Page History

...

• the average elevation above mean sea level (MSL). This is taken from the smoothed model orography.
• the fraction of land. This is used to assess the proportions of each grid square used by HTESSEL and FLake to derive heat, moisture and momentum fluxes. 
• the fractional cover of different vegetation types.   This is used by HTESSEL to derive the different proportions of heat, moisture and momentum fluxes over the land.

...

• these plots do not give a definitive representation of exactly where land and sea grid points lie.  Colour filling is shown up to a coastline rather than by allocation of a grid point as land or sea. For more information see the Land-Sea mask section.
• the relatively coarse representation of orography for sub-seasonal range forecasts.
• sea depth can be useful for explaining sea-surface temperature changes.  Model (and indeed real) sea ice cover and sea-surface temperatures tend to change more rapidly where the ocean is shallow.  This is because less energy is generally required to achieve a change in temperature.

...

• smooth true orography, particularly in rugged mountainous areas where there are large variations in altitude over short distances.  Mountain peaks may be under-represented and narrow valleys may not be represented at all. See example at Fig9.2.1.1-5 in orography effects.
• local effects can be under-identified where there are small scale variations in true or model orography, even where relatively low in altitude. 
• lead to "topographic ripples" over adjacent sea/large lakes, which decay with offshore distance, and which are most prominent where there are steep-sided high mountains nearby.

See also selection of grid points for meteograms and selection of grid points for vertical profiles.  See the selection methods directly compared.

(FUG Associated associated with Cy50r1)