Jacques van Oene
December 7th 05, 04:09 AM
December 6, 2005
George Deutsch/Erica Hupp
Headquarters, Washington
(202) 358-1324/1237
Rob Gutro/Steve Cole
Goddard Space Flight Center, Greenbelt, Md.
(301) 286-4044/3026
RELEASE: 05-434
NASA'S AURA SATELLITE PEERS INTO EARTH'S OZONE HOLE
NASA researchers, using data from the agency's AURA satellite,
determined the seasonal ozone hole that developed over Antarctica
this year is smaller than in previous years.
NASA's 2005 assessment of the size and thickness of the ozone layer
was the first based on observations from the Ozone Monitoring
Instrument on the agency's Aura spacecraft. Aura was launched in
2004.
This year's ozone hole measured 9.4 million square miles at its peak
between September and mid-October, which was slightly larger than
last year's peak. The size of the ozone hole in 1998, the largest
ever recorded, averaged 10.1 million square miles. For 10 of the past
12 years, the Antarctic ozone hole has been larger than 7.7 million
square miles. Before 1985, it measured less than 4 million square
miles.
The protective ozone layer over Antarctica annually undergoes a
seasonal change, but since the first satellite measurements in 1979,
the ozone hole has gotten larger. Human-produced chlorine and bromine
chemicals can lead to the destruction of ozone in the stratosphere.
By international agreement, these damaging chemicals were banned in
1995, and their levels in the atmosphere are decreasing.
Another important factor in how much ozone is destroyed each year is
the temperature of the air high in the atmosphere. As with
temperatures on the ground, some years are colder than others. When
it's colder in the stratosphere, more ozone is destroyed. The 2005
ozone hole was approximately 386,000 square miles larger than it
would have been in a year with normal temperatures, because it was
colder than average. Only twice in the last decade has the ozone hole
shrunk to the size it typically was in the late 1980s. Those years,
2002 and 2004, were the warmest of the period.
Scientists also monitor how much ozone there is in the atmosphere from
the ground to space. The thickness of the Antarctic ozone layer was
the third highest of the last decade, as measured by the lowest
reading recorded during the year. The level was 102 Dobson Units (the
system of measurement designated to gauge ozone thickness). That is
approximately one-half as thick as the layer before 1980 during the
same time of year.
The Ozone Monitoring Instrument is the latest in a series of
ozone-observing instruments flown by NASA over the last two decades.
This instrument provides a more detailed view of ozone and is also
able to monitor chemicals involved in ozone destruction. The
instrument is a contribution to the mission from the Netherlands'
Agency for Aerospace Programs in collaboration with the Finnish
Meteorological Institute. The Royal Netherlands Meteorological
Institute is the principal investigator on the instrument.
For images related to this story on the Web, visit:
http://www.nasa.gov/vision/earth/lookingatearth/ozone_five.html
For more information on NASA's Aura mission on the Web, visit:
http://www.nasa.gov/aura
For more information about NASA and agency programs on the Web, visit:
http://www.nasa.gov/home
-end-
--
--------------
Jacques :-)
www.spacepatches.info
George Deutsch/Erica Hupp
Headquarters, Washington
(202) 358-1324/1237
Rob Gutro/Steve Cole
Goddard Space Flight Center, Greenbelt, Md.
(301) 286-4044/3026
RELEASE: 05-434
NASA'S AURA SATELLITE PEERS INTO EARTH'S OZONE HOLE
NASA researchers, using data from the agency's AURA satellite,
determined the seasonal ozone hole that developed over Antarctica
this year is smaller than in previous years.
NASA's 2005 assessment of the size and thickness of the ozone layer
was the first based on observations from the Ozone Monitoring
Instrument on the agency's Aura spacecraft. Aura was launched in
2004.
This year's ozone hole measured 9.4 million square miles at its peak
between September and mid-October, which was slightly larger than
last year's peak. The size of the ozone hole in 1998, the largest
ever recorded, averaged 10.1 million square miles. For 10 of the past
12 years, the Antarctic ozone hole has been larger than 7.7 million
square miles. Before 1985, it measured less than 4 million square
miles.
The protective ozone layer over Antarctica annually undergoes a
seasonal change, but since the first satellite measurements in 1979,
the ozone hole has gotten larger. Human-produced chlorine and bromine
chemicals can lead to the destruction of ozone in the stratosphere.
By international agreement, these damaging chemicals were banned in
1995, and their levels in the atmosphere are decreasing.
Another important factor in how much ozone is destroyed each year is
the temperature of the air high in the atmosphere. As with
temperatures on the ground, some years are colder than others. When
it's colder in the stratosphere, more ozone is destroyed. The 2005
ozone hole was approximately 386,000 square miles larger than it
would have been in a year with normal temperatures, because it was
colder than average. Only twice in the last decade has the ozone hole
shrunk to the size it typically was in the late 1980s. Those years,
2002 and 2004, were the warmest of the period.
Scientists also monitor how much ozone there is in the atmosphere from
the ground to space. The thickness of the Antarctic ozone layer was
the third highest of the last decade, as measured by the lowest
reading recorded during the year. The level was 102 Dobson Units (the
system of measurement designated to gauge ozone thickness). That is
approximately one-half as thick as the layer before 1980 during the
same time of year.
The Ozone Monitoring Instrument is the latest in a series of
ozone-observing instruments flown by NASA over the last two decades.
This instrument provides a more detailed view of ozone and is also
able to monitor chemicals involved in ozone destruction. The
instrument is a contribution to the mission from the Netherlands'
Agency for Aerospace Programs in collaboration with the Finnish
Meteorological Institute. The Royal Netherlands Meteorological
Institute is the principal investigator on the instrument.
For images related to this story on the Web, visit:
http://www.nasa.gov/vision/earth/lookingatearth/ozone_five.html
For more information on NASA's Aura mission on the Web, visit:
http://www.nasa.gov/aura
For more information about NASA and agency programs on the Web, visit:
http://www.nasa.gov/home
-end-
--
--------------
Jacques :-)
www.spacepatches.info