Multi-annual variability of a new proxy-constrained modeled AMOC from 1450–1780 CE
Year: 2023
Type: preprint
Abstract: . The ongoing discussion about the Atlantic Meridional Overturning Circulation (AMOC) slowdown over the 21st century requires an understanding of preindustrial AMOC variability. Here, we present a new AMOC reconstruction during the Little Ice Age from 1450–1780 CE, generated with a novel nudging technique. The technique uses a 10-member ensemble of ocean-model simulations nudged to proxy-reconstructed sea surface temperature. The new reconstruction improves existing knowledge of the AMOC variability and underlying processes, showing that the AMOC weak phases under stable atmospheric CO2 conditions are mainly driven by a 4-to-7-year lagged effect of surface heat flux associated with the North Atlantic Oscillation (NAO). However, the strong phases are a response to instantaneous surface wind stress. Analyses of our AMOC reconstruction reaffirm previous findings about the mechanisms of AMOC variability and its link to the NAO. In addition, we show that processes leading to the phases of weak and strong AMOC are non-symmetric. Overall, the nudging technique enables us to better constrain past AMOC variability.
DOI: 10.5194/cp-2023-67
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
Funder: H2020 European Research Council
OpenAlex ID: W4386835596