Atmospheric Turbulence Air Pollution Modelling

1. Equations and Concepts.- 1.1. Introduction.- 1.2. Governing Equations.- The Equations of Continuity.- The Equation of State.- Potential Temperature.- The Equations of Motion.- Conservation of Enthalpy.- Conservation of Transferable Scalar Quantities.- 1.3. Equations of the Mean Flow.- 1.4. Discussion of the Boussinesq Approximations and the Conservation of Enthalpy Equation.- 1.5. Summary of the Boussinesq Set of Equations.- 1.6. The Closure Problem, First-Order Closure.- 1.7. Second-Order Variance and Covariance Equations.- 1.8. The Turbulent Kinetic Energy Balance; Temperature Variance Balance.- Appendix A. Requirements for a Divergence-Free Velocity Field.- Appendix B. The magnitude of Pressure Fluctuations.- Appendix C. The Enthalpy Equation for Moist Air.- Appendix D. The Ekman Spiral.- 2. Similarity Relations, Scaling Laws and Spectral Dynamics.- 2.1. Introduction.- 2.2. Rossby-Number Similarity.- The Surface Layer.- The Process of Matching.- The Constant-Stress Layer.- The Von Karman Constant.- 2.3. Diabatic Extension of Rossby-Number Similarity.- 2.4. Monin-Obukhov Similarity in the Surface Layer.- 2.5. Scaling of Turbulence Quantities in the Surface Layer.- 2.6. Scaling of Turbulence Outside the Surface Layer.- 2.7. Correlation Functions and Spectra.- 2.8. Inertial Subranges.- 3. Boundary-Layer Modeling.- 3.1. The calculation of boundary-layer structure.- 3.2. Ensemble-average models.- First-Order or Eddy-Diffusivity (K) Closure.- Second-Order Closure.- 3.3. Volume-Average Models.- Large-Eddy Models.- Other Volume-Average Models.- 4. Observed Characteristics of the Atmospheric Boundary Layer.- 4.1. Introduction.- 4.2. Convective Boundary Layer.- Boundary-Layer Development.- Spectra of the Velocity Components.- Spectrum of Temperature.- Cospectra of Heat Flux and Stress.- Entrainment.- Variances, Dissipation Rates and Structure Parameters.- Turbulent Kinetic Energy Budget.- 4.3. Stable Boundary Layer.- General Characteristics of the SBL.- Waves and Turbulence.- Turbulence Spectra in the Stable Surface Layer.- Turbulence Behavior through the SBL Depth.- Depth of the SBL.- 4.4. Concluding Remarks.- 5. Diffusion in the Convective Boundary Layer.- 5.1. Introduction.- 5.2. Formulation of a Lagrangian Diffusion Model.- 5.3. Numerical Simulations of Non-Buoyant Material Diffusion and Comparisons With Observations.- Results.- Comparison of the Model Results with.- Observations.- 5.4. The Structure of Turbulence in the Convective Boundary Layer.- 5.5. Formulas for Application.- 5.6. Dispersion of Buoyant Emissions in a Convective Boundary Layer.- 6. Diffusion in the Stable Boundary Layer.- 6.1. Introduction.- 6.2. Basic Ideas about Molecular and Fluid Element Motion and Probability Distributions.- 6.3. Turbulent Diffusion in Idealized Flows.- Marked Fluid Elements in Unstratified Turbulence Away from Boundaries.- Unidirectional shear flow.- Straining flow.- Flux gradient relations - when are they likely to go wrong?.- Diffusion in Stably-Stratified Turbulence.- 6.4. Turbulence Diffusion in the Stably-Stratified Atmospheric Boundary Layer.- Some Properties of the Stably Stratified.- Atmospheric Boundary Layer.- Mean velocity profile.- Mean temperature profile.- Vertical turbulence and heat flux.- Horizontal components of turbulence.- Turbulence at heights of 50 to 300 m.- Diffusivities and temperature fluctuations.- Elevated Source above the Surface Layer.- Sources in the Surface Layer.- Elevated sources in the surface layer (t < TL).- Elevated sources in the surface layer (t > TL).- Comparison of vertical diffusion from ground-level and elevated sources.- 6.5. Concluding Remarks.- Concentration Distributions.- Complex Atmospheric Conditions.- Topography.- 7. Applications in Air Pollution Modeling.- 7.1. Introduction.- 7.2. Statistical Models of Diffusion.- Taylor's Statistical Theory.- Monte Carlo Diffusion Models.- Model description.- Turbulent energy and Lagrangian time scales in the unstable PBL.- Turbulent energy and Lagrangian time scales in the stable PBL.- Turbulent energy and Lagrangian time scales in the neutral PBL.- Results of application of the Monte Carlo model.- The Langevin Horizontal Diffusion Model.- 7.3. Improvements to the Gaussian Model.- Wind Speed in the Gaussian Plume Model.- Plume Rise Calculations.- Estimation of ?y and ?z using ?? and ?e.- Determination of Stability Class.- Revisions of Pasquill-Gifford (P-G) Sigma Curves.- 7.4. K-Diffusion Models.- Analytical Solutions to the Diffusion Equation.- Numerical Solutions to the Diffusion Equation.- 7.5. Progress in the Similarity Theory of Diffusion.- 7.6. Recent Special Applications.- Skewness of Vertical Turbulent Velocity.- Natural Variability of Pollutant Concentrations.- Representativeness of Wind-Speed Observations.- 8. Report from the Panel Discussion.- 9. References.- Authors Index.