1. Atmospheric Radiation
ESE_GE 152 April 7, 2009
Yuk Yung
Chapter 1 1

2. Outline Blackbody Energy Balance (1) Energy Balance (2)
Thermal Structure
Composition 2

3. Blackbody Radiation
B(T) = 2h3/c2[exp(h/kT) - 1]-1 3

5. 5

10. Brightness Temperature

12. Outline Blackbody Energy Balance (1) Energy Balance (2)
Thermal Structure
Composition 12

13. Atmosphere : Processor of energy
Sun
surface
Atmosphere
Space
Center of sun
Atmosphere : Processor of energy
Sunlight driver of
Chemistry dynamics biology

14. Process
Total Power (Watts)
Sunlight
2 X 1017
Seawater evaporation
3 X 1016
Photosynthesis
1 X 1014
Geothermal flux
3 X 1013
Tides
2 X 1013
Energy use by man (1980)
1 X 1013
UV energy to make O3 layer
Hydroelectric Power
3 X 1011
Winds
2 X 1011
Volcanoes
4 X 1010
Earthquakes
1 X 1010

16. “One layer” Greenhouse Model of Atmosphere
Atmosphere is blackbody (thermal)
Atmosphere is transparent to solar radiation
Atmosphere is “one layer” thick and isothermal throughout
Radiative equilibrium for planet
Radiative equilibrium for surface
Solving
observed
Pretty good (Ts = 288 K)

17. Outline Blackbody Energy Balance (1) Energy Balance (2)
Thermal Structure
Composition 17

18. George Hadley (1685-1768), English lawyer and scientist.
“I think the cause of the general Trade-winds have not been explained by any of those who have wrote on that subject” (1735)
The overturning Hadley cells are the main way the atmosphere transports energy polewards in low latitudes

20. Radiation TOA
Quite strong structure due to clouds in ASR and OLR that mostly cancels in the net; some other albedo effects (e.g., Sahara) and land-sea differences, but sun-Earth geometry explains most of pattern.
ASR
OLR
NET
Trenberth and Stepaniak, J. Clim. 2003

23. Net Differences Kiehl and Trenberth 1997 Shortwave Surface
Top-of-atmosphere
Top-of-atmosphere
Surface
Net Differences
Shortwave
Kiehl and Trenberth 1997

24. Radiation TOA
Quite strong structure due to clouds in ASR and OLR that mostly cancels in the net; some other albedo effects (e.g., Sahara) and land-sea differences, but sun-Earth geometry explains most of pattern.
ASR
OLR
NET
Trenberth and Stepaniak, J. Clim. 2003

25. Outline Blackbody Energy Balance (1) Energy Balance (2)
Thermal Structure
Composition 25

30. Outline Blackbody Energy Balance (1) Energy Balance (2)
Thermal Structure
Composition 30

34. x: Machida et al. [1995] +: Bernard et al. [2006]
Sowers’s 10 ppbv lower in PRE

37. Elva Kuai, Fai Li, Trenberth, Barnet Goody + Yung Book
Thanks
Elva Kuai,
Fai Li,
Trenberth, Barnet
Goody + Yung Book