Abstract We describe a simple, flux conserving robust advection scheme that reduces numerical dispersion in application to passive scalar advection. Our hydrostatic semi-collocated (modified Arakawa ‘a’ grid) ocean model performance is enhanced by this modification in combination with a modified strategy for incompressibility. The modified advection scheme also reduces overshooting errors resulting from numerical dispersion in the evolution of a sloshing front using a non-hydrostatic model. In Gulf of Mexico simulations, many of the realistic detailed features from our original model using 1/12° (about 9 km) resolution occur using the modified numerics with 20-km resolution. These are not seen with the original numerics and 20-km resolution. These detailed features include: strong fronts and frontal eddies; many cyclonic eddies, which spin off major warm core Loop Current eddies; and sharp eastward deflection of the Loop Current directly into the Florida Strait after major warm core eddy shedding.
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