Atmospheric mercury cycling in remote areas of the Southern Hemisphere : focus on the subantarctic marine boundary layer and on the Antarctic continent

• Main Author: Angot, Hélène
• Other Authors: Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Université Grenoble Alpes, Aurélien Dommergue
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2016
• Subjects: Mercury; Atmospheric cycling; Southern Hemisphere; Antarctica; Subantarctic marine boundary layer; Mercure; Cycle atmosphérique; Hémisphère Sud; Antarctique; Couche limite marine subantarctique; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarctic; Dumont d’Urville; East Antarctic Ice Sheet; Indian; The Antarctic; Amsterdam Island; Antarc*; Antarctique*; Ice Sheet
• Online Access: https://tel.archives-ouvertes.fr/tel-01536102; https://tel.archives-ouvertes.fr/tel-01536102/document; https://tel.archives-ouvertes.fr/tel-01536102/file/ANGOT_2016_archivage.pdf

Mercury (Hg) is a metal emitted by both natural and anthropogenic sources. It is of global concern owing to its long-range atmospheric transport, its persistence in the environment, its ability to bioaccumulate in ecosystems, and its negative effects on human health. Large uncertainties associated with atmospheric models – that trace the link from emissions to deposition of Hg onto environmental surfaces – arise as a result of our incomplete understanding of atmospheric processes (oxidation pathways, deposition, and re-emission) and of the scarcity of monitoring data at a global scale. The aim of this PhD work is to improve our understanding of the atmospheric Hg cycling at three remote sites of the Southern Hemisphere: Amsterdam Island (AMS) in the Indian Ocean, Concordia (DC) on the East Antarctic ice sheet, and Dumont d’Urville (DDU) on the East Antarctic coast. Data acquired at AMS suggest a limited atmospheric reactivity of Hg in this part of the globe. The advection of polluted continental air masses being scarce, AMS is a key site for the long-term monitoring of the atmospheric background in the Southern Hemisphere mid-latitudes. Data acquired in Antarctica highlight the occurrence of unprecedented processes in the atmosphere and at the air-snow interface. Due to katabatic winds flowing out from the East Antarctic ice sheet down the steep vertical drops along the coast, processes observed at DC influence the cycle of atmospheric Hg on a continental scale. These scientific breakthroughs will ultimately lead to improved global transport and deposition models. Le mercure (Hg) est un métal émis dans l’atmosphère par des sources naturelles et anthropiques. Il est préoccupant à l’échelle mondiale de par sa propagation atmosphérique sur de longues distances, loin des sources d’émissions, sa persistance dans l’environnement, son potentiel de bioaccumulation dans les chaînes alimentaires aquatiques et ses effets néfastes sur la santé humaine. Les modèles atmosphériques, utilisés pour retracer son cheminement ...