Tech

October 26, 2012

2012 Antarctic ozone hole second smallest in 20 years

The average area covered by the Antarctic ozone hole this year was the second smallest in the last 20 years, according to data from NASA and National Oceanic and Atmospheric Administration satellites.

Scientists attribute the change to warmer temperatures in the Antarctic lower stratosphere.

The ozone hole reached its maximum size Sept. 22, covering 8.2 million square miles (21.2 million square kilometers), or the area of the United States, Canada and Mexico combined. The average size of the 2012 ozone hole was 6.9 million square miles (17.9 million square kilometers). The Sept. 6, 2000 ozone hole was the largest on record at 11.5 million square miles (29.9 million square kilometers).

“The ozone hole mainly is caused by chlorine from human-produced chemicals, and these chlorine levels are still sizable in the Antarctic stratosphere,” said NASA atmospheric scientist Paul Newman of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Natural fluctuations in weather patterns resulted in warmer stratospheric temperatures this year. These temperatures led to a smaller ozone hole.”

The ozone layer acts as Earth’s natural shield against ultraviolet radiation, which can cause skin cancer. The ozone hole phenomenon began making a yearly appearance in the early 1980s. The Antarctic ozone layer likely will not return to its early 1980s state until about 2065, Newman said. The lengthy recovery is because of the long lifetimes of ozone-depleting substances in the atmosphere. Overall atmospheric ozone no longer is declining as concentrations of ozone-depleting substances decrease. The decrease is the result of an international agreement regulating the production of certain chemicals.

This year also showed a change in the concentration of ozone over the Antarctic. The minimum value of total ozone in the ozone hole was the second highest level in two decades. Total ozone, measured in Dobson units, reached 124 DU on Oct. 1. NOAA ground-based measurements at the South Pole recorded 136 DU on Oct. 5. When the ozone hole is not present, total ozone typically ranges from 240-500 DU.

This is the first year growth of the ozone hole has been observed by an ozone-monitoring instrument on the Suomi National Polar-orbiting Partnership (NPP) satellite. The instrument, called the Ozone Mapping Profiler Suite, is based on previous instruments, such as the Total Ozone Mapping Spectrometer and the Solar Backscatter Ultraviolet instrument, which have flown on multiple satellites. OMPS continues a satellite record dating back to the early 1970s.

In addition to observing the annual formation and extent of the ozone hole, scientists hope OMPS will help them better understand ozone destruction in the middle and upper stratosphere with its Nadir Profiler. Ozone variations in the lower stratosphere will be measured with its Limb Profiler.

“OMPS Limb looks sideways, and it can measure ozone as a function of height,” said Pawan K. Bhartia, a NASA atmospheric physicist and OMPS Limb instrument lead. “This OMPS instrument allows us to more closely see the vertical development of Antarctic ozone depletion in the lower stratosphere where the ozone hole occurs.”

NASA and NOAA have been monitoring the ozone layer on the ground and with a variety of instruments on satellites and balloons since the 1970s. Long-term ozone monitoring instruments have included TOMS, SBUV/2, Stratospheric Aerosol and Gas Experiment series of instruments, the Microwave Limb Sounder, the Ozone Monitoring Instrument, and the OMPS instrument on Suomi NPP. Suomi NPP is a bridging mission leading to the next-generation polar-orbiting environmental satellites called the Joint Polar Satellite System, will extend ozone monitoring into the 2030s.

NASA and NOAA have a mandate under the Clean Air Act to monitor ozone-depleting gases and stratospheric depletion of ozone. NOAA complies with this mandate by monitoring ozone via ground and satellite measurements. The NOAA Earth System Research Laboratory in Boulder, Colo., performs the ground-based monitoring. The Climate Prediction Center performs the satellite monitoring.

 

To monitor the state of the ozone layer above Antarctica, visit http://ozonewatch.gsfc.nasa.gov.

 




All of this week's top headlines to your email every Friday.


 
 

 

Headlines January 28, 2015

News: Panel will propose new military retirement system - The long-awaited report on military compensation set to drop Thursday will propose fundamental changes to military retirement and health care benefits, according to several people familiar with the report. Source: DOD to request $585 billion for fiscal 2016 - The Department of Defense is preparing to submit a...
 
 

News Briefs January 28, 2015

Defense contractor to pay $2 million to settle claims A Northern California defense contractor will pay the federal government $2 million to settle claims about its manufacturing of parts for remote-controlled aircraft. The U.S. Attorney’s Office in Sacramento says Sacramento-based Composite Engineering Inc. agreed to pay the money to end allegations that it artificially inflated...
 
 
Navy photograph

USS Roosevelt marks 200,000 trap

Navy photograph An F/A-18F Super Hornet flown by Capt. Daniel Grieco, commanding officer of the aircraft carrier USS Theodore Roosevelt (CVN 71), and Capt. Benjamin Hewlett, deputy commander of Carrier Air Wing (CVW) 1, complet...
 

 
Navy photograph by PO1 William Larned

USS California returns from maiden deployment

Navy photograph by PO1 William Larned The Virginia-class attack submarine USS California (SSN 781) returns from its maiden deployment to its homeport at Naval Submarine Base New London. Under the command of Cmdr. Shawn Huey, Ca...
 
 
Army photograph

Army proves new watercraft capabilities

Army photograph Marine Corps assets are loaded onto the USNS Sgt. Matej Kocak (T-AK 3005), from an U.S. Army Landing Craft Utility, or LCU, USAV Port Hudson during port operations, at White Beach Naval Base, Jan. 22, 2015. Sold...
 
 

Orbital stockholders approve merger with ATK’s aerospace, defense groups

Orbital Sciences Corporation announced Jan. 27 that at a special meeting, the company’s stockholders voted overwhelmingly to approve the proposed merger with the Aerospace and Defense Groups of Alliant Techsystems Inc., pursuant to the definitive transaction agreement dated April 28, 2014. Approximately 99 percent of the votes cast at the special meeting voted in favor...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>