6.4.5 Accuracy of stability category estimates

By virtue of its historic precedence and widespread use, EPA considers Turner's method [34] to be the benchmark procedure for determining P-G stability. Evaluations performed in developing the SRDT method indicate that this method identifies the same P-G stability category as Turner’s method (Section 6.4.1) about 60 percent of the time and is within one category about 90 percent of the time (EPA, 1994) [38]. Results are not available comparing the performance of the _A and _E  methods outlined above in this section. However, there are comparison results for similar methods. From these studies, it is concluded that the methods will estimate the same stability category about 50 percent of the time and will be within one category about 90 percent of the time. Readers are cautioned that adjustment of the turbulence criteria resulting from spot checks is necessary to achieve this performance. For additional information on stability classification using wind fluctuation statistics, see references [39], [40], [41], and [42].

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