An Introduction to Planetary Atmospheres

Transcription

1 An Introduction to Planetary Atmospheres Agustin Sandiez-Lavepa University of the Basque Country CRC Press Taylor & Francis Group Boca Raton London NewYork CRC Press is an imprint of the Taylor & Francis Croup, an informa business A TAYLOR&FRANCISBOOK

2 Contents Preface Acknowledgments Author List of Tables List of Symbols xix xxiii xxv xxvii xxxi Chapter 1 Introduction to Planets and Planetary Systems Planetary Systems Solar System Planets Orbital Motion Basics of Orbital Mechanics Newton's Law of Universal Gravitation Motion under a Central Conservative Force Kepler's Laws of Planetary Motion The Motion of Two Bodies under Their Mutual Gravitational Attraction Three-Body Problem Orbital Perturbations and Resonances Gravitational Field and the Shape of Planets and Major Satellites Gravitational Field of a Planet Gravitational Tidal Force and Torque Roche's Limit Planetary Rotation System and Coordinates Primary Energy Sources on Planets Rotational Mechanical Energy Internal Energy Radioactive Decay Gravitational Energy Tidal Heating External Energy Global Insolation Insolation in a Planet or Satellite Albedo Equilibrium and Effective Temperatures Internal Structure of Planets and Satellites Equation of State Density Profiles 41 vii

3 viii Contents Mass-Radius Relationship Energy Transport in the Planetary Body Conduction Radiation Convection Planetary Structure: Internal Differentiation of Solid Bodies Magnetic Field Maxwell Equations Dynamo Regime Dipole Field Magnetic Fields in Solar System Bodies Planetodiversity 60 Problems 64 Chapter 2 Origin and Evolution of Planetary Atmospheres Origin of the Solar System Thermal Evolution of the Planets Origin of Planetary Atmospheres Elemental Abundances and Isotopic Ratios Outgassing Processes Capture Processes Overview of the Origin of Primordial Atmospheres for Each Body Atmospheric Evolution Processes Erosion and Escape Processes Thermal or Jeans Escape Nonthermal or Photochemical Escape Hydrodynamical or "Blowoff" Escape Geometrical "Blowoff" Escape Impacts and Collisions Surface Processes Condensation Adsorption Dissolution Chemical Weathering Atmospheric Feedbacks Biological Processes Solar (Stellar) Luminosity Variability Orbital Cycles Variability of the Earth's Atmosphere LossofC The Rise of Oxygen 101

4 Contents ix Snowball Earth Catastrophic Impacts Ice Ages (Glaciations) Warm Periods Last Millennia Climate and Modern Times: "Climate Change" Global Warming Pollution Acid Rain Ozone Hole Observed Atmospheric Changes in Other Planets Venus Mars Solar System Giants and Extrasolar Planets Titan Ill Problems Ill Chapter 3 Spectroscopy and Composition Atmospheric Composition: Fundamentals Planetary Spectrum: The Continuum Reflected Spectrum Thermal Spectrum Atomic Spectrum Atomic Structure: Basics Line Profiles Collision or Pressure Broadening Doppler Broadening Voigt Broadening Equivalent Width, Transmittance, and the Curve of Growth Molecular Spectrum Vibrational Energy Levels Rotational Energy Levels Vibration-Rotation Bands Special Cases Overtones Bands Inversion Bands Collision-Induced Absorptions and Quadrupolar Electric Transitions Band Transmittance, Absorptance, and Equivalent Width Band Models The Correlated-Л Approximation Atmospheric Composition Definitions 153 Problems 160

5 X Contents Chapter 4 Vertical Temperature Structure Vertical Structure of the Atmospheres Hydrostatic Equilibrium: Pressure and Density Scale Heights Observed Temperature Structure Venus Earth Mars Titan Jupiter, Saturn, Uranus, and Neptune Radiative Transfer Radiative Transport: Definitions Equation of Radiative Transfer Source Function Independent of the Optical Depth Purely Absorbing Medium Local Thermodynamic Equilibrium Absorption and Emission Lines under LTE Radiative Equilibrium in Atmospheres Vertical Temperature Profile in Radiative Equilibrium Greenhouse Effect Heating Rates Radiative Time Constant Radiative Temperature: Temporal Variability Thermal Tides: Temperature Oscillations Adiabatic Lapse Rate Thermodynamics: Adiabatic Lapse Rate Potential Temperature Potential Temperature and the Brunt-Väisälä Frequency 202 Problems 207 Appendix 4.A 212 Chapter 5 Clouds in Planets Chemistry and Surface Processes Chemical Equilibrium Basics of Chemical Equilibrium More Detailed Thermochemical Equilibrium Surface-Troposphere Cycles of Condensable Gases and Aerosols Venus Earth 232

