Don't Let This Happen to Your Planet   
       
   March 29, 2013: Ozone stinks.  People who breathe it gag as their lungs burn.    
   The EPA classifies ground-level ozone as air pollution.   
       
   Yet without it, life on Earth would be impossible.   
       
   A fragile layer of ozone 25 km above Earth's surface is all that stands   
   between us and some of the harshest UV rays from the sun. The ozone molecule   
   O3 blocks radiation which would otherwise burn skin and cause cancer.  On   
   Mars, which has no ozone layer to protect it, solar UV rays strafe the surface   
   with deadly effect, leaving the apparently lifeless planet without the   
   simplest of organic molecules in the upper millimeters of exposed Martian soil.   
       
   To keep track of our planet's ozone layer, NASA is about to launch the most   
   sophisticated space-based ozone sensor ever: SAGE III, slated for installation   
   on the International Space Station in 2014.   
       
   http://www.youtube.com/watch?v=DEdqeHHoYKU   
       
   A new ScienceCast video explains how SAGE III onboard the International Space   
   Station will monitor the recovery of Earth's fragile ozone layer. Play it"The   
   ISS is in the perfect orbit for SAGE III," says Joe Zawodny, Project Scientist   
   for the instrument at the Langley Research Center.  "It will be able to   
   monitor ozone all around the Earth during all seasons of the year."   
       
   SAGE III works by using the Sun and Moon as light sources.  When either one   
   rises or sets behind the edge of the Earth, SAGE III analyzes the light that   
   passes through Earth's atmosphere.  Ozone and other molecules absorb specific   
   wavelengths that reveal their density, temperature and location.   
       
   "SAGE III is, essentially, analyzing the colors of the sunset to track ozone,"   
   says Zawodny. "It sounds romantic, but this is hard science."   
       
   Researchers began to worry about ozone in the early 1970s when University of   
   California chemists Frank "Sherry" Rowland and Mario Molina testified before   
   Congress that manmade CFCs, a key ingredient of common aerosol sprays, could   
   destroy ozone in the stratosphere.  Their fears were soon realized. In 1985,   
   researchers with the British Antarctic Survey announced abnormally low ozone   
   concentrations above Halley Bay near the South Pole.  Our planet had an "ozone   
   hole," and it was rapidly growing.   
       
   http://www.nasa.gov/images/content/522308main_ISS013-E-54329-800.jpg   
       
   Moonlight beaming through the edge of Earth's atmosphere reveals the ozone   
   content to SAGE III. MoreIn a remarkable display of international cooperation,   
   an ozone treaty was negotiated only two years later. The Montreal Protocol   
   regulates the production of CFCs and other ozone-destroying chemicals.  First   
   signed in September 1987, it has since been ratified by every member of the   
   United Nations.   
       
   Because of this agreement, ozone is now on the mend.  Ozone holes still open   
   every year above the South Pole, but thanks to the treaty, ozone-destroying   
   chemicals have either leveled off or decreased. At this rate, the ozone layer   
   could recover almost fully by 2050.   
       
   To insure that ozone really is recovering--and to alert the world if it is   
   not--NASA has been flying ozone sensors in Earth orbit for decades.   
       
   The first of the SAGE sensors rode to space on Earth observing satellites in   
   the late-1970s and early-80s.  SAGE II data helped confirm the decline of the   
   ozone layer and measured the effect of the Mt. Pinatubo eruption on the   
   stratosphere. A SAGE III sensor onboard the Russian Meteor-3M satellite   
   extended the ozone record into the 2000s with higher precision than ever.   
       
   It is not unusual for researchers to refer to SAGE as "the gold standard" in   
   ozone monitoring. "The SAGE ozone product has a high accuracy, better than 1%   
   in the mid-to-lower stratosphere, and a very high vertical resolution of 1km   
   or better," says Zawodny.   
       
   When SAGE III reaches the space station, it will measure ozone deeper into the   
   atmosphere than ever before, reaching all the way down into the troposphere   
   where planes fly and people live.   
       
   http://science.nasa.gov/media/medialibrary/2013/03/29/sage3_med.jpg   
       
   Preparing for launch: SAGE III in the laboratory at Langley Research Center.   
   More"From ISS, SAGE III will get a global picture of tropospheric ozone," says   
   Zawodny. "I suspect there will be a few surprises in those measurements."   
       
   Zawodny is eager to learn what SAGE III finds in the lower stratosphere over   
   the tropics. "The recovery of ozone there is tied to changes in greenhouse   
   gases like CO2. Given what we know about recent increases in greenhouse   
   emissions, it is possible that ozone in the tropics will never return to 1980s   
   levels."   
       
   SAGE III probes Arctic regions, too.  Using the Moon as a light source, SAGE   
   III can to detect ozone during the darkness of polar winter where other   
   satellites have trouble seeing.   
       
   It's enough to make a hard-nosed researcher wax eloquent: "Images of the moon   
   and sun rising and setting are dramatic and spectacular," says Zawodny. "The   
   interplay between the source of light and the environment delights the senses   
   and stirs the imagination. The ability for SAGE III to turn those perceptions   
   into something meaningful is a great pleasure."   
       
   In other words, stay tuned for some beautiful ozone data.   
       
   Credits:   
       
   Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
   More information:   
       
   Stratospheric Aerosol and Gas Experiment -- SAGE home page   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.91   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)