6.6.2 The Energy Budget Method

An equation expressing the partitioning of energy at the surface may be used in place of (6.6.5) when measurements of are not available[53, 54, 58]. The expression for the surface energy budget is:

where E is the latent heat flux ( is the latent heat of water vaporization and E is the evaporation rate), Q* is the net radiation and G the soil heat flux. H₀ + E is the energy flux that is supplied to or extracted from the air, while Q* - G is the source or sink for this energy. Using , (6.6.7) can be written as:

In this equation E, Q* and G can be parameterized in terms of the total cloud cover N, the solar elevation , the air temperature T, the friction velocity u_* and _* itself. The idea is to use (6.6.8) to write _* as a function of the variables N,, T, and u_* :

This equation then replaces (6.6.5). The further procedure of finding _* and u_* from (6.6.4) and (6.6.9) by iteration is similar to that used in the profile method.

6. METEOROLOGICAL DATA PROCESSING
  6.1 Averaging and Sampling Strategies 
  6.2 Wind Direction and Wind Speed 
      6.2.1 Scalar Computations 
      6.2.2 Vector Computations 
      6.2.3 Treatment of Calms  
      6.2.4 Turbulence 
      6.2.5 Wind Speed Profiles  
  6.3 Temperature 
      6.3.1 Use in Plume-Rise Estimates  
      6.3.2 Vertical Temperature Gradient 
  6.4 Stability 
      6.4.1 Turner's method  
      6.4.2 Solar radiation/delta-T (SRDT) method 
      6.4.3  _E method 
      6.4.4 _Amethod 
      6.4.5 Accuracy of stability category estimates 
  6.5 Mixing Height 
      6.5.1 The Holzworth Method  
  6.6 Boundary Layer Parameters  
      6.6.1 The Profile Method 
      6.6.2 The Energy Budget Method  
      6.6.3 Surface Roughness Length 
      6.6.4 Guidance for Measurements in the Surface Layer 
  6.7 Use of Airport Data 
  6.8 Treatment of Missing Data  
      6.8.1 Substitution Procedures 
  6.9 Recommendations