Day 4

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Paper title Meltwater lenses in the Chukchi and the Beaufort Seas during summer 2019 : from in-situ to synoptic view.
Authors
  1. Alexandre Supply University of Brest, LOPS Laboratory, IUEM, UBO–CNRS–IRD–Ifremer, Plouzané, France Speaker
  2. Jacqueline Boutin CNRS/LOCEAN
  3. Nicolas Kolodziejczyk University of Brest, LOPS Laboratory, IUEM, UBO–CNRS–IRD–Ifremer
  4. Gilles Reverdin CNRS/LOCEAN
  5. Camille Lique University of Brest, LOPS Laboratory, IUEM, UBO–CNRS–IRD–Ifremer
  6. Jean Luc Vergely Jean-Luc Vergely ACRI-ST
  7. Xavier Perrot LMD / IPSL, CNRS, ENS, PSL
Form of presentation Poster
Topics
  • A8. Ocean
    • A8.07 Oceanographic Change of the Arctic Ocean From Space
Abstract text Understanding surface processes during sea ice melt season in the Arctic Ocean is crucial in the context of ongoing Arctic change. The Chukchi and the Beaufort Seas are the Arctic regions where salty and warm Pacific Water (PW) flows in from the Bering Strait and interacts with sea ice, contributing to its melt during summer. For the first time, thanks to in-situ measurements from two saildrones deployed in summer 2019, and SMOS (Soil Moisture and Ocean Salinity) and SMAP (Soil Moisture Active Passive) satellite Sea Surface Salinity (SSS), we observe large low SSS anomalies induced by sea ice melt, referred as meltwater lenses (MWL).

The largest MWL observed by the saildrones during this period covers a large part of the Chukchi shelf. It is associated with a SSS anomaly reaching 5pss, and persists for a long time (up to one month). In this MWL, the low SSS pattern influences the air-sea momentum transfer in the upper ocean, resulting in a reduced shear of currents between 10 and 20 meters depth.

L-Band radiometric SSS allows an identification of the different water masses found in the region during summer 2019 and their evolution as the sea ice edge retreats over the Chukchi and the Beaufort Seas. Two MWL detected in these two regions exhibit different mechanism of formation: in the Beaufort Sea, the MWL tends to follow the sea ice edge as it retreats meridionally whilst in the Chukchi Sea, a large persisting MWL generated by the advection of a thin sea ice filament is observed.

Taking advantage of the demonstrated ability of SSS satellite observations to monitor MWL and the 12 years-long SMOS time series, we further examine the interannual variability of SSS during sea ice retreat over the Chukchi and Beaufort Seas for the last 12 years.