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

TitleLagrangian Timescales of Southern Ocean Upwelling in a Hierarchy of Model Resolutions
Publication TypeJournal Article
Year of Publication2018
AuthorsDrake, Henri F., Morrison Adele K., Griffies Stephen M., Sarmiento Jorge L., Weijer Wilbert, and Gray Alison R.
JournalGeophysical Research Letters
Volume9292510011333451038442838325-32656842764647448421214040
Date Published01/2018
Abstract / 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.

URLhttp://doi.wiley.com/10.1002/2017GL076045
DOI10.1002/2017GL076045
Journal: Geophysical Research Letters
Year of Publication: 2018
Volume: 9292510011333451038442838325-32656842764647448421214040
Date Published: 01/2018

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.

DOI: 10.1002/2017GL076045
Citation:
Drake, HF, AK Morrison, SM Griffies, JL Sarmiento, W Weijer, and AR Gray.  2018.  "Lagrangian Timescales of Southern Ocean Upwelling in a Hierarchy of Model Resolutions."  Geophysical Research Letters 9292510011333451038442838325-32656842764647448421214040.  https://doi.org/10.1002/2017GL076045.