Atmospheres

1 / 30

# a df ffff ff - PowerPoint PPT Presentation

Atmospheres. Take a weather class for details (870:021) But until then… Physical Principles Structure Characteristics Origin/Evolution. Hydrostatic Equilibrium P=change in pressure G=Constant M=planet mass z=height r =density. Ideal Gas Law  =Constant T=Temperature (K)

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'a df ffff ff' - Jeffrey

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Atmospheres
• Take a weather class for details (870:021)
• But until then…
• Physical Principles
• Structure
• Characteristics
• Origin/Evolution
Hydrostatic Equilibrium

P=change in pressure

G=Constant

M=planet mass

z=height

r=density

Ideal Gas Law

=Constant

T=Temperature (K)

m=mean molecular weight

Atmospheric Physics
Combine them to get Pressure Scale Height (H)

(height needed for pressure to drop e )

Assume isothermal atmosphere

(good temperature assumption…?)

What influences the Temperature?
• Sun
• Internal energy sources – re-radiated light
• Chemical reactions – change opacity
• Clouds/haze – change opacity, latent heat
• Volcanoes/Geysers
• Oxidation/Sedimentation
• Biogenic, Anthropogenic processes
• Temperature structures not all the same
Localized temperature influences
• Distance from Sun
• Albedo
• Angle of the Sun
• Rotation rate
• Non-blackbody aspects - emissivity
Solar heating – assuming sun over equator

T = Surface temperature

Fsun= Solar Constant

(1360 W/m2)

A = albedo

f = latitude

e = emissivity

s = constant

a = distance from Sun

Atmosphere Structures
• Troposphere
• Tropopause
• Stratosphere
• Statopause
• Mesosphere
• Mesopause
• Thermosphere
• Thermopause/Exobase
• Exosphere
Wimpy Atmospheres
• Mercury
• O, Na, He, K, H, Ca, Xe, Kr, CO2, H2O, Ar
• P=10-15 bar, T=100-700 K
• Moon
• H, He, Ar, Na, K
• P=10-15 bar, T=120-380 K
• Pluto –
• N2, CO, CH4, ethane
• P=6.5x10-6 – 2.4x10-5bar, T=53 K
• Triton –
• N2, CH4
• P=1.4x10-5bar, T=40 K
• Io – SO2, SO
• Enceladus – N, CO2, CH4
Atmospheric Motions
• Circulation Patterns
• Thermal Tidal Winds
• Condensation Winds
• Rotation (Coriolis effect)
Origin
• Where do atmospheres come from?
• Why are they different?
• Origins different (location)
• Gravity - escape
• Chemical reactions – Photodissociation/Recombination

CH4 + H2O ↔ CO + 3H2

2NH3↔ N2 + 3H2

H2S + 2H2O ↔ SO2 + 3H2

Etc.

• Plus Ar, Kr, Xe in solar amounts – NOT!
• Outgassing
Earth’s Atmospheric History
• Past was hotter
• Early Greenhouse effect (H2O, CO2, CH4, NH3)
• CO2 cycles through a system
• Weathering
• Carbonate minerals
• Volcanism
• Oxygen – life, dissociation of H2O
Mars Atmospheric History
• Thicker in the past (Noachian era)
• Atmosphere ~ 1 bar, T ~ 300 K
• Rich in CO2, H2O
• CO2 lost through
• Weathering