Bulk transfer equations for heat and mass transfer from surfaces are very useful in land surface models due to their simple formulation. However, vegetation surfaces introduce several complications for their use because of their effects on turbulent transfer and on the temperature profile within the canopy. Some of these problems may be mitigated by producing a scalar roughness for use bulk transfer equations which accounts for processes within the canopy.
The objective of this proposed research is to model canopy temperature profiles and their effects on the bulk transfer equations, and to develop simple empirical equations to determine the canopy temperature profile characteristics without the use of complex multi-layer canopy models.
The methods to be employed will be to first employ a multi-layer radiative transfer model to conduct a sensitivity analysis of the factors, which affect the canopy temperature profile. These include solar elevation, turbulence and radiation intensity, soil moisture and canopy density and structure. The radiative transfer model and the methods employed to estimate the scalar roughness would be validated by means of intensive canopy temperature profile measurements.
The significance of the proposed activities is that they will develop a method to deal with vegetated surfaces in Land surface models and weather models without having to incorporate complex canopy models. The results should improve the output from weather prediction models.
