Atmosphere - Structure and Composition

Atmospheric Composition

Variable Gases:  Water Vapor 0.1% to 5% (by volume)  Carbon Dioxide365 ppm (parts per million)  Other "Greenhouse" gases

Water Vapor Pressure (mb) - January

Since the 1950s, the concentration of carbon dioxide has 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 Decline Global Warming Is Melting Their Ice Pack Habitat By Blaine Harden Washington Post Staff Writer Thursday, 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%; that is one-half the mass of the atmosphere is below you.  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 mb level Sea Level Pressure millibars

Atmospheric pressure is routinely plotted on maps by the use 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.The New Republic; Nov, 2009 July 19, 2010, 12:45 pm The Passing of a Climate Warrior