- Director's Message
- Table of Contents
- Strategic Goals: Science, Facilities & Technology
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Strategic Goal #1, Strategic Priority #1:
Exploring atmospheric, Earth System, and solar processes, variability, and change -
Strategic Goal #1, Strategic Priority #2:
Investigating the interaction of the atmosphere, the broader Earth system, and human society -
Strategic Goal #1, Strategic Priority #3:
Improving prediction of weather, climate, and other atmospheric phenomena -
Strategic Goal #1, Strategic Priority #4:
Developing community models -
Strategic Goal #5, Strategic Priority #1:
Enabling innovative field experiments and measurement campaigns -
Strategic Goal #5, Strategic Priority #2:
Developing new instrumentation
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Strategic Goal #1, Strategic Priority #1:
- Research Catalog
CGD's Dr. Peter Gent
McDougall, T.J., P. R. Gent, and S. Drijfhout, 2007a. Comment on "Dynamical model of mesoscales in z-coordinates" and "The effect of mesoscales on the tracer equation in z-coordinates OGCMs" by V M Canuto and M S Dubovikov. Ocean Modelling, 17, 163-171.
Abstract
Canuto and Dubovikov (2006a, 2006b) claim that present oceanographic models ignore a leading-order diapycnal term in the mean buoyancy and tracer equations, while previously published work shows this is not the case. It is important for the density and tracer equations of ocean models to be diabatic only to the extent of imposed diapycnal mixing. Present ocean modelling practice does achieve this property but the equations and parameterizations of Canuto and Dubovikov do not. Canuto and Dubovikov also argue that the same "missing" term in the mean buoyancy equation leads to extra diapycnal advection across mean isopycnals that should be included in the diapycnal advection-diffusion balance in the deep ocean. We show that this is incorrect: the relevant mean diapycnal advection of the Munk-Wunsch advective-diffusive balance is caused by small-scale mixing processes and processes due to the non-linear nature of the equation of state, not by the four so-called "mesoscale-adiabatic" terms identified by Canuto and Dubovikov.
Support: National Science Foundation.
McDougall, T. J., P. R. Gent, and S. Drijfhout, 2007b. Comment on "Complete Eulerian-mean tracer equation for coarse resolution OGCMs" by M S Dubovikov and V M Canuto. Geophysical and Astrophysical Fluid Dymanics, In Press.
Abstract
Dubovikov and Canuto (2006), after averaging the tracer conservation equation in density coordinates and transforming to height coordinates, concluded that present ocean models are missing important terms in their mean tracer equations. Here we point out some errors made by Dubovikov and Canuto (2006) in their isopycnal averaging procedure. We draw on the temporal-residual-mean (TRM) theory and show that when the isopycnal averaging and coordinate transformation are performed correctly, the tracer equations of present ocean circulation models are recovered. We therefore conclude that present ocean circulation models are not neglecting the leading order terms identified by Dubovikov and Canuto (2006).
Support: National Science Foundation.