Comments on "The differentiation between grid spacing and resolution and their application to numerical modeling"

The comments of Grasso are extended to show that the minimum wavelength tha t is resolved by a numerical model is typically longer than the shortest un filtered wave in the model. This result occurs because the numerical grid i s unable to accurately describe the amplitudes and horizontal derivatives o f short wavelengths in the numerical solution. The numerical scheme may als o introduce phase and dispersion errors that cause short wavelengths to be inaccurate.