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Publication Date
31 January 2018

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

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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.
“Lagrangian Timescales Of Southern Ocean Upwelling In A Hierarchy Of Model Resolutions”. 2018. Geophysical Research Letters 48: 891-898. doi:10.1002/2017gl076045.
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