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{Haigh:2020:10.1016/j.dsr.2020.103264,
author = {Haigh, M and Sun, L and Shevchenko, I and Berloff, P},
doi = {10.1016/j.dsr.2020.103264},
journal = {Deep Sea Research Part I: Oceanographic Research Papers},
pages = {1--8},
title = {Tracer-based estimates of eddy-induced diffusivities},
url = {http://dx.doi.org/10.1016/j.dsr.2020.103264},
volume = {160},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - This study provides estimates of the mean eddy-induced diffusivities of passive tracers in a three-layer, double-gyre quasigeostrophic (QG) simulation. A key aspect of this study is the use of a spatial filter to separate the flow and tracer fields into small-scale and large-scale components, and we compare results with those obtained using Reynolds temporal averaging. The eddy tracer flux is related to a rank-2 diffusivity tensor via the flux-gradient relation, which is solved for a pair of tracers with misaligned large-scale gradients. We concentrate on the symmetric part of the resulting diffusivity tensor which represents irreversible mixing processes. The eigenvalues of the symmetric tensor exhibit complicated behaviour, but a particularly dominant and robust feature is the positive/negative eigenvalue pairs, which physically represent filamentation of the tracer concentration. The large off-diagonal diffusivity tensor component is the primary contributor to the eigenvalue polarity, and since this is such a prevalent feature we argue that the (horizontal) eddy-induced diffusivity should always be treated as a full  tensor. Diffusivity magnitudes are largest in the upper layer and in the eastward jet region, where the eddying flow is strongest. After removing the rotational part of the eddy tracer flux, typical mean diffusivities (eigenvalues) in the upper-layer are on the order of  m2 s−1 in the jet region and  m2 s−1 elsewhere. We also confirm that the time-mean of the diffusivity calculated from instantaneous fluxes is not the same as the diffusivity associated with the time-mean fluxes.
AU  - Haigh,M
AU  - Sun,L
AU  - Shevchenko,I
AU  - Berloff,P
DO  - 10.1016/j.dsr.2020.103264
EP  - 8
PY  - 2020///
SN  - 0967-0637
SP  - 1
TI  - Tracer-based estimates of eddy-induced diffusivities
T2  - Deep Sea Research Part I: Oceanographic Research Papers
UR  - http://dx.doi.org/10.1016/j.dsr.2020.103264
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000535357000011&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://www.sciencedirect.com/science/article/pii/S0967063720300522?via%3Dihub
UR  - http://hdl.handle.net/10044/1/80096
VL  - 160
ER  -
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