Impacts of volcanic eruptions on the Tropical Atlantic and South America hydroclimate during the last millennium

Abstract

The associated PhD project focuses on the impact of great volcanic eruptions on the dominant mechanisms of seasonal-to-interdecadal variability of the Atlantic Subtropical Cells (STC), its connection with the leading modes of Atlantic Tropical sea surface temperature (SST) variability and, therefore, how the South American hydroclimate responds to these processes. The Last Millennium (LM) is a period frequently used to understand the effects of volcanism on the climate system, given the similarity of the background conditions of the climate with today, but without the anthropogenic forcing. The pre-industrial millennium is marked by great and frequent volcanic activity that affects the climate in several ways, with internal feedbacks that may amplify the resultants. The direct effect of volcanism is the reduction of incoming short wave, that results in net cooling of the surface. However, its climatic effects are not limited to direct changes; it can also trigger dynamical alterations in the surface-subsurface ocean circulation (i.e. Atlantic STCs), which may introduce slower recovery of the climate system from the volcanic perturbation. In this context, this proposal aims to understand how eruptions from the LM modulate the dynamics that controls the Atlantic STC and its relationship with the South America hydroclimate. It is proposed to develop this project at the Laboratory of Oceanography and Climate: Experiments and Numerical Approaches, Pierre-Simon Laplace Institute (LOCEAN-IPSL) at Sorbonne University under the supervision of Dr. Myriam Khodri, who is involved with the LM 6th Coupled Model Intercomparision Project (CMIP6) runs and has large knowledge in changes in theclimate associated to volcanic events. (AU)