Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Light and Aerosols

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High What are Aerosols? Aerosols are small particles that can remain suspended in the atmosphere for days or weeks. Natural Sources desert dust forest fires sea spray volcanic eruptions Human-related Sources fossil fuel burning biomass burning dust resulting from land clearing

CCAG Educator Workshop – Fort Collins, Colorado – July 2004 S.O.A.R. High Human-Induced Aerosols: Aerosols are made when people burn coal, gasoline, and other fossil fuels. Humans also produce aerosols when they burn wood in their fireplaces or when forests or grasslands are burned. ( biomass burning ) What are Aerosols? Biomass burning (human induced) Volcanic Ash (naturally occurring) Saharan Dust off West Africa (naturally occurring) Definition: Aerosols are particles, liquid or solid, that are suspended in the air. They are NOT gases. Naturally Occurring Aerosols: Volcanic eruptions hurl tons of ash into the atmosphere and natural forest fires caused by lightning also produce many aerosols. Some other examples include sea salt spray, desert dust, and pollen from plants.

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Human-Related Sources Sulfates, Soot Biomass Burning Natural Sources Desert Dust Sea Salt Aerosols may have a warming or cooling effect depending on their optical properties and surface brightness – key measurements by CALIPSO. Aerosols Directly Influence Earth’s Energy Balance

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Satellite Aura measures Aerosols Aura orbits the Earth - (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Natural & Man-made Aerosols Dust from China (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Natural & Man-made Aerosols Circulation of Water Vapor Aerosols Circulation of Water Vapor Aerosols (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Natural & Man-made Aerosols Mt. Pinatubo Mt. Pinatubo (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Natural & Man-made Aerosols Circulation of Volcanic Ash Aerosols Circulation of Volcanic Ash Aerosols (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Mechanisms of Energy Transport

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High How Do Aerosols Affect Climate? Aerosols absorb and scatter the sun’s energyAerosols absorb and scatter the sun’s energy. (animation)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High How Do Aerosols Affect Climate? Atmospheric aerosols directly affect Earth’s energy balance by: absorbing and scattering solar radiation absorbing and emitting infrared radiation Atmospheric aerosols indirectly affect Earth’s energy balance by: acting as cloud condensation nuclei modifying the reflectance and lifetime of clouds

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Kinds of Scattering There are two kinds of scattering: Mie Scattering Rayleigh Scattering

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Mie Scattering is caused by particles or aerosols that are larger than the wavelengths of radiation. Water droplets and large particles scatter all wavelengths equally, making hazy skies and white clouds. Mie Mie Scattering

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Rayleigh Scattering Rayleigh Scattering happens when some particles are better at scattering a particular wavelength of light. Air molecules, like oxygen and nitrogen, are small in size and better at scattering shorter wavelengths of light (blue and violet). The selective scattering by air molecules is responsible for producing our blue skies on a clear sunny day.

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High When great amounts of particles are in the atmosphere, Rayleigh Scattering filters out almost all of the shorter wavelengths, leaving the red wavelengths. Rayleigh Scattering, Red Sunsets

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Rayleigh Scattering, Red Sunsets

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Aerosol Demonstration (with overhead projector)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Aerosol Demonstration (with overhead projector)

Earth System Science Teachers of the Deaf Workshop, August 2004 S.O.A.R. High Fun Webpages