DANIAU, Anne-Laure; LOUTRE, Marie-France; SWINGEDOUW, Didier; LAEPPLE, Thomas; BASSINOT, Franck; MALAIZE, Bruno; KAGEYAMA, Masa; CHARLIER, Karine; CARFANTAN, Hervé

doi:10.1016/j.quascirev.2023.108128

Environnements et Paléoenvironnements OCéaniques [EPOC]

LOUTRE, Marie-France
Université Catholique de Louvain = Catholic University of Louvain [UCL]
PAGES International Project Office

SWINGEDOUW, Didier

Environnements et Paléoenvironnements OCéaniques [EPOC]

Langue

Article de revue

Ce document a été publié dans

Quaternary Science Reviews. 2023-06, vol. 310, p. 108128

Résumé en anglais

While the influence of precession on monsoon at low latitudes through insolation forcing is well-known, the role of obliquity is still debated since its influence on the distribution of incoming solar radiation is small in these regions. In southern Africa, long marine and terrestrial sedimentary records attest of a precessional influence on the South African monsoon at orbital time scale. The obliquity signal is occasionally observed in the geological records although modeling results suggest an influence of precession and obliquity on summer monsoon. Here, we present a record of microscopic charcoal from core MD96-2098 located off Namibia covering the past 184,000 years. Our record of fire activity reveals cyclic changes at frequencies of 23, 58 and 12 kyr À1 and lacks the obliquity signal at 41 kyr À1. Changes in fire over southern Africa are interpreted as shifts in large and intense fires spreading in open-grassland savanna as a result of orbitally-driven changes in rainfall intensity associated with the South African monsoon. We show that, despite the absence of a 41 kyr obliquity imprint, the presence of 23, 58 and 12 kyr À1 frequencies likely stems from a nonlinear response of fire to precipitation controlled by a combination of precession and obliquity frequencies, supporting the influence of obliquity on the South African monsoon.< Réduire

Mots clés en anglais

Fire Biomass burning Heterodynes Monsoon Linear and non-linear response Marine sediment

Fire

Biomass burning

Heterodynes

Monsoon

Linear andnon-linearresponse

Marine sediment

URI

https://oskar-bordeaux.fr/handle/20.500.12278/187935

DOI

http://dx.doi.org/10.1016/j.quascirev.2023.108128

Project ANR

Reconstruction des surfaces brulées à partir des particules de microcharbon préservées dans le sédiment marin - ANR-19-CE01-0001

Unités de recherche

EPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805

Voir/Ouvrir

Métadonnées

Partager cette publication !

Licence d’utilisation du document

Precession and obliquity forcing of the South African monsoon revealed by sub-tropical fires