Imperial College London
Alternate

ProfessorRalfToumi

Faculty of Natural Sciences, The Grantham Institute for Climate Change

Co-Director, Grantham Institute - Climate Change&Environment
 
 
 
//

Contact

 

+44 (0)20 7594 7668r.toumi Website CV

 
 
//

Location

 

713Huxley BuildingSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Trivedi:2016:10.1007/s10236-016-1010-7,
author = {Trivedi, A and Toumi, R},
doi = {10.1007/s10236-016-1010-7},
journal = {Ocean Dynamics},
pages = {1--21},
title = {Mechanisms of bottom boundary fluxes in a numerical model of the Shetland shelf},
url = {http://dx.doi.org/10.1007/s10236-016-1010-7},
volume = {67},
year = {2016}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Across-slope bottom boundary layer (BBL) fluxes on the shelf-edge connectthis region to deeper waters. Two proposed ways in which across-slope BBLfluxes can occur, in regions that have a slope current aligned to the bathymetry, are:the frictional veering of bottom currents termed the ‘Ekman drain’; and through localwind-forced downwelling (wind-driven surface Ekman flow with an associated bottomflow). We investigate the variability, magnitude and spatial scale of BBL fluxeson the Shetland shelf, which has a prominent slope current, using a high-resolution(∼ 2 km) configuration of the MITgcm model. Fluxes are analysed in the BBL atthe shelf break near the 200 m isobath and are found to have a seasonal variabilitywith high/low volume transport in winter/summer respectively. By using a multivariateregression approach, we find that the locally wind-driven Ekman transport playsno explicit role in explaining daily bottom fluxes. We can better explain the variabilityof the across-slope BBL flux as a linear function of the speed and across-slopecomponent of the interior flow, corresponding to an Ekman plus mean-flow flux. Weestimate that the mean-flow is a greater contributor than the Ekman flux to the BBLflux. The spatial heterogeneity of the BBL fluxes can be attributed to the mean-flow,which has a much shorter decorrelation length compared to the Ekman flux. We concludethat both the speed and direction of the interior current determines the dailyBBL flux. The wind does not explicitly contribute through local downwelling, butmay influence the interior current and therefore implicitly the BBL fluxes on longertimescales.
AU  - Trivedi,A
AU  - Toumi,R
DO  - 10.1007/s10236-016-1010-7
EP  - 21
PY  - 2016///
SN  - 1616-7341
SP  - 1
TI  - Mechanisms of bottom boundary fluxes in a numerical model of the Shetland shelf
T2  - Ocean Dynamics
UR  - http://dx.doi.org/10.1007/s10236-016-1010-7
UR  - http://hdl.handle.net/10044/1/41784
VL  - 67
ER  -
Download