planetary atmospheres greenhouse effect greenhouse effect 90 atmospheres!

Download Planetary Atmospheres Greenhouse Effect Greenhouse Effect 90 atmospheres!

Post on 02-Jan-2016

216 views

Category:

Documents

2 download

Embed Size (px)

TRANSCRIPT

  • Planetary Atmospheres Greenhouse Effect

    90 atmospheres!

  • Planetary Atmospheres Greenhouse Effect

    CO2 H20

    240 watts/m2in

    240 watts/m2out

    50% reflected byclouds and surface

    Small fractionescapes intospace

  • Planetary Atmospheres Greenhouse Effect

    Energy InEnergy Out100 energy units100 energy units100% gate50% gate200 energy unitsstoredin equilibrium

  • Planetary Atmospheres Greenhouse Effect

    Energy InEnergy Out100 energy units100 energy units100% gate1% gate10, 000 energy unitsstoredin equilibrium

  • Planetary Atmospheres Greenhouse Effect

  • Frosts are most likely to happen on clear nights rather than cloudy nights. This is because

    A) Cloudy nights lead to falling snow B) Clouds are not transparent to optical light C) More infrared light can be radiated through clear skies D) Snow and frost reflect rather than absorb visible light

    ConcepTest!

  • Planetary Evolution Essential Idea

    Evolution of both geology and atmospheres driven by energy flow from planetary cores

  • Planetary Evolution Essential Idea

    Recall Amount of residual thermal energy stored in planet depends on planet volume (amount of material)

    Rate of energy loss depends on planet surface area

    Small planets go dormant sooner

  • Planetary Evolution Comparative Planetology - Earth and Mars

    Mars Earth

    Dormant volcanos Active volcanos

  • Planetary Evolution Comparative Planetology - Earth and Mars

    Mars Earth

    Dormant volcanos Active volcanosWater in past Water at present

  • Planetary Evolution Comparative Planetology - Earth and Mars

    Mars Earth

    Dormant volcanos Active volcanosWater in past Water at presentThin CO2 atmosphere N2/O2 atmosphere (0.01 atmos) (1 atmos)

    Note: Liquid water would not survive on Mars today - it would boil due to low atmospheric pressure. So if liquid water in past, must also have been substantial atmosphere and greenhouse effect in past Active volcanoes could have provided such an atmosphere

  • Planetary Evolution Comparative Planetology - Earth

    washed out with H20 rainOzone O3

  • Planetary Evolution Comparative Planetology - Earth

    Life is critical to oxygen in Earth atmospherewashed out with H20 rainOzone O3

  • If plate tectonics on the Earth were to end, you would expect the temperature of the Earths surface to

    A) Increase B) Change little or not at all C) Decrease

    ConcepTest!

  • Planetary Evolution Comparative Planetology - Mars at 1 billion yr (end of geologic activity)

    H2O rain washes CO2 into surface - permanently Greenhouse effect reducedColder temperatures lead to enhanced rain, less gaseous CO2, less greenhouse (Runaway Icehouse Effect)Most CO2 in carbonate rocks, most H2O in permafrostUV sunlight breaks up molecules and provides energy of escapeUVO,C

  • Planetary Evolution Comparative Planetology - Mars at 4.5 billion yr

    Recent liquid water?

  • Planetary Evolution Comparative Planetology - Earth and Venus

    Venus Earth

    Active volcanos Active volcanos

  • Planetary Evolution Comparative Planetology - Earth and Venus

    Venus Earth

    Active volcanos Active volcanosVesc = 10.3 km/sec Vesc = 11.2 km/sec

  • Planetary Evolution Comparative Planetology - Earth and Venus

    Venus Earth

    Active volcanos Active volcanosVesc = 10.3 km/sec Vesc = 11.2 km/secCO2 atmosphere N2/O2 atmosphere (90 atmos) (1 atmos)

  • Planetary Evolution Comparative Planetology - Earth and Venus

    Venus Earth

    Active volcanos Active volcanosVesc = 10.3 km/sec Vesc = 11.2 km/secCO2 atmosphere N2/O2 atmosphere (90 atmos) (1 atmos)Dry (10-4 Earth H20) Water at present

    Note: Based on measurements of deuterium (heavy water) Venus had substantially more water in the past Consistent with outgassing from volcanos and large escape velocity

  • Planetary Atmospheres Comparative Planetology - Venus Suppose Venus were Earth-like (liquid water) and

    Runaway Greenhouse Effect

  • Planetary Atmospheres Runaway Greenhouse Effect

    once RGE begins

    RGEH20 inatmosUVfromSunH2O2EscapeSurfaceCompounds+Irreversible!!

  • Planetary Atmospheres Comparative Planetology - Venus at 4.5 billion yr

  • Planetary Evolution - SummaryMercury

    Trace ofHe, Na, OVenus

    96% CO2470 oC90 atmospheresEarth

    77% N2, 21% O215 oC1 atmosphereMoon Trace of He, Na, Ar

    Mars

    95% CO2-50 oC0.01 atmospheres

  • Planetary Evolution - Summary Geological Evolution Mercury, Moon - smallest radii => dormant, cratered Mars - active for 109 yr, now dormant (shield volcanoes) Venus - current volcanos (shield volcanoes) Earth - convection => plate tectonics

    Lost this before lecture, so reinserted after lecture.Lost this before lecture, so reinserted after lecture.This went very well.This went very well.