1. The Physical Basis of Climate (ATSC5400/4400) Spring 2011 Stellarsphere Slides Sun and Plancks Function Orbital influences on climate (Croll – Milankovitch)Orbital influences on climate (Croll – Milankovitch)

3. Solar Radiation Sun - typical main sequence dwarf star R o = 6.95 x 10 5 km, M o = 2 x 1030 kg 71% H, 26.5% He, 2.5% heavier metals Mean earth sun distance 1.496 x 10 8 km Core out to 0.25 R o Temperature ~ 10 7 K  Hot enough to cause fusion of H in to He  provides energy for the sun. Energy transfer by radiation, temperature ~ 10 6 K, ~0.7 R o Final ~0.3 R o energy transfer by convection  violent small scale (10 3 km) mixing process  granulation Photosphere ~ 1000 km thick, dominant source of solar radiation - relatively continuous emission - determines sun's blackbody temperature, 5800 K. Sunspots here. Chromosphere - 5000 - 10,000 km thick, temperature ~ 10 5 - 10 6 K. Radiation from emission lines from H, He, Ca. Corona - region above chromosphere, extending out for several solar diameters, temperature ~ 10 6 K. Prominences, Solar flares appear here. Origin of solar wind. Most solar energy in the continuum is from non- quantized electronic transitions (free - free, bound - free transitions)

4. B(υ,T)=2hυ 3 /c 2 [1/(e hυ/(kT) -1)] B(λ,T) = -8πhc/λ 5 1/[e hc/(λkT) -1]

5. B(υ,T)=2hυ 3 /c 2 [1/(e hυ/(kT) -1)]

6. B(λ,T) = -8πhc/λ 5 1/[e hc/(λkT) -1] B(υ,T)=2hυ 3 /c 2 [1/(e hυ/(kT) -1)]

8. http://www.pmodwrc.ch/tsi/composite/pics/org_comp2_d41_62_1009.png http://blog.ltc.arizona.edu/azmasternaturalist/Sunspot%20cycle.JPG

9. http://solarscience.msfc.nasa.gov/images/ssn_predict_l.gif

12. http://www.universetoday.com/wp-content/uploads/2008/10/moon_formation.jpg

15. Precession of 90° implies planet closest to sun in fall

17. Figure 7.2 Map of July-January surface air temperature differencesFig. 7.2 Map of July-January surface air temperature difference (C).

18. Milankovich cycles: Eccentricity-100,000 Obliquity-41,000 Precession-23,000 years 41,000 y 100,000 y 23,000 y CO2 today

20. http://upload.wikimedia.org/wikipedia/commons/5/53/MilankovitchCyclesOrbitandCores.png Obliquity Eccentricity Precession Ecc * Prec Solar insolation  ------- Pleistocene ---------------------Holocene Croll -

21. Harvey, 2000 Houghton, 2004