Atmospheric Turbulence and Air Pollution Modelling

The study of turbulence in the atmosphere has seen considerable progress in the last decade. To put it briefly: boundary-layer meteorology, the branch of atmospheric science that concentrates on turbulence in the lower atmosphere, has moved from the surface layer into the boundary layer itself. The progress has been made on all fronts: theoretical, numerical and observational. On the other hand, air pollution modeling has not seen such a rapid evolution. It has not benefited as much as it should have from the increasing knowledge in the field of atmospheric turbulence. Air pollution modeling is still in many ways based on observations and theories of the surface layer only. This book aims to bring the reader up to date on recent advances in boundary-layer meteorology and to pave the path for applications in air pollution dispersion problems. The text originates from the material presented during a short course on Atmospheric Turbulence and Air Pollution Modeling held in The Hague during September 1981. This course was sponsored and organized by the Royal Netherlands Meteorological Institute, xi xii PREFACE to which both editors are affiliated. The Netherlands Government Ministry of Health and Environmental Protection and the Council of Europe also gave support.

Contenu

1. Equations and Concepts.- 1.1. Introduction.- 1.2. Governing Equations.- 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.- 2. Similarity Relations, Scaling Laws and Spectral Dynamics.- 2.1. Introduction.- 2.2. Rossby-Number Similarity.- 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.- 3.3. Volume-Average Models.- 4. Observed Characteristics of the Atmospheric Boundary Layer.- 4.1. Introduction.- 4.2. Convective Boundary Layer.- 4.3. Stable Boundary Layer.- 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.- 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.- 6.4. Turbulence Diffusion in the Stably-Stratified Atmospheric Boundary Layer.- 6.5. Concluding Remarks.- 7. Applications in Air Pollution Modeling.- 7.1. Introduction.- 7.2. Statistical Models of Diffusion.- 7.3. Improvements to the Gaussian Model.- 7.4. K-Diffusion Models.- 7.5. Progress in the Similarity Theory of Diffusion.- 7.6. Recent Special Applications.- 8. Report from the Panel Discussion.- 9. References.- Authors Index.