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Climates of Terrestrial Planets

Climates of Terrestrial Planets. Dave Brain LASP / CU Boulder. An interesting question with no definite answer will be posed here, for you to look at until the lecture actually starts. Do magnetic fields affect planet surfaces?. Do magnetic fields affect atmospheres?.

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Climates of Terrestrial Planets

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  1. Climates of Terrestrial Planets Dave Brain LASP / CU Boulder An interesting question with no definite answer will be posed here, for you to look at until the lecture actually starts Do magnetic fields affect planet surfaces? Do magnetic fields affect atmospheres? Do magnetic fields affect climate?

  2. Approach • Climates Heliophysics • Climates • Changing Climates • Atmospheric Escape Processes • [ Break ] • Heliophysics Climates • External Drivers • Internal Drivers • Prospects

  3. I. Climates

  4. Contemporary Climates

  5. II. Changing Climates

  6. A very exciting question will be asked here

  7. Four Ways to Change TSurface Solar Output Planetary Albedo NASA Ames / J. Laskar Ribas et al., 2010 Greenhouse Gas Content Planetary Orbital Elements

  8. Evidence for Climate Change Venus Matsui et al., 2012 Strom et al., 1994

  9. Evidence for Climate Change Mars Geomorphology Geochemistry Isotopes Jakosky and Phillips, 2002

  10. Evidence for Climate Change Earth • Ice • Bubbles  composition • Isotopes  temperatures • Pollen  conditions • Trees and Coral • Separation  growth rate  climate • Sediment • Fossils / pollen  conditions • Composition  temperature • Layering  climate shifts • Texture  environment

  11. Atmospheric Source and Loss Processes Source Outgassing Source and Loss Impacts Surface exchange Loss Escape to space Hydrodynamic escape

  12. III. Atmospheric Escape Processes

  13. Wow – another question!

  14. Requirements for Escape • Escape Energy • Directed Upward • No Collisions • Escape from exobase region

  15. Reservoirs for Escape Lots of red here (I got tired) Space Surface Thermosphere T(z)  Diffusive equilibrium V: ~120-250 km CO2, CO, O, N2 E: ~85-500 km O2, He, N2 M: ~80-200 km CO2, N2, CO Ionosphere Small % of neutrals Incident energy forms peaks V: ~120-300 km O2+, O+, H+ E: ~75-1000 km NO+, O+, H+ M: ~80-200 km O2+, O+, H+ Exosphere “collisionless” Ballistic trajectories V: ~250-8,000 km H E: ~500-10,000 km H, (He, CO2, O) M: ~200-30,000 km H, (O)

  16. Terrestrial Planet Magnetospheres Intrinsic Magnetosphere Induced Magnetosphere Cartoons courtesy S. Bartlett

  17. Escape Processes

  18. Neutral Particle Processes Jeans Escape (E,M) Photochemical Escape (V,M) O2+ + e- O* + O* Sputtering (V, M)

  19. Charged Particle Processes Ion pickup (V,M) Ion outflow (V,E,M) Luhmann and Kozyra, 1991 Moore et al., 1999 Bulk plasma escape (V,M)

  20. Alternative Classification Scheme Pickup Hall Electron Pressure Gradient • Electric fields accelerate charged particles • Can loosely identify pickup, Hall, and pressure gradient escape • Highlights that combinations of mechanisms can accelerate ions

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