Mesoscale-Convective Processes in the Atmosphere

This new textbook seeks to promote a deep yet accessible understanding of mesoscale-convective processes in the atmosphere. Mesoscale-convective processes are commonly manifested in the form of thunderstorms, which are fast evolving, inherently hazardous, and can assume a broad range of sizes and severity. Modern explanations of the convective-storm dynamics, and of the related development of tornadoes, damaging 'straight-line' winds and heavy rainfall, are provided. Students and weather professionals will benefit especially from unique chapters devoted to observations and measurements of mesoscale phenomena, mesoscale prediction and predictability, and dynamical feedbacks between mesoscale-convective processes and larger-scale motions. Cover......Page 1 MESOSCALE-CONVECTIVE PROCESSES IN THE ATMOSPHERE......Page 4 ©......Page 5 Contents......Page 6 Preface......Page 8 1.1 Introduction......Page 10 1.2 Historical Perspectives......Page 12 1.3 Atmospheric-Scale Classification Schemes......Page 15 1.4 Mesoscale-Convective Processes......Page 16 2.1.1 Equations......Page 20 2.1.2 Scale Analysis......Page 22 2.1.3 Approximations to the Mass Continuity Equation......Page 25 2.1.4 Inclusion of Moisture......Page 27 2.1.5 Equations for Water Substance......Page 30 2.2 Atmospheric Waves and Oscillations......Page 31 2.2.1 Acoustic Waves......Page 33 2.2.2 Rossby Waves......Page 35 2.2.3 Gravity Waves......Page 36 2.3.1 Gravitational Instability......Page 39 2.3.2 Rayleigh-Bénard Instability......Page 40 2.3.2 Kelvin-Helmholtz Instability......Page 43 2.4 Density Currents......Page 47 Supplementary Information......Page 50 3.1 Introduction......Page 52 3.2.1 Surface......Page 54 3.2.2 Upper-Air Observations......Page 57 3.3 Report-Based Observations of Hazardous Convective Weather......Page 60 3.4.1.1 Overview of Basic Operations......Page 62 3.4.1.2 Retrievals from Multiple Doppler Radars......Page 65 3.4.1.3 Mobile Radar Systems......Page 69 3.4.1.4 Polarimetric Weather Radar......Page 70 3.4.1.5 Wind Profilers......Page 73 3.4.2.1 Overview of Basic Operations......Page 74 3.4.2.2 Radiative Transfer Theory and Satellite Retrievals......Page 76 3.4.2.3 Satellite Applications......Page 80 3.5 Observation Networks......Page 81 3.6.1 Function Fitting......Page 87 3.6.2 Empirical Analysis: Successive Corrections Method......Page 89 Supplementary Information......Page 94 4.1 Introduction......Page 97 4.2.1 Continuous Equations......Page 98 4.2.2 Numerical Approximations......Page 102 4.3.1 Subgrid Scale Turbulence......Page 105 4.3.2 The Land Surface and Atmospheric Boundary Layer......Page 109 4.3.3 Cloud and Precipitation Microphysics......Page 112 4.3.4 Atmospheric Radiation......Page 118 4.3.5 Convective Clouds......Page 119 4.4.1 Initial and Boundary Conditions......Page 121 4.4.2 Data Assimilation......Page 122 4.4.3 Other Design Issues......Page 125 Supplementary Information......Page 127 5.1 Parcel Theory......Page 154 5.2 Synoptic-Scale Conditioning of the Convective Environment......Page 159 5.3 Mechanisms of Local or Near-Field Mesoscale Lift......Page 164 5.3.1 Orographic Lifting......Page 165 5.3.2 Horizontal Convective Rolls......Page 166 5.3.3 Internal Gravity Wave-HCR Interaction......Page 169 5.4.1 Frontogenesis......Page 171 5.4.2 The Dryline......Page 175 5.4.3 The Sea-Breeze Front......Page 180 5.5 Lifting Mechanisms from Nonlocal Sources......Page 182 5.5.1 Convective-Storm Gust Fronts......Page 183 5.5.2 Gravity Waves......Page 187 5.5.3 Atmospheric Bores......Page 190 Supplementary Information......Page 192 6.1 Overview of the Convective Storm Spectrum......Page 195 6.2.1 Updrafts......Page 196 6.2.2 Downdrafts......Page 208 6.3 Convective Outflow......Page 215 6.4 Unicellular Convective Storms......Page 221 6.5 Multicellular Convective Storms......Page 223 Supplementary Information......Page 225 7.1 Characteristics of Supercell Thunderstorms: An Overview......Page 228 7.2 Midlevel Mesocyclogenesis in an Early-Stage Supercell......Page 232 7.3 Supercell Dynamics......Page 236 7.3.2 Case of Curved Hodographs......Page 238 7.3.3 The Linear-Dynamic Pressure Forcing......Page 241 7.3.4 Development of Net Updraft Rotation......Page 245 7.3.5 Storm-Relative Environmental Helicity......Page 246 7.4 Interaction of Wind Field and Precipitation......Page 250 7.5 Low-Level Mesocyclogenesis......Page 252 7.6 Tornadogenesis......Page 256 7.7 Supercell Environment Quantification......Page 261 7.8 Analogues in Tropical Convection: Vortical Hot Towers......Page 262 Supplementary Information......Page 264 8.1 Overview of MCS Characteristics and Morphology......Page 266 8.2.1 The Rotunno-Klemp-Weisman