1. The Sun Sun is middle aged (4.5 ba / 11 ba)
Sun is one of 1011 stars in Milky Way galaxy
Sun is big - compare the size of a coronal flare (eruptive prominence) and the size of Earth
Radiation produced by fusion of H (75%) to He (24%)

2. Variability in Solar Radiation
Faint Young Sun paradox
2. 11-year sunspot cyclicity

3. Weather vs. Climate
Statistical distribution (climate) of stochastic events (weather)

4. Water on the Earth’s surface
Earth is the “water planet” because H2O can exist in all 3 phases on the surface.
Recall water phase diagram.
Earth is just the right distance from the sun, to keep water in all three phases.
Mean temp. of Earth surface ~= 15oC

5. Radiation Balance
Want to understand the temperature of the Earth’s surface.
What is the control volume of interest here?
Perform an Energy Flux balance.
… and employ the Stefan-Boltzman Law.

6. Discrepancy: Earth’s predicted vs. observed surface temperature

7. Blackbody Radiation and Absorption of Certain Energy Wavelengths
Atmospheric gasses absorb certain wavelengths of the incoming and outgoing radiation spectra
Radiation in the visible (~0.5 micron wavelength) - relatively unaltered
The infrared band (~10 micron wavelength) – significant absorbtivity
Wein's Law predicts outgoing radiation peaks in infrared band - greenhouse gasses trap outgoing radiation – drives up surface temperatures by about 33K (from -18oC to +15oC)

8. Distribution of Radiation (Insolation)
Snow/Ice-covered poles have very high albedos relative to the oceanic low latitudes.

9. Poleward Energy Transport
Net radiation distribution
Continental landmass distribution
Oceans and atmosphere (the climate system) transport energy poleward by advection (fluid in motion).

10. Latitudinal Distribution of Energy Transport
The integral of the net radiation balance is the heat transport curve.

11. Vertical Structure of the Atmosphere
Derive pressure and density structure from ideal gas law approximation

12. Atmospheric Circulation – Hadley Cells

13. Atmospheric Circulation – Hurricanes