Modelling of the end of last Ice Age in transient framework with a coupled climate model ...

The last deglaciation was characterized by a sequence of abrupt climate events thought to be linked to rapid changes in Atlantic meridional overturning circulation (AMOC). The sequence includes a weakening of the AMOC after the Last Glacial Maximum (LGM) during Heinrich Stadial 1 (HS1), which ends w...

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Bibliographic Details
Main Author: Sun, Yuchen
Format: Thesis
Language:English
Published: Universität Bremen 2022
Subjects:
Termination 1
Heinrich Stadials HS
Bølling/Allerød interstadial
Abrupt climate change
AMOC
self-oscillation
530
Ice Sheet
NADW
North Atlantic Deep Water
North Atlantic
Online Access:https://dx.doi.org/10.26092/elib/2101
https://media.suub.uni-bremen.de/handle/elib/6762
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Summary:The last deglaciation was characterized by a sequence of abrupt climate events thought to be linked to rapid changes in Atlantic meridional overturning circulation (AMOC). The sequence includes a weakening of the AMOC after the Last Glacial Maximum (LGM) during Heinrich Stadial 1 (HS1), which ends with an abrupt AMOC recovery giving rise to Bølling/Allerød (B/A) warming. This transition occurs under a background with persistent deglacial meltwater fluxes (MWF) that are deemed to play a negative role in North Atlantic Deep Water (NADW) formation. Using a fully coupled Earth system model COSMOS with a range of deglacial boundary conditions and reconstructed deglacial meltwater fluxes, we show that deglacial CO2 rise and ice sheet decline modulate the sensitivity of the AMOC to these fluxes. While declining ice sheets increase the sensitivity, increasing atmospheric CO2 levels tend to counteract this effect. These effects, therefore, might account for the occurrence of abrupt AMOC increase in the presence of ...

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