FN Archimer Export Format
PT J
TI Seasonal transformation and spatial variability of water masses within MacKenzie polynya, Prydz Bay
BT 
AF Portela, Esther
   Rintoul, Stephen R.
   Bestley, Sophie
   Herraiz‐Borreguero, Laura
   Wijk, Esmee
   McMahon, Clive R.
   Roquet, Fabien
   Hindell, Mark
AS 1:1,2;2:3,4,5;3:1,4;4:3,5;5:3,4;6:1,6;7:7;8:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;
C1 Institute for Marine and Antarctic Studies University of Tasmania , Hobart 7001, Australia
   Univ. Brest, Laboratoire d’Océanographie Physique et Spatiale CNRS IRD Ifremer Plouzané,France
   CSIRO Oceans and Atmosphere ,Hobart 7001, Australia
   Australian Antarctic Program Partnership Institute for Marine and Antarctic Studies, University of Tasmania , Hobart 7001 ,Australia
   Centre for Southern Hemisphere research (CSHOR) ,Australia
   Integrated Marine Observing System Animal Tagging sub‐Facility Sydney Institute of Marine Science Mosman 2088 , Australia
   Department of Marine Sciences, University of Gothenburg Gothenburg , 40 530 ,Sweden
C2 UNIV TASMANIA, AUSTRALIA
   UBO, FRANCE
   CSIRO OCEANS AND ATMOSPHERE, AUSTRALIA
   UNIV TASMANIA, AUSTRALIA
   CSHOR, AUSTRALIA
   IMOS, AUSTRALIA
   UNIV GOTHENBURG, SWEDEN
UM LOPS
IN WOS Cotutelle UMR
   copubli-europe
   copubli-int-hors-europe
IF 3.938
TC 5
UR https://archimer.ifremer.fr/doc/00739/85134/90102.pdf
   https://archimer.ifremer.fr/doc/00739/85134/90103.pdf
LA English
DT Article
DE ;Antarctic polynyas;dense shelf water;water masses
AB We provide a detailed description of the spatial distribution, seasonality and transformation of the main water masses within MacKenzie Polynya (MP) in Prydz Bay, East Antarctica, using data from instrumented southern elephant seals. Dense Shelf Water (DSW) formation in MP shows large spatial variability that is related to the (i) local bathymetry, (ii) water column preconditioning from the presence/absence of different water masses, and (iii) proximity to the Amery Ice Shelf meltwater outflow. MP exhibits sustained sea ice production and brine rejection (thus, salinity increase) from April to October. However, new DSW is only formed from June onward, when the mixed layer deepens and convection is strong enough to break the stratification set by Antarctic Surface Water above and Ice Shelf Water below. We found no evidence of DSW export from MP to Darnley polynya, as previously suggested. Rather, our observations suggest some DSW formed in Darnley Polynya may drain towards the western Prydz Bay. Then, DSW is exported offshore from Prydz Bay through the Prydz Channel. The interplay between sea ice formation, meltwater input, and sea floor topography is likely to explain why some coastal polynyas form more DSW than others, as well as the temporal variability in DSW formation within a particular polynya. Plain Language Summary Coastal polynyas are regions of open water surrounded by sea ice. They form when strong winds from the Antarctic continent push newly-formed sea ice away from the coast, as rapidly as it forms. Polynyas are therefore important sea ice factories. When sea ice forms, salt is released into the water below, increasing its salinity and density. The densest water in the World Ocean can be traced back to a few coastal polynyas along the Antarctic continent. This dense water formed in polynyas supplies the deep limb of a network of ocean currents that influences climate on global scales. Despite their importance, coastal polynyas remain poorly understood as they are difficult to reach and observe. Using data collected by instrumented elephant seals, we investigated seasonal changes in the MacKenzie Polynya in Prydz Bay, East Antarctica. Our study shows that dense water production is regulated by a complex interplay between three factors: strength of sea ice formation, the input of meltwater from ice shelves, and steering of the flow by sea floor topography. These new observations collected by seals contribute to a better understanding of dense water formation and the vulnerability of the global overturning circulation to future change. 
PY 2021
PD DEC
SO Journal Of Geophysical Research-oceans
SN 2169-9275
PU American Geophysical Union (AGU)
VL 126
IS 12
UT 000735870300045
DI 10.1029/2021JC017748
ID 85134
ER

EF