TY - GEN
T1 - On the spurious dissipation of internal waves in ocean circulation models
AU - Shakespeare, Callum J.
AU - Hogg, A. Mc C.
N1 - Publisher Copyright:
© 2006 Australasian Fluid Mechanics Society. All rights reserved.
PY - 2016
Y1 - 2016
N2 - Ocean circulation models employ turbulence closure schemes to represent unresolved sub-gridscale processes, and to maintain model stability. Here we investigate solutions that resolve part of the internal wave spectrum, and show that internal waves generated at boundaries of an ocean model spuriously decay as a result of the artificially high horizontal viscosity and diffusivity typically associated with the turbulence closures. We configure a 200m resolution regional-scale model with a near-inviscid and weakly diffusive interior such that spurious decay of the resolved wave field is minimised, and compare with a significantly more viscous and diffusive configuration as used in previous studies. The reduced viscosity and diffusivity results in an order of magnitude increase in the interior wave energy, with waves sourced from both the ocean surface and bottom propagating over the entire depth of the model ocean with negligible dissipation. The results thus point to the need to re-examine turbulence closures and other parameterisations that may conflict with resolved internal wave dynamics.
AB - Ocean circulation models employ turbulence closure schemes to represent unresolved sub-gridscale processes, and to maintain model stability. Here we investigate solutions that resolve part of the internal wave spectrum, and show that internal waves generated at boundaries of an ocean model spuriously decay as a result of the artificially high horizontal viscosity and diffusivity typically associated with the turbulence closures. We configure a 200m resolution regional-scale model with a near-inviscid and weakly diffusive interior such that spurious decay of the resolved wave field is minimised, and compare with a significantly more viscous and diffusive configuration as used in previous studies. The reduced viscosity and diffusivity results in an order of magnitude increase in the interior wave energy, with waves sourced from both the ocean surface and bottom propagating over the entire depth of the model ocean with negligible dissipation. The results thus point to the need to re-examine turbulence closures and other parameterisations that may conflict with resolved internal wave dynamics.
UR - http://www.scopus.com/inward/record.url?scp=85084015677&partnerID=8YFLogxK
M3 - Conference contribution
T3 - Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016
BT - Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2006
PB - Australasian Fluid Mechanics Society
T2 - 20th Australasian Fluid Mechanics Conference, AFMC 2006
Y2 - 5 December 2016 through 8 December 2016
ER -