Freshwater fluxes in the Weddell Gyre: Results from δ^18O

doi: 10.1098/rsta.2013.0298

abstract: Full-depth measurements of δ^18O from 2008 to 2010 enclosing the Weddell Gyre in the Southern Ocean are used to investigate the regional freshwater budget. Using complementary salinity, nutrients and oxygen data, a four-component mass balance was applied to quantify the relative contributions of meteoric water (precipitation/glacial input), sea-ice melt and saline (oceanic) sources. Combination of freshwater fractions with velocity fields derived from a box inverse analysis enabled the estimation of gyre-scale budgets of both freshwater types, with deep water exports found to dominate the budget. Surface net sea-ice melt and meteoric contributions reach 1.8% and 3.2%, respectively, influenced by the summer sampling period, and -1.7% and +1.7% at depth, indicative of a dominance of sea-ice production over melt and a sizable contribution of shelf waters to deep water mass formation. A net meteoric water export of approximately 37 mSv is determined, commensurate with local estimates of ice sheet outflow and precipitation, and the Weddell Gyre is estimated to be a region of net sea-ice production. These results constitute the first synoptic benchmarking of sea-ice and meteoric exports from the Weddell Gyre, against which future change associated with an accelerating hydrological cycle, ocean climate change and evolving Antarctic glacial mass balance can be determined.

@article{Brown-etal-2014,
author = {Brown, P. J. and Meredith, M. P. and Jullion, L. and Naveira~Garabato, A. C. and Torres-Vald\?{e}s, S. and Holland, P. R. and Leng, M. J. and Venables, H. J.},
title = {Freshwater fluxes in the Weddell Gyre: Results from $\delta^{18}$O},
journal = {Phil. Trans. Royal Soc.},
year = {2014},
pages = {20130298},
volume = {372},
issue = {2019},
doi = {10.1098/rsta.2013.0298},
url = {https://eprints.soton.ac.uk/356911/}
}