6 Contents xi Mars Titan Clouds Properties Moisture Variables and Definitions Latent Heat and the Clausius-Clapeyron Equation Condensation Level and Cloud Formation Cloud Density and Vertical Extent Wet Adiabatic Lapse Rate Equivalent Potential Temperature and Conditional Instability Conditional Instability Microphysics Growth of Cloud Particles: Nucleation Diffusion: Condensation-Evaporation- Sublimation Collision and Coalescence Sedimentation Size and Shape Distribution Radiative Transfer in Clouds Definitions Gas Absorption and Scattering Gas Absorption: A Useful Simple Approach Rayleigh Scattering Particle Absorption and Scattering (Mie Scattering) The Radiative Transfer Equation Including Particulates Purely Absorbing Atmosphere Infrared Intensity: Thermal Radiation and the Temperature Profile Single-Scattering Approximation Isotropic Scattering Thick Clouds Reflectivity Laws Cloud Forcing and Aerosol Heating Rates Observed Cloud Properties: Overview 275 Problems 286 Chapter 6 Upper and Tenuous Atmospheres Upper Atmospheres: Introduction Photochemistry Fundamentals Applications to Terrestrial and Giant Planets, Titan, Triton, and Pluto 299

7 xii Contents Earth Venus Mars Titan Giant Planets Triton and Pluto Photoionization: Ionospheres Ionization by Photons Planetary Ionospheres Earth Venus and Mars Giant Planets Titan Electrical Properties Upper Atmospheres Heating Balance Diffusion Processes Molecular Diffusion Eddy Diffusion Diffusion Processes in Planetary Atmospheres Airglow and Aurora Airglow Aurora Gas Production Mechanisms in Tenuous Atmospheres Sputtering Surface Ice Sublimation Outgassing from the Interior: Volcanic and Geyser Activity Overview of the Tenuous Atmospheres Mercury and Moon Io Europa, Ganymede, Callisto Enceladus Triton Pluto 345 Problems 345 Chapter 7 Global Atmospheric Motions Equations of Atmospheric Motions Total and Partial Derivates Equations Continuity Equation of State Navier-Stokes Equation Thermodynamic Energy Equation 358

8 Contents XIII 7.2 Momentum Equation: Balances Tangent-Plane Geometry /-Plane Approximation /J-Plane Approximation Geostrophic Balance Cyclostrophic Balance Gradient Wind Balance Hydrostatic Equilibrium and Geopotential Boussinesq and Anelastic Approximations Thermal-Winds Rapidly Rotating Planet Slowly Rotating Planet Intermediate Case of a Moderately Rotating Planet Meridional Circulation Hadley Circulation Condensation Flows Vorticity Vorticity and Circulation The Vorticity Equation Potential Vorticity Quasi-Geostrophic Potential Vorticity The Planetary Boundary Layer and Turbulent Motions Motions Close to the Surface The Ekman Layer Ekman Pumping The Surface Boundary Layer and Mixing Length Generalized Turbulence Kolmogorov Turbulence Two-Dimensional Planetary Turbulence Observed Large-Scale Motions in the Planets Rapidly Rotating Bodies with Surface: Earth and Mars Slowly Rotating Bodies with Surface: Venus and Titan Tenuous Atmospheres: Triton, Pluto, and Io Giant Planets The General Circulation of Planetary Atmospheres Types of Dynamical Models The Primitive Equation (PE) Model Shallow Water (SW) One and a Half Model ("lw) Quasi-Geostrophic (QG) Numerical Solutions Finite Differences Spectral Methods 407

