# 2:2.3.3 Sublimation and Evaporation from the Soil

The amount of sublimation and soil evaporation will be impacted by the degree of shading. The maximum amount of sublimation/soil evaporation on a given day is calculated as:

$$E\_s=E'*o\*cov*{sol}$$                                                                                                                                                   2:2.3.7

where $$E\_s$$ is the maximum sublimation/soil evaporation on a given day (mm H$$\_2$$O), $$E'\_o$$ is the potential evapotranspiration adjusted for evaporation of free water in the canopy (mm H$$*2$$O), and $$cov*{sol}$$ is the soil cover index. The soil cover index is calculated

$$cov\_{sol}=exp(-5.0\*10^{-5}\*CV)$$                                                                                                                  2:2.3.8

where $$CV$$ is the aboveground biomass and residue (kg ha$$^{-1}$$). If the snow water content is greater than 0.5 mm H$$\_2$$O, the soil cover index is set to 0.5.

The maximum amount of sublimation/soil evaporation is reduced during periods of high plant water use with the relationship:

$$E'\_s=min\[E\_s,\frac{E\_s\*E'\_o}{E\_s+E\_t}]$$                                                                                                                                         2:2.3.9

where $$E'\_s$$is the maximum sublimation/soil evaporation adjusted for plant water use on a given day (mm H$$\_2$$O), $$E\_s$$ is the maximum sublimation/soil evaporation on a given day (mm H$$\_2$$O), $$E'\_o$$is the potential evapotranspiration adjusted for evaporation of free water in the canopy (mm H$$\_2$$O), and $$E\_t$$ is the transpiration on a given day (mm H$$\_2$$O). When $$E\_t$$ is low $$E'\_s \rightarrow E\_s$$. However, as $$E\_t$$ approaches , $$E'\_o$$,$$E'*s\rightarrow\frac{E\_s}{1+cov*{sol}}$$ .