Mesoscale Dynamics

Mesoscale weather systems are responsible for numerous natural disasters, such as damaging winds, blizzards and flash flooding. A fundamental understanding of the underlying dynamics involved in these weather systems is essential in forecasting their occurrence. This 2007 book provides a systematic...

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Bibliographic Details
Main Author Lin, Yuh-Lang
Format eBook
LanguageEnglish
Published Cambridge Cambridge University Press 13.12.2007
Edition1
Subjects
Mesoscopic phenomena (Physics)
Mesospheric circulation
Mesospheric thermodynamics
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Table of Contents:
  • Cover -- MESOSCALE DYNAMICS -- Title -- Copyright -- Contents -- Preface -- 1 Overview -- 1.1 Introduction -- 1.2 Definitions of atmospheric scales -- 1.3 Energy generation and scale interactions -- 1.4 Predictability -- References -- 2 Governing equations for mesoscale motions -- 2.1 Introduction -- 2.2 Derivation of the governing equations -- 2.3 Approximations to the governing equations -- References -- Problems -- 3 Basic wave dynamics -- 3.1 Introduction -- 3.2 Basic wave properties -- 3.3 Sound waves -- 3.4 Shallow water waves -- 3.5 Pure gravity waves -- 3.6 Inertia-gravity waves -- 3.7 Wave reflection levels -- 3.8 Critical levels -- Appendix 3.1 Derivations of shallow-water equations -- References -- Problems -- 4 Mesoscale wave generation and maintenance -- 4.1 Introduction -- 4.2 Wave generation mechanisms -- 4.2.1 Density impulses and moist convection -- 4.2.2 Mesoscale instabilities -- 4.2.3 Geostrophic adjustment -- a. Inertia-gravity wave generation through geostrophic adjustment -- b. Diagnosis for unbalanced flow -- 4.2.4 Nonlinear interactions -- 4.3 Wave maintenance mechanisms -- 4.3.1 Linear wave ducting mechanism -- 4.3.2 Solitary wave mechanism -- 4.3.3 Wave-CISK mechanism -- 4.4 Energy propagation and momentum flux -- References -- Problems -- 5 Orographically forced flows -- 5.1 Flows over two-dimensional sinusoidal mountains -- 5.2 Flows over two-dimensional isolated mountains -- 5.2.1 Uniform basic flow -- 5.2.2 Basic flow with variable Scorer parameter -- 5.2.3 Trapped lee waves -- 5.3 Nonlinear flows over two-dimensional mountains -- 5.3.1 Nonlinear flow regimes -- 5.3.2 Generation of severe downslope winds -- a. Resonant amplification theory -- b. Hydraulic theory -- c. Applications of resonant amplification and hydraulic theories -- 5.4 Flows over three-dimensional mountains -- 5.4.1 Linear theory
  • b. Cloudy atmosphere
  • 7.2.3 Howard's semicircle theorem -- 7.3 Static, conditional, and potential instabilities -- 7.3.1 Static instability -- 7.3.2 Conditional instability -- 7.3.3 Potential instability -- 7.4 Kelvin-Helmholtz instability -- 7.5 Inertial instability -- 7.6 Symmetric instability -- 7.6.1 Dry symmetric instability -- 7.6.2 Moist symmetric instability -- 7.7 Baroclinic instabiltity -- References -- Problems -- 8 Isolated convective storms -- 8.1 Dynamics of single-cell storms and downbursts -- 8.2 Dynamics of multicell storms -- 8.3 Effects of shear and buoyancy -- 8.3.1 Effects of shear on cold outflow -- 8.3.2 Effects of buoyancy -- 8.4 Dynamics of supercell storms -- 8.4.1 General characteristics -- 8.4.2 Effects of unidirectional shear -- 8.4.3 Storm splitting -- 8.4.4 Storm rotation and propagation -- 8.4.5 Effects of directional shear -- 8.5 Tornado dynamics -- 8.5.1 Supercell tornadogenesis -- 8.5.2 Nonsupercell tornadogenesis -- 8.5.3 Tornado vortex dynamics -- References -- Problems -- 9 Mesoscale convective systems -- 9.1 Squall lines and rainbands -- 9.1.1 Squall line classifications -- 9.1.2 Formation mechanisms -- 9.1.3 Maintenance mechanisms -- a. Three-dimensional effects -- b. Gravity wave mechanism -- c. Local balance mechanism -- 9.1.4 Squall line movement -- 9.1.5 Rainbands -- 9.2 Mesoscale convective complexes -- 9.2.1 General characteristics -- 9.2.2 Formation and development mechanisms -- 9.3 Tropical cyclones -- 9.3.1 General characteristics -- 9.3.2 Tropical cyclogenesis -- a. Cooperative intensification mechanism -- b. Linear CISK mechanism -- c. WISHE mechanism -- d. Vortex interaction mechanism -- e. Hot-tower mechanism -- f. Preexisting disturbances and a unified mechanism for tropical cyclogenesis -- g. Control parameters of tropical cyclogenesis -- h. Extratropical hurricanes -- 9.3.3 Intensity and mesoscale structure
