Class Outline What is Radiation and Radiative Forcing? –How does radiation differ from convection...
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Class Outline • What is Radiation and Radiative Forcing? – How does radiation differ from convection and conduction? • How does radiation from the sun interact with the Earth? • How does radiation from the Earth interact with greenhouse gases? – What is absorption, reflection and transmittance? • How are greenhouse gas amounts changing? • How can we observe the radiation that leaves the earth from satellites? – What does this information tell us about the temperature of features on Earth?
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Transcript of Class Outline What is Radiation and Radiative Forcing? –How does radiation differ from convection...
Class Outline
• What is Radiation and Radiative Forcing?– How does radiation differ from convection and conduction?
• How does radiation from the sun interact with the Earth?• How does radiation from the Earth interact with
greenhouse gases?– What is absorption, reflection and transmittance?
• How are greenhouse gas amounts changing?• How can we observe the radiation that leaves the earth
from satellites?– What does this information tell us about the temperature of
features on Earth?
What is radiation?
DEMO TIME!
FAQ 1.1, Figure 1
Earth’s energy balance
Green-house effect
What wavelengths of light does the sun emit?
or
A quick description of the sun’s energy
RadioMicrowavesInfraredVisible UltravioletX RaysGamma Rays
Wavelengths of LightW
avel
engt
h In
crea
ses
Light: Color and Wavelength
Distance (nanometers: millionths of a millimeter)
Violet (400 nm)
Indigo (425 nm)
Blue (450 nm)
Green (525 nm)
Yellow (575 nm)
Orange (615 nm)
Red (700 nm)
Light emitted by the Sun
http://feps.as.arizona.edu/outreach/bbplot.html
Wavelength of Peak emission = 2898 microns / Temperature of Blackbody (Kelvin).
Sun and Earth Energy Emission
http://ceos.cnes.fr:8100/cdrom-00b/ceos1/science/dg/dg9.htm
What kind of light does the sun emit?
DEMO TIME!
What is radiative forcing?
• Radiative forcing is a measure of the influence that a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system.
• Radiative forcing is an index of the importance of the factor as a potential climate change mechanism.
FAQ 1.1, Figure 1
Earth’s energy balance
Green-house effect
Earth’s Energy Balance
• Over the long term, the amount of incoming solar radiation absorbed by the Earth and atmosphere is balanced by the Earth and atmosphere releasing the same amount of outgoing longwave radiation.
• About half of the incoming solar radiation is absorbed by the Earth’s surface. – This energy is transferred to the atmosphere by
• warming the air in contact with the surface (thermals), • evapotranspiration • longwave radiation that is absorbed by clouds and greenhouse
gases.
– The atmosphere in turn radiates longwave energy back to Earth as well as out to space.
Greenhouse Gases
Global Carbon DioxideN
AS
A
Changes in Greenhouse Gases
The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change.
Changes in Greenhouse Gases
The increases of methane and nitrous oxide are primarily due to agriculture.
Reflection, transmittance and absorption
Absorption
DEMO TIME!
• Global Warming Art
• http://www.globalwarmingart.com/wiki/Image:Atmospheric_Transmission_png
Why different bands for water?
• The water vapor absorption bands are related to molecular vibrations involving different combinations of the water molecule’s three fundamental vibrational transitions:– symmetric stretch mode – bending mode – asymmetric stretch mode
Water Vapor Molecule Animation
• http://en.wikipedia.org/wiki/Water_absorption
How do we observe Earth’s radiation that goes to space?
Satellites
• Monitor one area constantly, as it remains stationary with respect to an observer on earth’s surface
Scan from north to south
Visible Light
Infrared Light
What will we study using satellite imagery of clouds and water
vapor?
•Thickness of clouds•Height of Clouds•Amounts of Water Vapor•In the next couple weeks we will discuss overall climate effects of clouds
How is our atmosphere structured?
Atmospheric Vertical Structure
Photo Credit: Bob Rohli
What do clouds look like from Earth above and below?
Name that Cloud!
STRATOCUMULUSStable layers in the atmosphere slow vertical
development. Rounded masses larger than altocumulus. Often appear near sunset as the spreading remains of larger cumulus clouds.
Name that Cloud!
STRATUSA uniform grayish cloud that often covers the entire sky. Resembles fog that does not reach
the ground. Layer of air cooled to the saturation point. Featureless with ill defined
top and bottom.
Name that Cloud!
ALTOCUMULUSForms in unstable layer bounded by an upper
stable layer. Possible marker of PM t-storms when seen in the AM with greater vertical
development. Gray, puffy masses.
Name that Cloud!
NIMBOSTRATUSA clouds producing continuous precipitation (light to moderate). Thick mass of cloud with
no well defined base, dark gray in color, usually covering most of the sky.
Name that Cloud!
CUMULONIMBUSOr “thunderstorm” cloud. Most energetic of cumulus family. Top can shoot up into lower stratosphere. Anvil cloud is forming. Heavy downpours, lightning, and hail can result.
Name that Cloud!
CIRROCUMULUSSmall ripples strongly resemble the scales of a
fish. Usually occur in patches and do not cover entire sky. Heaps smaller than
altocumulus.
Common Cloud Types
Click here for:
Satellite loop of the United States
Are the clouds moving in your direction?
When will they reach you?
Earth Surface
Infrared Energy
Infrared Energy
High CloudHigh Cloud
Low CloudLow Cloud
Cold
Satellite
Infrared Image
Warm
Appears Gray Appears White
High and Low Clouds in Infrared Image
Visible image Infrared image
Click here for:
Infrared Satellite loop of the United States
Are the clouds moving in your direction?
When will they reach you?
