Atmospheric Convection

This graduate-level meteorology text and reference provides a scientifically rigorous description of the many types of convective circulations in the Earth's atmosphere. These range from small-scale, convectively driven turbulences in the boundary layer to precipitating systems covering many thousands of square kilometers. The text introduces the principal techniques used in understanding and predicting convective motion: theory, field experiment, and numerical modelling. Part I explores dry convection, including turbulent plumes and thermals from isolated buoyancy sources, Raleigh-Benard convection, and turbulent convection in the planetary boundary layer. Emphasis is placed on applying theoretical understanding and lessons from experiments. Part II offers a complete treatment of the thermodynamics of moist and cloudy air, including fundamental laws, conserved quantities, graphical techniques, and stability. Part III explores the characteristics of individual convective clouds, thunderstorms, squall lines, mesoscale convective systems, and slantwise convection. Part IV studies the ensemble effects of convective clouds, including stratocumulus at trade cumulus boundary layers and the representation of convective clouds in numerical models. Each chapter is followed by a set of exercises. Pt. I. Dry Convection. 1. General Principles. 1.1. Definition Of Convection. 1.2. The Buoyancy Force. 1.3. The Boussinesq And Anelastic Approximations. 2. Convection From Local Sources. 2.1. The Similarity Approach And Definitions Of Thermals And Plumes. 2.2. Turbulent Plumes Originating From A Maintained Point Source. 2.3. Turbulent Plumes Originating From A Maintained Line Source. 2.4. Turbulent Convection From An Instantaneous Point Source (thermals). 2.5. Turbulent Starting Plumes. 2.6. Laminar Plumes Originating From A Maintained Point Source. 2.7. Turbulent Convection In Stably Stratified Fluid. 2.8. Experiments And Observations. 3. Global Convection: The Rayleigh-benard Problem And Dry Convective Boundary Layers. 3.1. Linear Stability Analysis Of Rayleigh Convection: The Original Rayleigh Problem. 3.2. Parallel-plate Convection With Insulating Boundaries. 3.3. Inclusion Of Rotational Effects. 3.4. Parallel-plate Convection In Shear Flows. 3.5. Nonlinear Parallel-plate Convection. 3.6. Convective Boundary Layers -- Pt. Ii. Moist Thermodynamics And Stability. 4. Moist Thermodynamic Processes. 4.1. Moisture Variables. 4.2. Thermodynamics Of Unsaturated Moist Air. 4.3. Virtual And Density Temperatures. 4.4. Phase Equilibrium Of Water Substance. 4.5. Conserved Moist Thermodynamic Variables. 4.6. Processes Leading To Saturation In The Atmosphere. 4.7. Reversible And Pseudoadiabatic Processes. 4.8. Microphysical Considerations. 4.9. Thermodynamics Of The Ice Phase. 5. Graphical Techniques. 5.1. Thermodynamic Diagrams. 5.2. Conserved-variable Diagrams. 6. Stability. 6.1. Static Stability Of Moist, Unsaturated Air. 6.2. Static Stability Of Cloudy Air. 6.3. Stability To Finite-amplitude Displacements: The Parcel Method. 6.4. Stability Diagrams. 6.5. The Slice Method 6.6. Available Potential Energy Of Barotropic Moist Atmospheres. 6.7. Remarks On Conditional Versus Potential Instability -- Pt. Iii. Local Properties Of Moist Convection. 7. Observed Characteristics Of Nonprecipitating Cumuli. 7.1. Measurement Of Clouds. 7.2. Kinematic Structure Of Nonprecipitating Cumuli. 7.3. Distributions Of Cloud Water, Temperature, And Mixing Ratio In Nonprecipitating Cumuli. 7.4. Inferences About Entrainment And Mixing From Conserved-variable Diagrams. 7.5. Organization Of Nonprecipitating Cumuli. 8. Theory Of Mixing In Cumulus Clouds. 8.1. Instabilities Of Cloud-clear Air Interfaces. 8.2. Velocity And Length Scales Associated With Mixing In Cumuli. 9. Observed Characteristics Of Precipitating Convection. 9.1. The Common Convective Shower And Thunderstorm. 9.2. Intense Convective Storms. 9.3. Squall Lines. 9.4. Cloud Clusters And Mesoscale Convective Complexes. 10. Numerical Modeling Of Convective Clouds. 10.1. General Considerations. 10.2. Basic Equations Suitable For Cloud Models. 10.3. Representation Of Subgrid-scale Motions. 10.4. Representation Of Cloud Microphysical Processes. 10.5. Boundary And Initial Conditions. 10.6. An Example Of A Numerical Simulation. 11. Dynamics Of Precipitating Convection. 11.1. The Response Of Stratified Fluids To Heat Sources. 11.2. Deep Convective Scales And Quasi-equilibrium Versus Triggered Convection. 11.3. Dynamic Effects Of Falling Precipitation. 11.4. Nonlinear Dynamics Of Squall Lines. 11.5. Dynamics Of Three-dimensional Precipitating Convection. 11.6. Classification Of Precipitating Convection. 12. Slantwise Convection. 12.1. Centrifugal Convection. 12.2. Theory Of Slantwise Convection. 12.3. Observational Evidence Of Slantwise Convection -- Pt. Iv. Global Moist Convection. 13. Stratocumulus And Trade-cumulus Boundary Layers. 13.1. Fog. 13.2. Equilibrium Mixed Layers. 13.3. Stratocumulus-topped Mixed Layers. 13.4. Trade-cumulus Boundary Layers. 14. Deep Convective Regimes. 14.1. Thermodynamic Structure. 14.2. Quasi-equilibrium. 15. Interaction Of Convection With Large-scale Flows. 15.1. Effect Of Moist Convection On Large-scale Variables. 15.2. Properties Of Convective Ensembles Deduced From Atmospheric Sounding Arrays. 15.3. Elementary Aspects Of The Interaction Between Convection And Large-scale Atmospheric Circulations. 16. Cumulus Representation In Numerical Models. 16.1. General Considerations. 16.2. Convective Representations Based On Moisture Budgets. 16.3. Adjustments Schemes. 16.4. Penetrative Convection Schemes Based On Cloud Models. 16.5. Validation Of Convective Representations -- Appendix 1. Water And Thermodynamic Variables. Kerry A. Emanuel. Includes Bibliographical References And Index. Atmospheric Convection is a scientifically rigorous description of the multitude of convective circulations in the Earth's atmosphere, ranging from small-scale convectively driven turbulence in the boundary layer to non-precipitating "trade wind" cumuli to precipitating convective systems covering many tens of thousands of square kilometres.