  • 12.1 Introduction -- 12.2 Finite difference approximations of derivatives -- 12.3 Finite difference approximations of the advection equation -- 12.3.1 Two-time-level schemes -- (a) Forward-in-time and centered-in-space scheme -- (b) Forward-in-time and upstream-in-space scheme -- (c) Lax-Wendroff scheme -- 12.3.2 Three-time-level schemes -- (a) Adams-Bashforth scheme -- 12.4 Implicit schemes -- 12.5 Semi-Lagrangian methods -- Appendix 12.1: -- References -- Problems -- Modeling projects -- Project A -- Project B -- 13 Numerical modeling of geophysical fluid systems -- 13.1 Grid systems and vertical coordinates -- 13.1.1 Grid systems -- 13.1.2 Vertical coordinates -- 13.2 Boundary conditions -- 13.2.1 Lateral boundary conditions -- 13.2.2 Upper boundary conditions -- 13.2.3 Lower boundary conditions -- 13.3 Initial conditions and data assimilation -- 13.4 Nonlinear aliasing and instability -- 13.5 Modeling a stratified fluid system -- 13.6 Predictability and ensemble forecasting -- References -- Problems -- Modeling projects -- 14 Parameterizations of physical processes -- 14.1 Reynolds averaging -- 14.2 Parameterization of planetary boundary layer processes -- 14.2.1 Parameterization of the surface layer -- 14.2.2 Parameterization of the PBL -- a. Bulk aerodynamic parameterization -- b. K-theory parameterization -- c. Turbulent kinetic energy closure scheme -- d. Higher-order closure schemes -- 14.3 Parameterization of moist processes -- 14.3.1 Parameterization of microphysical processes -- a. Explicit representation -- b. Bulk microphysics parameterization -- 14.3.2 Cumulus parameterization -- a. Convective adjustment schemes -- b. Kuo schemes -- c. Cumulus parameterization schemes for mesoscale models -- 14.4 Parameterizations of radiative transfer processes -- 14.4.1 Introduction -- 14.4.2 Longwave radiation -- a. Clear atmosphere
  • 5.4.2 Generation of lee vortices -- a. Boundary layer separation -- b. Generation of lee vortices in an inviscid fluid -- c. Tilting of baroclinically generated vorticity -- d. Generation of potential vorticity by turbulence dissipation -- 5.5 Flows over larger mesoscale mountains -- 5.5.1 Rotational effects -- 5.5.2 Lee cyclogenesis -- a. Alpine lee cyclogenesis -- b. Rockies lee cyclogenesis -- c. Mesoscale lee cyclogenesis -- 5.5.3 Orographic influence on cyclone track -- 5.6 Other orographic effects -- 5.6.1 Effects on frontal passage -- 5.6.2 Coastally trapped disturbances -- 5.6.3 Cold-air damming -- 5.6.4 Gap flow -- Appendix 5.1: Some mathematical techniques and relations -- (a) Fourier Transform -- (b) Jordan's Lemma -- (c) Riemann-Lebesgue Lemma -- (d) Parseval Theorem -- References -- Problems -- 6 Thermally forced flows -- 6.1 Two-dimensional flows -- 6.1.1 Steady flows over a sinusoidal heat source -- 6.1.2 Steady flows over an isolated heat source -- 6.2 Transient flows -- 6.2.1 Flow responses to pulse heating -- 6.2.2 Flow responses to steady heating -- 6.3 Applications to mesoscale circulations -- 6.3.1 Density current formation and propagation -- 6.3.2 Heat island circulations -- 6.3.3 Moist convection -- 6.3.4 Gravity wave generation and propagation -- 6.4 Effects of shear, three dimensionality, and rotation -- 6.4.1 Two-dimensional shear flows -- 6.4.2 Three-dimensional nonrotating flows -- 6.4.3 Three-dimensional rotating flows -- 6.5 Dynamics of sea and land breezes -- 6.5.1 Linear theories -- 6.5.2 Nonlinear numerical studies -- 6.6 Dynamics of mountain-plains solenoidal circulations -- Appendix 6.1: Laplace transform -- References -- Problems -- 7 Mesoscale instabilities -- 7.1 Wave energy transfer through instabilities -- 7.2 Integral theorems of stratified flow -- 7.2.1 Governing equations -- 7.2.2 Miles' theorem
  • a. Intensity of a mature tropical cyclone -- b. Mesoscale structure of a tropical cyclone -- 9.3.4 Tropical cyclone movement -- References -- Problems -- 10 Dynamics of fronts and jet streaks -- 10.1 Kinematics of frontogenesis -- 10.2 Dynamics of two-dimensional frontogenesis -- 10.2.1 Geostrophic momentum approximation -- 10.2.2 Frontogenesis and cross-frontal circulations -- 10.3 Frontogenesis and baroclinic waves -- 10.4 Moist and frictional effects on frontogenesis -- 10.5 Other types of fronts -- 10.5.1 Upper-level frontogenesis -- 10.5.2 Drylines -- 10.6 Jet streak dynamics -- 10.6.1 Upper-level jet streaks -- a. General characteristics of a jet streak -- b. Vertical motion associated with a jet streak -- c. Formation and propagation of a jet streak -- d. Interaction of jet streak circulations -- 10.6.2 Low-level jets -- a. Inertial oscillation -- b. Baroclinic effects -- c. Orographic deflection -- d. Synoptic forcing -- e. Diabatic processes -- References -- Problems -- 11 Dynamics of orographic precipitation -- 11.1 Orographic influence on climatological distribution of precipitation -- 11.2 Orographic modification of preexisting disturbances -- 11.2.1 Passage of troughs -- 11.2.2 Passage of midlatitude cyclones and fronts -- 11.2.3 Passage of tropical cyclones -- 11.2.4 Common ingredients of orographic precipitation -- 11.3 Formation and enhancement mechanisms -- 11.3.1 Stable ascent mechanism -- 11.3.2 Release of moist instabilities -- 11.3.3 Effects of mountain geometry -- 11.3.4 Combined thermal and orographic forcing -- 11.3.5 Seeder-feeder mechanism -- 11.3.6 Dynamical-microphysical interaction mechanism -- 11.4 Control parameters and moist flow regimes -- 11.4.1 Control parameters -- 11.4.2 Moist flow regimes -- (a) Two-dimensional flow regimes -- (b) Three-dimensional flow regimes -- References -- 12 Basic numerical methods