Featured Research

from universities, journals, and other organizations

2001 Ozone Hole About The Same Size As Past Three Years

Date:
October 17, 2001
Source:
NASA/Goddard Space Flight Center
Summary:
Satellite data show the area of this year's Antarctic ozone hole peaked at about 26 million square kilometers -- roughly the size of North America -- making the hole similar in size to those of the past three years, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Researchers have observed a leveling-off of the hole size and predict a slow recovery.

Satellite data show the area of this year's Antarctic ozone hole peaked at about 26 million square kilometers -- roughly the size of North America -- making the hole similar in size to those of the past three years, according to scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA). Researchers have observed a leveling-off of the hole size and predict a slow recovery.

Over the past several years the annual ozone hole over Antarctica has remained about the same in both its size and in the thickness of the ozone layer. "This is consistent with human-produced chlorine compounds that destroy ozone reaching their peak concentrations in the atmosphere, leveling off, and now beginning a very slow decline," said Samuel Oltmans of NOAA's Climate Monitoring and Diagnostics Laboratory, Boulder, Colo.

In the near future -- barring unusual events such as explosive volcanic eruptions -- the severity of the ozone hole will likely remain similar to what has been seen in recent years, with year-to-year differences associated with meteorological variability. Over the longer term (30-50 years) the severity of the ozone hole in Antarctica is expected to decrease as chlorine levels in the atmosphere decline.

The total area of the ozone hole is one measure of its severity. The ozone hole area is defined as the size of the region with total ozone below 220 Dobson units. A Dobson unit is a unit of measurement that describes the thickness of the ozone layer in a column directly above the location being measured, a quantity called the "total column ozone amount."

Prior to the springtime period in Antarctica, when ozone depletion occurs, the normal ozone reading is around 275 Dobson units. "Last year the ozone hole was of record size, but it formed very early and then collapsed quickly," said NASA scientist R.D. McPeters of the Goddard Space Flight Center, Greenbelt, Md. "This year the hole was about 10 percent smaller."

Data from NOAA's polar-orbiting operational environmental satellites and estimates of the area made by NASA scientists using measurements from the Total Ozone Mapping Spectrometer aboard NASA's Earth Probe satellite give similar sizes.

Each spring when the Sun rises over Antarctica, chemical reactions involving chlorine and bromine from man-made CFCs (chlorofluorocarbons) and bromine-containing compounds occur in the stratosphere and destroy ozone, causing the "ozone hole." Measurements of this year's ozone hole made at the South Pole and above the Antarctic show that atmospheric ozone depletion reached levels typical of the past 10 years.

Using instrumented balloons to make ozone-profile measurements at the South Pole, researchers from NOAA reported that the September decline in ozone was similar to recent years with almost all of the ozone in the 15-20 kilometer (9-12 mile) altitude region destroyed.

"Total column ozone over the South Pole reached a minimum reading of 100 Dobson units on Sept. 28, 2001, compared to a minimum of 98 Dobson units in 2000," said Bryan Johnson, a scientist with the Climate Monitoring and Diagnostics Laboratory. The record low of 88 Dobson units was observed in 1993.

"The severity of the ozone depletion within the hole reached about the same levels as the past few years and the highly depleted region filled about three-fourths of the Antarctic polar vortex," said Jim Miller, a scientist with NOAA's Climate Prediction Center in Camp Springs, Md. "This year the vortex has been more stable and somewhat colder than average." Year-to-year fluctuations in the geographical size of the polar vortex and the size of the region with low temperatures will alter the size of the ozone hole over the next decade during the period that levels of ozone-destroying chemicals in the atmosphere begin a slow decline.

Thinning of the ozone layer is a concern because the ozone layer protects the Earth from harmful effects of the Sun's ultraviolet radiation, which contributes to skin cancer and cataracts in humans. Total recovery of the ozone layer to levels observed before 1980 will take at least 50 years, and expected changes in climate, including a cooler stratosphere, could delay this process. NASA is committed to obtaining critically important observations to examine and document the recovery of this life-protecting atmospheric gas.


Story Source:

The above story is based on materials provided by NASA/Goddard Space Flight Center. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Goddard Space Flight Center. "2001 Ozone Hole About The Same Size As Past Three Years." ScienceDaily. ScienceDaily, 17 October 2001. <www.sciencedaily.com/releases/2001/10/011017064540.htm>.
NASA/Goddard Space Flight Center. (2001, October 17). 2001 Ozone Hole About The Same Size As Past Three Years. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2001/10/011017064540.htm
NASA/Goddard Space Flight Center. "2001 Ozone Hole About The Same Size As Past Three Years." ScienceDaily. www.sciencedaily.com/releases/2001/10/011017064540.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins