Lagrangian Timescales of Southern Ocean Upwelling in a Hierarchy of Model Resolutions

In this paper we study upwelling pathways and timescales of Circumpolar Deep Water (CDW) in a hierarchy of models using a Lagrangian particle tracking method. Lagrangian timescales of CDW upwelling decrease from 87 years to 31 years to 17 years as the ocean resolution is refined from 1° to 0.25° to...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Drake, Henri F., Morrison, Adele, Griffies, S. M., Sarmiento, Jorge L., Weijer, Wilbert, Gray, Alison R.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Geophysical Union
Subjects:
meridional overturning circulation
Southern Ocean
Circumpolar Deep Water
upwelling
eddy parameterization
ocean modeling
Online Access:http://hdl.handle.net/1885/241039
https://doi.org/10.1002/2017GL076045
https://openresearch-repository.anu.edu.au/bitstream/1885/241039/3/2017GL076045.pdf.jpg
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Summary:In this paper we study upwelling pathways and timescales of Circumpolar Deep Water (CDW) in a hierarchy of models using a Lagrangian particle tracking method. Lagrangian timescales of CDW upwelling decrease from 87 years to 31 years to 17 years as the ocean resolution is refined from 1° to 0.25° to 0.1°. We attribute some of the differences in timescale to the strength of the eddy fields, as demonstrated by temporally degrading high‐resolution model velocity fields. Consistent with the timescale dependence, we find that an average Lagrangian particle completes 3.2 circumpolar loops in the 1° model in comparison to 0.9 loops in the 0.1° model. These differences suggest that advective timescales and thus interbasin merging of upwelling CDW may be overestimated by coarse‐resolution models, potentially affecting the skill of centennial scale climate change projections. H. F. D. was fully supported by and all other authors (except S. M. G.) were partially supported by Department of Energy’s RGCM program through grant DE-SC0012457. J. L. S. and A. R. G. were partially supported by Southern Ocean Carbon and Climate Observation and Modeling through grant PLR-1425989. A. R. G. was supported by the Climate and Global Change Postdoctoral Fellowship from the National Oceanic and Atmospheric Administration. A. K. M. was supported by the Australian Research Council DECRA Fellowship DE170100184.

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