FN Archimer Export Format
PT J
TI Controls on Dense Shelf Water formation in four East Antarctic polynyas
BT 
AF Portela, Esther
   Rintoul, Stephen R.
   Herraiz‐Borreguero, Laura
   Roquet, Fabien
   Bestley, Sophie
   van Wijk, Esmee
   Tamura, Takeshi
   McMahon, Clive R.
   Guinet, Christophe
   Harcourt, Robert
   Hindell, Mark A.
AS 1:1,2;2:3,4,5;3:3,5;4:6;5:1,4;6:3,4;7:7,8;8:1,9;9:10;10:11;11:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;11:;
C1 Institute for Marine and Antarctic Studies University of Tasmania Hobart7001 ,Australia
   Univ. Brest Laboratoire d’Océanographie Physique et Spatiale CNRS IRD Ifremer Plouzané ,France
   Commonwealth Scientific and Industrial Research Organization (CSIRO) Oceans and Atmosphere Hobart7001, Australia
   Australian Antarctic Program Partnership Institute for Marine and Antarctic Studies University of Tasmania Hobart7001, Australia
   Centre for Southern Hemisphere Oceans Research Centre (CSHOR) Hobart7001, Australia
   Department of Marine Sciences University of Gothenburg Gothenburg40530, Sweden
   National Institute of Polar Research Tachikawa190‐8518, Japan
   Graduate University for Advanced Studies (SOKENDAI) Tachikawa190‐8518 ,Japan
   Integrated Marine Observing System Animal Tagging sub‐Facility Sydney Institute of Marine Science Mosman2088 ,Australia
   Centre d’Etudes Biologiques de Chizé CNRS 79360 Villiers en Bois France Villiers en Bois, France
   School of Natural Sciences Macquarie University Sydney2109 , Australia
C2 UNIV TASMANIA, AUSTRALIA
   UBO, FRANCE
   CSIRO, AUSTRALIA
   UNIV TASMANIA, AUSTRALIA
   CSHOR, AUSTRALIA
   UNIV GOTHENBURG, SWEDEN
   NATL INST POLAR RES, JAPAN
   SOKENDAI, JAPAN
   SYDNEY INST MARINE SCI, AUSTRALIA
   CNRS, FRANCE
   UNIV SYDNEY, AUSTRALIA
UM LOPS
IN WOS Cotutelle UMR
   copubli-france
   copubli-europe
   copubli-int-hors-europe
IF 3.6
TC 5
UR https://archimer.ifremer.fr/doc/00806/91750/97714.pdf
   https://archimer.ifremer.fr/doc/00806/91750/97715.pdf
LA English
DT Article
DE ;Dense Shelf Water formation;East Antarctic polynyas;sea-ice formation;water masses
AB Coastal polynyas are key formation regions for Dense Shelf Water (DSW) that ultimately contributes to the ventilation of the ocean abyss. However, not all polynyas form DSW. We examine how the physiographic setting, water-mass distribution and transformation, water column stratification, and sea-ice production regulate DSW formation in four East Antarctic coastal polynyas. We use a salt budget to estimate the relative contribution of sea-ice production and lateral advection to the monthly change in salinity in each polynya. DSW forms in Mackenzie polynya due to a combination of physical features (shallow water depth and a broad continental shelf) and high sea-ice production. Sea-ice formation begins early (March) in Mackenzie polynya, counteracting fresh advection and establishing a salty mixed layer in autumn that preconditions the water column for deep convection in winter. Sea-ice production is moderate in the other three polynyas, but saline DSW is not formed (a fresh variety is formed in the Barrier polynya). In the Shackleton polynya, brine rejection during winter is insufficient to overcome the very fresh autumn mixed layer. In Vincennes Bay, a strong inflow of modified Circumpolar Deep Water stratifies the water column, hindering deep convection and DSW formation. Our study highlights that DSW formation in a given polynya depends on a complex combination of factors, some of which may be strongly altered under a changing climate, with potentially important consequences for the ventilation of the deep ocean, the global meridional overturning circulation, and the transport of ocean heat to Antarctic ice shelves. Key Points We determined the physical factors enhancing (or hindering) DSW formation in four East Antarctic polynyas during a well sampled year Relatively high salinity in early winter and high sea-ice formation favor Dense Shelf Water formation in Mackenzie Polynya The properties and volume of DSW formed in a coastal polynya depend on its preconditioning as well as on sea-ice formation Plain Language Summary Coastal polynyas are regions of open water surrounded by sea ice. As sea ice forms, it is pushed offshore by strong winds blowing from the Antarctic continent, keeping the polynya ice-free. Salt is released into the water below as sea ice forms, increasing the salinity and density of the water column. In some polynyas, this water is dense enough to sink from the continental shelf to supply a network of bottom ocean currents that influences global climate. In other polynyas, the water in winter never gets dense enough to reach the ocean abyss. Using data collected by instrumented elephant seals, we investigated the main factors controlling dense water formation in four East Antarctic polynyas. We found that dense water production is related to the strength of sea-ice formation, as expected, but also depends on the salinity at the start of winter. The geographical and physical characteristics of the polynyas and regional circulation also modulate the final water density. Our findings provide insight into how dense water formation in East Antarctic polynyas might respond to future changes in climate and thereby influence the transport of ocean heat to the Antarctic continent and the melt of ice shelves. 
PY 2022
PD DEC
SO Journal Of Geophysical Research-oceans
SN 2169-9275
PU American Geophysical Union (AGU)
VL 127
IS 12
UT 000928053100005
DI 10.1029/2022JC018804
ID 91750
ER

EF