9 xiv Contents Angular Momentum and Energy Budgets Angular Momentum Balance Energy Budget and Transformations The Circulation of the Atmospheres of the Giant and Icy Fluid Planets Deep Circulation Models Shallow Layer Models The Uranus and Neptune Case Lower Stratosphere Circulation Extrasolar Planets: Circulation in "Hot Jupiters" 419 Problems 421 Chapter 8 Atmospheric Dynamics-I: Waves Wave Characteristics Wave Properties The Linear Theory Acoustic Waves Gravity Waves Pure Gravity Waves Topographic Stationary Waves Inertio-Gravity Waves Gravity Wave Observations Rossby Waves Barotropic Rossby Wave Three-Dimensional Rossby Wave Observed Nonequatorial Rossby Waves in Planets Planetary-Scale Equatorial Waves Horizontal Structure Kelvin Wave (j=-1) Rossby-Gravity or Yanai Wave 0 = 0) Inertia-Gravity Waves and Equatorial Rossby (j>l) Vertical Structure Representative Planetary-Scale Equatorial Waves Thermal Tides: Dynamics QBO-QQO and SAO Oscillations 461 Problems 464 Chapter 9 Atmospheric Dynamics-II: Instability Scales of Motion and Dimensionless Numbers Vertical Instability: Convective Motions 473

10 9.2.1 Dry Convection Moist Convection Convective Phenomena in Planetary Atmospheres Venus Earth Mars Titan Giant Planets: General Jupiter Saturn Uranus and Neptune Lightning Hydrodynamic Instability: Vortices Natural Coordinates Trajectories and Streamlines Vorticity and Divergence Mean Vorticity and Divergence Balanced Flow Geostrophic Vortices Inertial Motion Cyclostrophic Vortices Gradient Wind Vortices Types of Hydrodynamic Instabilities Kelvin-Helmholtz Instability Inertial Instability Barotropic Instability Baroclinic Instability Fundamentals Eady Model Baroclinic Instability in Planets Vortices in the Giant Planets Data from Observations Models Other Dynamical Phenomena Mesoscale Vortices Dust Devils Earth's Tornado Von Kärmän Streets Martian Dust Storms Earth Equatorial-Tropical Phenomena The Intertropical Convergence Zone and Equatorial Disturbances Tropical Cyclones Belts and Zones and Planetary-Scale Disturbances in Jupiter and Saturn 525 XV

11 Contents The South Equatorial Belt Disturbance in Jupiter The North Temperate Belt Disturbance in Jupiter The South Tropical Zone Disturbance (STrD) in Jupiter Polar Dynamics Earth Polar Vortex Polar Dynamics in the Planets Mars Venus North and South Dipole Titan Polar Vortex Jupiter Poles Saturn Polar Vortices Uranus and Neptune Poles Atmospheric Effects of the Impact of Comet Shoemaker-Levy 9 with Jupiter Impact "Fireball" and "Blowout" Plume Flight Plume Splash and Aerosol Cloud Formation Cloud and Environment Evolution The July 19th 2009 Impact 541 Problems 543 Appendix: Methods to Study Planetary Atmospheres 553 A.l Remote Sensing Measurements 553 A.l.l Ground Telescopes and Radiotelescopes 554 A.1.2 The Atmospheric Window 555 A. 1.3 Remote Sensing Telescopes and Spacecrafts 555 A Earth Orbiting Space Telescopes 555 A.l.3.2 Planet Fly-by 558 A.l.3.3 Planet Orbiting 558 A.1.4 Remote Sensing Techniques 561 A Imaging 561 A Spectroscopy 564 A Remote Sounding from the Ground 565 A Occultation Techniques 566 A Gravitational Field Measurements 567 A.2 In Situ Atmospheric Measurements 567 A.2.1 Descending Probes 567 A.l.l Balloons 568 A.2.3 Landers and Rovers 568 A.3 Laboratory Studies and Numerical Modeling 569 A.3.1 Fluid Dynamic Laboratories 569 A.3.2 Chemistry 570

12 Contents xvii A.3.3 Aerosol Properties 570 A.3.4 Computer Simulations: Predictions 570 A.4 Future Observing Facilities 571 Bibliography 573 Index 577