Theory......Page 272 8.2.2 The Rear Inflow......Page 277 8.2.3 The Presence of a Nocturnal Stable Atmospheric Boundary Layer......Page 280 8.2.4 Movement......Page 282 B 8.3.1 Straight-Line Surface Winds from the RIJ......Page 284 8.3.2 Mesovortices (and Related Vortical Topics)......Page 287 8.3.3 Tornadoes......Page 293 8.3.4 Heavy Rainfall and Flash Flooding......Page 294 8.4 Mesoscale Convective Complex......Page 296 8.5 Environments......Page 298 Supplementary Information......Page 300 9.1 Introduction......Page 303 9.2 Boundaries......Page 304 9.3 Mesoscale-Convective Vortices......Page 306 9.4 Interaction between Deep Moist Convection and Synoptic-Scale Dynamics......Page 310 9.5.1 Soil Moisture-Rainfall Feedback......Page 314 9.5.2 Heterogeneities in the Land Surface......Page 318 9.6 Convective Processes and the Global Climate......Page 321 Supplementary Information......Page 325 10.1 Introduction......Page 328 10.2 On Predictability and Its Theoretical Limits......Page 329 10.3 Probabilistic Forecasts and Ensemble Prediction Systems......Page 336 10.4 Forecast Evaluation......Page 338 10.5 Forecast Strategies with Mesoscale Numerical Models......Page 345 10.6 Long-Range Prediction......Page 348 Supplementary Information......Page 353 References......Page 356 Index......Page 376 This Is The First Modern Textbook Devoted Solely To Mesoscale-convective Processes In The Atmosphere. Such Processes Are Realized In The Form Of Thunderstorms And Associated Phenomena. Thunderstorms Are Dynamic And Fast Evolving, And Can Have High Societal Impact. For This Reason It Is Becoming Increasingly Important That Current And Future Generations Of Atmospheric Scientists Have A Deep Understanding Of The Dynamics, Observations, And Prediction Of These Phenomena. The Book Presents In-depth Descriptions Of The Formation, Dynamics, And Qualitative Characteristics Of Convective Phenomena Such As Supercell Thunderstorms And Mesoscale Convective Systems. Although The Descriptions Pertain Largely To The Extratropical Atmosphere, Examples Of Related Tropical Phenomena Are Given For Comparison And Contrast. To Provide A Further Holistic Perspective, Separate Chapters Are Also Included On Mesoscale Observations And Data Analysis, Numerical Modelling, And The Theoretical Predictability And Actual Numerical Prediction Of Mesoscale Weather. An Additional Chapter On Interactions And Feedbacks Addresses Ways In Which Convective Storms Affect And Are Affected By External Processes, Particularly On The Synoptic And Planetary Scale. This Textbook Provides Advanced Students, Researchers And Weather Professionals With A Modern, Accessible Treatment Of The Convective Processes That Lie Within The Range Of The Atmospheric Mesoscale--provided By Publisher. 1. The Atmospheric Mesoscale -- 2. Theoretical Foundations -- 3. Observations And Mesoscale Data Analysis -- 4. Mesoscale Numerical Modeling -- 5. The Initiation Of Deep Convective Clouds -- 6. Elemental Convective Processes -- 7. Supercells: A Special Class Of Long-lived Rotating Convective Storms -- 8. Mesoscale Convective Systems -- 9. Interactions And Feedbacks -- 10. Mesoscale Predictability And Prediction. Robert J. Trapp. Includes Bibliographical References (p. 323-342) And Index. "This is the first modern textbook devoted solely to mesoscale-convective processes in the atmosphere. Such processes are realized in the form of thunderstorms and associated phenomena. Thunderstorms are dynamic and fast evolving, and can have high societal impact. For this reason it is becoming increasingly important that current and future generations of atmospheric scientists have a deep understanding of the dynamics, observations, and prediction of these phenomena. The book presents in-depth descriptions of the formation, dynamics, and qualitative characteristics of convective phenomena such as supercell thunderstorms and mesoscale convective systems. Although the descriptions pertain largely to the extratropical atmosphere, examples of related tropical phenomena are given for comparison and contrast. To provide a further holistic perspective, separate chapters are also included on mesoscale observations and data analysis, numerical modelling, and the theoretical predictability and actual numerical prediction of mesoscale weather. An additional chapter on interactions and feedbacks addresses ways in which convective storms affect and are affected by external processes, particularly on the synoptic and planetary scale. This textbook provides advanced students, researchers and weather professionals with a modern, accessible treatment of the convective processes that lie within the range of the atmospheric mesoscale"-- Résumé de l'éditeur