Solar Luminosity- How Bright the star Twinkles

1
Solar Luminosity- How Bright the star Twinkles

• Hotter temperature more light flux
• Increases in Luminosity seems to be linked to
  sunspot activity (sunspots are a little dimmer?
  counter intuitive, but brighter spots make up for
  dimmer spots)
• Sunspot activity cycles every 11 years or so

http//www.globalwarmingart.com/wiki/FileSunspot_
Numbers_png
2
Black Body Radiation
5000
3000
2000
1000
500
300
3
http//www.pmodwrc.ch/pmod.php?topictsi/composite
/SolarConstant
4
Flux from a black body
S kT4 , k5.67x10-8 watts/m2K4 (Wiens law)
6000 K
279 K
1370 Watts/m2
Sun
1.5x1011 m
EARTH
342 Watts/m2
6378 km r
5
?max (nm) 2.9x106/T
278
6
Tavg. 288 K !!
http//www.ipcc.ch/
7
http//www.ipcc.ch/
8
http//www.ipcc.ch/
9
World Carbon Dioxide Emissions
http//en.wikipedia.org/wiki/FileGlobal_Carbon_Em
issions.svg
10
http//en.wikipedia.org/wiki/FileMauna_Loa_Carbon
_Dioxide-en.svg
11
http//www.ipcc.ch/
12
The Role of Water Vapor and Clouds on Climate
Water Vapor The main heat-trapping gas in the
lower atmosphere Clouds Formed when water vapor
in the air condenses Clouds cool Earth by
reflecting incident sunlight into space Clouds
warm Earth by absorbing the heat released from
the ground and reradiating this heat back down
to the planet
The mean distribution of total atmospheric water
vapor above the Earths surface (1992).
http//okfirst.ocs.ou.edu/train/meteorology/Energy
Budget2.html
http//www.agu.org/sci_soc/mockler.html
13
Albedo Effect

• reflectance of incident sunlight by clouds, ice,
  snow, and light colored surfaces
• strongly correlated to the color of the surface
• feedback effects

31 of light reflected Back into space
Ice/Snow
14
Methane Sources and Sinks

• Sources (Mt/year)
• Wetlands 150
• Oceans, lakes 35
• Cattle 120
• Rice Paddies 95
• Other Sources150
• Natural Gas Leaks???
• Sinks
• CH4 OH ----gt CH3 H2O
• Sources gt Sinks resulting in about a 1-2 annual
  increase

Wetlands
Other Sources
Oceans, lakes

Rice Paddies
Cattle
15
http//www.ipcc.ch/
16
(No Transcript)
17
http//www.ipcc.ch/ http//www.epa.gov/nitro
usoxide/sources.html
18
http//www.ipcc.ch/
19
Gas GWP Carbon dioxide (CO2) 1 Methane
(CH4) 21 Nitrous oxide (N2O) 310 Hydrofluorocarbo
n 11,700 HFC-32 650 HFC-41 150 HFC-43-10mee
1,300 HFC-125 2,800 HFC-134 1,000 HFC-134a 1
,300 HFC-143 300 HFC-143a 3,800 HFC-152a 140
20
Global Circulation

• Warm air olds more moisure than cold air, and
  moist air retains heat longer than dry air.
• The sun warms air at the equator, as the air gets
  warmer it rises, spreads out, and cools
  (adiabatic cooling)
• This cooled air then goes poleward and drops at
  30
• Air warms as it drops, so it picks up moisture,
  deserts occur at 30
• Equatorial air is replaced by winds coming in
  from the 30s (tradewinds)
• Wind moves poleward along the earths surface
  between 30 and 60
• Coriolis Force causes the westerlies
• Water has a higher specific heat than air
• Air coming off the water in Northern
  areas(California,
• England) will be warmer than the land, so as it
  goes over the land and cools it drops moisture.
• During the summer, the land may be warmer than
  the water, so the air picks up moisture as it
  moves over the land creating wet winters and
  dry summers.

21
Overall patterns
22
1) Historical and predicted integrated CO2
production and resultant atmospheric CO2
concentration assuming no interaction with the
ocean.
23
CO2 SOLUBILITY IN THE WORLDS OCEANS
Molecular Weight (g/mol)
Diffusion Coefficient (x10-5 cm2/sec)
0C 24C
SxD (gas) SxD (O2)
Gas
He Ne N2 O2 Ar Kr Xe Rn CO2 N2O
4 20 28 32 40 84 131 222 44 44
4.0 2.8 2.1 2.3 1.5 1.4 1.4 1.4 1.9 2.0
0.54 0.44 0.45 1.00 0.72 1.2 2.5 4.8 23 18
2.0 1.4 1.1 1.2 0.8 0.7 0.7 0.7 1.0 1.0
Molecular diffusion rates of various gases in
seawater (35 salinity)
Broecker, W.S., Peng, T.-H. Tracers in the Sea.
New York Eldigio Press, 1982.
24
http//www.ssec.wisc.edu/data/sst/latest_sst.gif
http//oceanworld.tamu.edu/resources/ocng_textbook
/chapter13/chapter13_03.htm
25
Ocean circulation model
http//svs.gsfc.nasa.gov/vis/a010000/a010000/a0100
31/index.html

• mixing time is 1000 years!

26
Predicted atmospheric CO2 concentrations for four
different ocean mixing scenarios. The current
atmospheric CO2 concentration is marked with an
X.
27
http//www.ipcc.ch/
28
http//www.ipcc.ch/
29
FAQ 8.1, Figure 1
30
Figure 10.1
31
Figure 11.11
32
Figure 11.12
33
Figure 11.13
34
FAQ 9.2, Figure 1
35
Figure 10.4
36
http//www.ipcc.ch/
37
http//www.ipcc.ch/
38
Figure 10.12
39
Climate Engineering

• Change radiative flux
• Increase outgoing solar radiation via CO2
  reduction
• Decrease absorbed solar radiation
• Albedo aerosols, space-based technology
• Carbon capture
• Forests, oceans

Sources Matthews, B. 1996. A critical review
of proposals, their scientific and political
context, and possible impacts. Scienctists for
Global Responsibilty. http//www.chooseclimate.o
rg Keith, D.W. 2000. Geoengineering the
climate History and prospect. Annual review of
energy and the environment 25245-284
40
(No Transcript)