South American summer monsoon reconstruction over the past millennium from isotopic proxies
Séminaire de Mathias VUILLE, mardi 27 juin à 11h, salle Lliboutry, Bâtiment Glaciologie
Title : South American summer monsoon reconstruction over the past millennium from isotopic proxies
Relatively little is known about the history of the South American Summer Monsoon (SASM) during the past millennium or its sensitivity to changes in external forcing. Yet such information is needed in order to put recent climate anomalies such as the 2005 and 2010 droughts in the Amazon basin in a longer-term perspective and to more accurately project future changes in the monsoon mean state and its extremes (flooding or droughts) due to anthropogenic greenhouse gas forcing. Proxies that incorporate the stable isotopic composition of meteoric waters (speleothems, ice cores, lake sediments, etc.) provide the unique opportunity to assess such changes, as they are affected by changes in the large-scale circulation over the core monsoon region. Hence isotopic proxies offer the potential to establish a multi-proxy network along the entire range of the SASM belt from the Andes in the west to the Atlantic coast in the east. Here we will review some novel aspects of this ongoing effort to reconstruct the SASM history over the past millennium, including a new isotopic forward model for tropical ice cores and model analysis of volcanic forcing impacts on the South American monsoon over the past millennium.
Par Mathias Vuille de l’Université de New York (USA) est en visite à l’IGE pour 1 mois (prof invité OSUG/UGA).
Séminaire animé par Antoine Rabatel (IGE-CYME).