Seasonal Meandering of the Polar Front Upstream of the Kerguelen Plateau

Etienne Pauthenet (1) , Fabien Roquet (1, 2) , Gurvan Madec (3) , Christophe Guinet (4) , Mark A. Hindell (5, 6) , Clive R. Mcmahon (5, 7, 8) , Robert G. Harcourt (8) , David Nerini (9)

1 MISU - Department of Meteorology [Stockholm]
2 Department of Marine Sciences [Gothenburg]
3 NEMO R&D - Nucleus for European Modeling of the Ocean
4 CEBC - Centre d'Études Biologiques de Chizé - UMR 7372
5 IMAS - Institute for Marine and Antarctic Studies [Hobart]
6 ACE-CRC - Antarctic Climate and Ecosystems Cooperative Research Centre
7 USIMS - University of Sydney Institute of Marine Science
8 Dept of Biological Sciences [Australia]
9 MIO - Institut méditerranéen d'océanologie

The location of the Antarctic Polar Front (PF) is mapped in the Southern Indian Ocean by decomposing the shape of temperature and salinity profiles into vertical modes using a functional Principal Component Analysis. We define the PF as the northernmost minimum of temperature at the subsurface andrepresent it as a linear combination of the first three modes. This method is applied on an ocean reanalysis data set and on in situ observations, revealing a seasonal variability of the PF latitudinal position that is most pronounced between the Conrad Rise and the Kerguelen Plateau. This shift coincides with variations in the transport across the Northern Kerguelen Plateau. We suggest that seasonal changes of the upper stratification may drive the observed variability of the PF, with potentially large implications for thepathways and residence time of water masses over the plateau and the phytoplankton bloom extending southeast of the Kerguelen Islands.

Domaines: Sciences de l'environnement

Etienne Pauthenet, Fabien Roquet, Gurvan Madec, Christophe Guinet, Mark A. Hindell, et al.. Seasonal Meandering of the Polar Front Upstream of the Kerguelen Plateau. Geophysical Research Letters, 2018, 45 (18), pp.9774-9781. ⟨10.1029/2018GL079614⟩. ⟨hal-02024254⟩