The relationship between the spectral truncation, T, the number of grid points used to represent the shortest wave (i.e. linear, quadratic or cubic) and the grid point resolution, N, allows for three possible approaches for increasing the horizontal resolution:

- increase the number of wave numbers in the spectral representation but keep the same Gaussian grid by reducing the number of grid points used to represent the shortest wave (i.e., increase T with T
_{Q}→T_{L}keeping N constant); - increase the number of wave numbers in the spectral representation and the Gaussian grid resolution but keep the number of grid points used to represent the shortest wave constant (i.e. increase T and increase N).
- keep the number of wave numbers in the spectral representation constant and increase the Gaussian grid resolution by increasing the number of grid points used to represent the shortest wave (i.e., T
_{L}→T_{C}, and increase N).