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Communication Dans Un Congrès Année : 2023

Caracterización topológica de la Circulación de retorno meridional del Atlántico

Résumé

An important feature of the paleoclimatic record of the last glacial interval in the North Atlantic is the pronounced millennial variability, commonly referred to as the Dansgaard-Oeschger (D-O) events. These consist of an abrupt warming of a couple of decades of Greenland ice cores and North Atlantic temperature and slow cooling over several centuries, with a periodicity of about 1400 years. The potential bistability of the Atlantic Meridional Overturning Circulation (known as AMOC) immediately points to the possibility that cold and warm climate states are related to its reorganization. Starting from an idealized deterministic 3-degree-of-freedom model of the AMOC, the southernmost extent of sea ice cover is added as a key variable in time (Sevellec and Fedorov, 2015). This time dependence was specially chosen to mimic a glacial-interglacial cycle (AMOC on and off) typical of the late Pleistocene. To study the dynamical properties of the model, we will approach the problem with a topological method. The description provides information on the invariant mechanisms that act to shape a flow in state space and is performed by constructing a templex. A templex (Charó et al., 2022) is a dual mathematical object composed of a cell complex and a directed graph that simultaneously describe the topological structure of the attractor and the action of the flow on that structure. The cell complex approximates the underlying manifold as a layered group of cells glued together by their edges, and the directed graph encodes how the cells are interconnected by the flow. The algebraic analysis of a templex provides the non-equivalent paths of cells on which the complex used to approximate the topological structure of the attractor can be visited. The cell complex and directed graph can be computed from numerical solutions of the model equations, but can also be reconstructed from time series, using embeddings.
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hal-04274457 , version 1 (08-11-2023)

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  • HAL Id : hal-04274457 , version 1

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Caterina Mosto, Gisela Daniela Charó, Pierre Le Bras, Pierre Tandeo, Florian Sévellec, et al.. Caracterización topológica de la Circulación de retorno meridional del Atlántico. 108 Reunión Anual de Física 2023, https://rafa2023.fisica.org.ar/comite-organizador, Sep 2023, Bahía Blanca, Argentina. ⟨hal-04274457⟩

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