ALEK PETTY
  1. Home
  2. Papers
  3. Sea ice and the ocean mixed layer over the Antarctic shelf seas

Sea ice and the ocean mixed layer over the Antarctic shelf seas

by Alek Petty, Paul Holland, Daniel Feltham (2014)

Info

Citation

Petty, A. A., P. R. Holland, and D. L. Feltham (2014), Sea ice and the ocean mixed layer over the Antarctic shelf seas, The Cryosphere, 8(2), 761–783, doi:10.5194/tc-8-761-2014.

Abstract

An ocean mixed-layer model has been incorporated into the Los Alamos sea ice model CICE to investi- gate regional variations in the surface-driven formation of Antarctic shelf waters. This model captures well the expected sea ice thickness distribution, and produces deep (> 500 m) mixed layers in the Weddell and Ross shelf seas each winter. This results in the complete destratification of the water col- umn in deep southern coastal regions leading to high-salinity shelf water (HSSW) formation, and also in some shallower regions (no HSSW formation) of these seas. Shallower mixed layers are produced in the Amundsen and Bellingshausen seas. By deconstructing the surface processes driving the mixed-layer depth evolution, we show that the net salt flux from sea ice growth/melt dominates the evolution of the mixed layer in all regions, with a smaller contribution from the surface heat flux and a negligible input from wind stress. The Weddell and Ross shelf seas receive an annual surplus of mixing energy at the surface; the Amundsen shelf sea en- ergy input in autumn/winter is balanced by energy extraction in spring/summer; and the Bellingshausen shelf sea experiences an annual surface energy deficit, through both a low energy input in autumn/winter and the highest energy loss in spring/summer. An analysis of the sea ice mass balance demonstrates the contrasting mean ice growth, melt and ex- port in each region. The Weddell and Ross shelf seas have the highest annual ice growth, with a large fraction exported northwards each year, whereas the Bellingshausen shelf sea experiences the highest annual ice melt, driven by the advection of ice from the northeast. A linear regression analysis is performed to determine the link between the autumn/winter mixed-layer deepening and several atmospheric variables. The Weddell and Ross shelf seas show stronger spatial corre- lations (temporal mean – intra-regional variability) between the autumn/winter mixed-layer deepening and several atmo- spheric variables compared to the Amundsen and Belling- shausen. In contrast, the Amundsen and Bellingshausen shelf seas show stronger temporal correlations (shelf sea mean – interannual variability) between the autumn/winter mixed layer deepening and several atmospheric variables.

Bibtex

@article{petty2015,
    title = {Sea ice and the ocean mixed layer over the Antarctic shelf seas},
    volume = {8},
    issn = {1994-0424},
    doi = {10.5194/tc-8-761-2014},
    number = {2},
    journal = {The Cryosphere},
    author = {Petty, A. A. and Holland, P. R. and Feltham, D. L.},
    year = {2014},
    pages = {761--783}
}