hydroclimate variability across the 4.2 ka event. This 4.2 ka event in Madagascar is marked by two distinct periods of drying between ~3900 y BP to 4300 y BP. A dry 4.2 ka event at this Southern Hemisphere site helps limit possible mechanisms for the event, indicating that a meridional shift to the south in the ITCZ is not responsible for the 4.2 ka event. In addition, the 4.2 ka event does not stand out as a unique dry period in our record. The longest and driest period of the record lasted ~300 years with peak dryness at ~3000 y BP. Our record differs significantly from a speleothem record from Rodrigues Island, located ~1800 km to the east of our study area in Madagascar suggesting different climatological controls on northwest Madagascar and more oceanic sites to the east.

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Section: Discussionmentioning

confidence: 84%