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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?
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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?
What is radiation? DEMO TIME!
Earth’s energy balance FAQ 1.1, Figure 1 Green-house effect
What wavelengths of light does the sun emit? or A quick description of the sun’s energy
Wavelengths of Light Radio Microwaves Infrared Visible Ultraviolet X Rays Gamma Rays Wavelength Increases
Light emitted by the Sun Wavelength of Peak emission = 2898 microns / Temperature of Blackbody (Kelvin). http://feps.as.arizona.edu/outreach/bbplot.html
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.
Earth’s energy balance FAQ 1.1, Figure 1 Green-house effect
Earth’s Energy Balance • Over the long term, the amount of incoming solar radiationabsorbed 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.
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.
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
Satellites Monitor one area constantly, as it remains stationary with respect to an observer on earth’s surface Scan from north to south
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
Atmospheric Vertical Structure Photo Credit: Bob Rohli
Name that Cloud! STRATOCUMULUS Stable 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! STRATUS A 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! ALTOCUMULUS Forms 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! NIMBOSTRATUS A 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! CUMULONIMBUS Or “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! CIRROCUMULUS Small ripples strongly resemble the scales of a fish. Usually occur in patches and do not cover entire sky. Heaps smaller than altocumulus.
Click here for: Satellite loop of the United States Are the clouds moving in your direction? When will they reach you?
High and Low Clouds in Infrared Image Infrared Image Appears Gray Satellite Appears White Infrared Energy Infrared Energy High Cloud Cold Warm Low Cloud Earth Surface
Click here for: Infrared Satellite loop of the United States Are the clouds moving in your direction? When will they reach you?