Transpiration Eυ and bare soil evaporation Eb processes are comparatively analysed assuming homogeneous and inhomogeneous areal distributions of volumetric soil moisture content θ. For a homogeneous areal distribution of θ we use a deterministic model, while for inhomogeneous distributions a statistical-deterministic diagnostic surface energy balance model is applied. The areal variations of θ are simulated by Monte-Carlo runs assuming normal distributions of θ. The numerical experiments are performed for loam. In the experiments we used different parameterizations for vegetation and bare soil surface resistances and strong atmospheric forcing. According to the results the Eυ (θ)-Eb (θ) differences are great, especially in dry conditions. In spite of this, the available energy flux curves of vegetation Aυ (θ) and bare soil Ab (θ) surfaces differ much less than the Eυ (θ) and Eb (θ) curves. The results suggest that Eυ is much more non-linearly related to environmental conditions than Eb. Both Eυ and Eb depend on the distribution of θ, the wetness regime and the parameterization used. With the parameterizations, Eb showed greater variations than Eυ. These results are valid when there are no advective effects or mesoscale circulation patterns and the stratification is unstable.
ASJC Scopus subject areas
- Atmospheric Science