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  • the liquid water equivalent of snow lying on the ground
  • the average density of the snow layer (typically lower for fresh uncompacted fresh snow, higher for compacted old snow).

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It is common for snow depth to be extremely high at grid points within points within these areas of permanent snow.  

Fresh snow seems to be too dense and compacted in the model.  As a rough rule of thumb:

  • generally 10mm of precipitation approximates to 10cm of snow depth
  • for less dense newly fallen snow, 10mm of precipitation approximates to 10-15cm of snow depth.
  • with wind effects the density of snow increases quite quickly, 10mm of precipitation approximates to 7cm of snow depth.  
  • very low negative temperatures are required to considerably decrease the density and increase the equivalent snow depth in cm.

The current snow scheme tends to melt snow too slowly.

Snow cover

Snow cover is diagnosed from the water equivalent of the modelled snow: 

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