Imperial College London
Alternate

ProfessorPavelBerloff

Faculty of Natural Sciences, Department of Mathematics

Professor in Applied Mathematics
 
 
 
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Contact

 

+44 (0)20 7594 9662p.berloff Website

 
 
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Location

 

745Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Sun:2021:10.1017/jfm.2021.472,
author = {Sun, L and Haigh, M and Shevchenko, I and Berloff, P and Kamenkovich, I},
doi = {10.1017/jfm.2021.472},
journal = {Journal of Fluid Mechanics},
pages = {1--27},
title = {On non-uniqueness of the mesoscale eddy diffusivity},
url = {http://dx.doi.org/10.1017/jfm.2021.472},
volume = {920},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Oceanic mesoscale currents (‘eddies’) can have significant effects on the distributions of passive tracers. The associated inhomogeneous and anisotropic eddy fluxes are traditionally parametrised using a transport tensor (K-tensor), which contains both diffusive and advective components. In this study, we analyse the eddy transport tensor in a quasigeostrophic double-gyre flow. First, the flow and passive tracer fields are decomposed into large- and small-scale (eddy) components by spatial filtering, and the resulting eddy forcing includes an eddy tracer flux representing advection by eddies and non-advective terms. Second, we use the flux-gradient relation between the eddy fluxes and the large-scale tracer gradient to estimate the associated K-tensors in their entire structural, spatial and temporal complexity, without making any additional assumptions or simplifications. The divergent components of the eddy tracer fluxes are extracted via the Helmholtz decomposition, which yields a divergent tensor. The remaining rotational flux does not affect the tracer evolution, but dominates the total tracer flux, affecting both its magnitude and spatial structure. However, in terms of estimating the eddy forcing, the transport tensor prevails over its divergent counterpart because of the significant numerical errors induced by the Helmholtz decomposition. Our analyses demonstrate that, in general, the K-tensor for the eddy forcing is not unique, that is, it is tracer-dependent. Our study raises serious questions on how to interpret and use various estimates of K-tensors obtained from either observations or eddy-resolving model solutions.
AU  - Sun,L
AU  - Haigh,M
AU  - Shevchenko,I
AU  - Berloff,P
AU  - Kamenkovich,I
DO  - 10.1017/jfm.2021.472
EP  - 27
PY  - 2021///
SN  - 0022-1120
SP  - 1
TI  - On non-uniqueness of the mesoscale eddy diffusivity
T2  - Journal of Fluid Mechanics
UR  - http://dx.doi.org/10.1017/jfm.2021.472
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000687287700001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/on-nonuniqueness-of-the-mesoscale-eddy-diffusivity/25AE9567D5238488CD0E5AF935F634DF
UR  - http://hdl.handle.net/10044/1/91345
VL  - 920
ER  -
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