Inside the Ozone LayerFebruary 24, 2006Researchers quantify stratosphere damage with an eye toward ozone hole recovery A new atmospheric model is able to quantify man-made versus naturally occurring damage to the stratosphere with an eye toward repairing the diminishing ozone layer that is located within the stratosphere. That's the premise of a paper published in this week's Science titled, "Anthropogenic and Natural Influences in the Evolution of Lower Stratospheric Cooling." Ozone Researchers used a model to observe the stratosphere, the layer above the troposphere, and better understand what has contributed to its cooling over the past approximately 25 years. The stratosphere contains the ozone layer, which absorbs sunlight and heats the stratosphere. This long-term cooling trend is generally accepted to result from the loss of the ozone layer as a result of man-made influences. However, the cooling trend is not uniform like ozone loss, but rather broken into a series of jumps or discontinuities. These jumps are associated with major volcanic (El Chichon in 1982 and Mt. Pinatubo in 1991) eruptions that inject aerosols into the stratosphere. The aerosols also absorb sunlight and heat the stratosphere, thus temporarily offsetting the cooling trend from ozone loss. The volcanic eruptions are considered to be a "natural" forcing. The model that researchers used to evaluate the influences, both man-made and naturally occurring, included not only the ozone loss and volcanic eruptions, but also solar activity, and a few other variables that also affect stratospheric temperature. What they found was that when all these factors are included, the model does an excellent job of reproducing the observed cooling of the stratosphere over the record of satellite observation from 1980 to 2005 - both the long-term cooling trend and the jumps. "Since we can make this determination, it gives us confidence in the model's ability also to predict future cooling of the stratosphere over the next century from increasing greenhouse gases, such as carbon dioxide," said University of Miami Rosenstiel School's Dr. Brian Soden, who is among the paper's six authors. Venkatchalam Ramaswamy, from NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton NJ, is the lead author on this paper, which also includes the work of Soden, Dan Schwarzkopf from NOAA's GFDL, Bill Randel from the National Center for Atmospheric Research, Ben Santer from the Program for Climate Model Diagnosis and Intercomparison at Lawrence Livermore National Laboratory, and Georgiy Stenchikov at the Department of Environmental Sciences at Rutgers University. "While most people equate a warmer atmosphere with global warming, the stratosphere is a section of the atmosphere which actually cools in response to increasing greenhouse gases," Soden said. Increasing carbon dioxide warms the earth's surface and troposphere, but eventually it actually cools the stratosphere. In the next century, carbon dioxide will likely become the dominant contributor to stratospheric cooling. And, future stratospheric cooling, in turn, may have important implications for the rate of recovery of the ozone hole in the southern hemisphere and possibly even the loss of ozone over the polar regions of the northern hemisphere. University of Miami |
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| Related Ozone Layer Current Events and Ozone Layer News Articles A bubbling ball of gas The Sun is a bubbling mass. Packages of gas rise and sink, lending the sun its grainy surface structure, its granulation. Dark spots appear and disappear, clouds of matter dart up - and behind the whole thing are the magnetic fields, the engines of it all. Ozone layer depletion levelling off By merging more than a decade of atmospheric data from European satellites, scientists have compiled a homogeneous long-term ozone record that allows them to monitor total ozone trends on a global scale - and the findings look promising. Portable and precise gas sensor could monitor pollution and detect disease In the air, it is a serious pollutant. In the body, it plays a role in heart rate, blood flow, nerve signals and immune function. University of Toronto study shows climate change will lead to less ultraviolet radiation over northern high latitudes Physicists at the University of Toronto have discovered that changes in the Earth's ozone layer due to climate change will reduce the amount of ultraviolet (UV) radiation in northern high latitude regions such as Siberia, Scandinavia and northern Canada. NOAA study shows nitrous oxide now top ozone-depleting emission Nitrous oxide has now become the largest ozone-depleting substance emitted through human activities, and is expected to remain the largest throughout the 21st century, NOAA scientists say in a new study. The greenhouse gas that saved the world When Planet Earth was just cooling down from its fiery creation, the sun was faint and young. So faint that it should not have been able to keep the oceans of earth from freezing. But fortunately for the creation of life, water was kept liquid on our young planet. IAU0916: The violent youth of solar proxies steer course of genesis of life One of the hottest topics at this year's XXVIIth General Assembly of the International Astronomical Union (IAU) in Rio de Janeiro, Brazil involves the study of the astrophysical conditions favourable for the development and survival of primordial life. Beyond CO2: Study reveals growing importance of HFCs in climate warming Some of the substances that are helping to avert the destruction of the ozone layer could increasingly contribute to climate warming. Global sunscreen won't save corals Emergency plans to counteract global warming by artificially shading the Earth from incoming sunlight might lower the planet's temperature a few degrees, but such "geoengineering" solutions would do little to stop the acidification of the world oceans that threatens coral reefs and other marine life. Climate change and atmospheric circulation will make for uneven ozone recovery Earth's ozone layer should eventually recover from the unintended destruction brought on by the use of chlorofluorocarbons (CFCs) and similar ozone-depleting chemicals in the 20th century. More Ozone Layer Current Events and Ozone Layer News Articles |
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