In:
Ocean Science, Copernicus GmbH, Vol. 19, No. 4 ( 2023-08-04), p. 1183-1201
Abstract:
Abstract. We investigated the connectivity properties of an
idealized western boundary current system separating two ocean gyres, where
the flow is characterized by a well-defined mean circulation as well as
energetic fine-scale features (i.e., mesoscale and submesoscale currents).
We used a time-evolving 3D flow field from a high-resolution (HR-3D) ocean
model of this system. In order to evaluate the role of the fine scales in
connectivity estimates, we computed Lagrangian trajectories in three
different ways: using the HR-3D flow, using the same flow but filtered on a
coarse-resolution grid (CR-3D), and using the surface layer flow only
(HR-SL). We examined connectivity between the two gyres along the western
boundary current and across it by using and comparing different metrics, such
as minimum and averaged values of transit time between 16 key sites, arrival
depths, and probability density functions of transit times. We find that
when the fine-scale flow is resolved, the numerical particles connect pairs
of sites faster (between 100 to 300 d) than when it is absent. This
is particularly true for sites that are along and near the jets separating
the two gyres. Moreover, the connectivity is facilitated when 3D instead of
surface currents are resolved. Finally, our results emphasize that ocean
connectivity is 3D and not 2D and that assessing connectivity properties
using climatologies or low-resolution velocity fields yields strongly biased
estimates.
Type of Medium:
Online Resource
ISSN:
1812-0792
DOI:
10.5194/os-19-1183-2023
DOI:
10.5194/os-19-1183-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2183769-7
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