atmosphere - structure and composition. atmospheric composition
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Atmosphere - Structure and Composition
Atmospheric Composition
Variable Gases:
Water Vapor 0.1% to 5% (by volume)
Carbon Dioxide 365 ppm Other "Greenhouse" gases
Water Vapor Pressure (mb) - January
Since the 1950s, the concentration of carbon dioxidehas increased at a rate of about 1.8 ppm per year.
The increase has occurred mainly because of anthropogenic combustion and deforestation
of large tracts of woodland.
Carbon dioxide increase since the 1950s
Experts Predict Polar Bear DeclineGlobal Warming Is Melting Their Ice Pack HabitatBy Blaine HardenWashington Post Staff WriterThursday, July 7, 2005
The photograph taken in 1928, above, shows how the Upsala Glacier, part of the South American Andes in Argentina, used to look. The ice on
the Upsala Glacier today, shown in 2004 below, is retreating at least 180 ft. per year
Time Magazine – March 26, 2006
Particulates (Aerosols)
Aerosols - particulates
.....increasing?….decreasng?
Atmospheric Aerosol Properties and Climate Impacts
U.S. Climate Change Science Program
Synthesis and Assessment Product 2.3
January 2009
Vertical Structure is Crucial
The world is a big place, but the atmosphere is very thin, and most of it is close to the ground The atmosphere is most dense near the
surface At the top of Mount Denali (18,000 feet
above sea level), the figure is 50%
Changes in atmospheric temperature and composition with height above the surface account for our weather and account for the “greenhouse effect”
Vertical Structure of the Atmosphere
Atmospheric Pressure (millibars)
18,000 feet --- 500 mb level
Sea Level Pressure --- 1013 millibars
Atmospheric pressure is routinely plotted on maps by theuse of lines called isobars. Each isobar connects points
having equal air pressure with the pressure being expressed in units of millibars (mb) in the United States
and kilopascals (kPa) in Canada.
A surface weather map
Surface Maps
500-mb Level Maps
Vertical Thermal Structure
Heated from below by latent and sensible heat fluxes
Heated in stratosphere by ozone absorption
Interview
Q&A: Dr. Stephen Schneider, one of the world's leading climatologists, discusses the line between science and activism. The New Republic; Nov, 2009.
July 19, 2010, 12:45 pm The Passing of a Climate Warrior