Effects of insufficient vertical resolution in a 3d coastal ocean model

Abstract

The consequences of not resolving vertical gradients (of velocity or density) in a three- dimensional numerical model are investigated. The results show that the effects of insufficient vertical resolution are significant and can be difficult to discover in complex numerical simulations. Calculations of the vertical wind-driven velocity of the Ekman layer need fine resolution in the upper few meters to avoid an underestmation of the surface velocity and a small overestimation of the velocity below 5-10 m depth. Calculations of upper brackish-layer flow show that an insufficient vertical resolution leads to aqantitative large errors, but in the present experiment, the qualitative errors are modest. Especially in connection with applications involving water quality models and biological models, the errors induced by insufficient vertical resolution can be critical.