Description of the upgrade

A modification of the surface scheme was implemented in order to correct some of the deficiencies of 2m temperature forecast.
  1. The root profile was adjusted. The values of the root percentage in each of the 2 soil layers are now 50% (15%) surface layer, 50% (70%) intermediate layer and a 0% (15%) in the climate layer (percentage values within the brackets are valid for the old scheme). In the absence of precipitation no root extraction is allowed from the climate reservoir.
  2. The background vegetation cover in dry situations was changed. No plant transpiration is allowed if the soil wetness in the root zone is lower than a threshold value. The background vegetation cover is riot decreased linearly to 0 when the root soil wetness decreases to 0.

Implemented: 22 November 1988