Figure 9. Comparison of the resolution over much of North America for a GCM with triangular spectral truncations when using a grid of (a) 5.6 x 5.6 deg. (T21), (b) 2.8 x 2.8 deg. (T42), (c) 1.9 x 1.9 deg. (T63), and (d) 1.1 x (1.1) deg. (T106). Respectively, these resolutions represent roughly the grids used for early climate change calculations, for present leading edge calculations, for resolutions expected to be used for climate simulations within ~ 5 years, and for resolutions used by the national weather services to simulate the regional details of the weather that are determined to a large extent by the orography [Source: PCMDL/LLNL].