Glacial ice and atmospheric forcing on the Mertz Glacier Polynya over the past 250 years

Philippine Campagne (1, 2, 3) , Xavier Crosta (1) , Marie-Noëlle Houssais (4) , Didier Swingedouw (5) , Sabine Schmidt (1) , Antoine Martin (4) , E. Devred (2) , S. Capo (1) , V. Marieu (1) , Guillaume Massé (2, 6) , Ivia Closset (6)

1 EPOC - Environnements et Paléoenvironnements OCéaniques
2 Takuvik Joint International Laboratory ULAVAL-CNRS
3 LOCEAN - Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques
4 VOG - Variabilité de l'Océan et de la Glace de mer
5 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
6 BTP - Biogéochimie-Traceurs-Paléoclimat

The Mertz Glacier Polynya off George V Land, East Antarctica, is a source of Adélie Land Bottom Water, which contributes up to B25% of the Antarctic Bottom Water. This major polynya is closely linked to the presence of the Mertz Glacier Tongue that traps pack ice upstream. In 2010, the Mertz Glacier calved a massive iceberg, deeply impacting local sea ice conditions and dense shelf water formation. Here we provide the first detailed 250-year long reconstruction of local sea ice and bottom water conditions. Spectral analysis of the data sets reveals large and abrupt changes in sea surface and bottom water conditions with a B70-year cyclicity, associated with the Mertz Glacier Tongue calving and regrowth dynamics. Geological data and atmospheric reanalysis, however, suggest that sea ice conditions in the polynya were also very sensitive to changes in surface winds in relation to the recent intensification of the Southern Annular Mode.

Domaines: Océan, Atmosphère; Océanographie; Climatologie

Philippine Campagne, Xavier Crosta, Marie-Noëlle Houssais, Didier Swingedouw, Sabine Schmidt, et al.. Glacial ice and atmospheric forcing on the Mertz Glacier Polynya over the past 250 years. Nature Communications, 2015, 6, pp.6642. ⟨10.1038/ncomms7642⟩. ⟨hal-02105559⟩