Subscribe free to our newsletters via your
. 24/7 Space News .




OZONE NEWS
Ozone hole might slightly warm planet
by Staff Writers
Washington DC (SPX) Aug 15, 2013


A map of ozone concentrations in the Southern Hemisphere shows thinning of the ozone layer over the South Pole. This region of reduced ozone, which is called the "ozone hole," causes changes in wind patterns and cloud cover. Credit: NASA.

A lot of people mix up the ozone hole and global warming, believing the hole is a major cause of the world's increasing average temperature. Scientists, on the other hand, have long attributed a small cooling effect to the ozone shortage in the hole.

Now a new computer-modeling study suggests that the ozone hole might actually have a slight warming influence, but because of its effect on winds, not temperatures. The new research suggests that shifting wind patterns caused by the ozone hole push clouds farther toward the South Pole, reducing the amount of radiation the clouds reflect and possibly causing a bit of warming rather than cooling.

"We were surprised this effect happened just by shifting the jet stream and the clouds," said lead author Kevin Grise, a climate scientist at Lamont-Doherty Earth Observatory of Columbia University in New York City.

Grise notes this small warming effect may be important for climatologists trying to predict the future of Southern Hemisphere climate.

The work is detailed in Geophysical Research Letters, a journal of the American Geophysical Union. Grise collaborated on the study with Lorenzo Polvani of Columbia University, George Tselioudis of NASA Goddard Institute for Space Studies, Yutian Wu of New York University, and Mark Zelinka of Lawrence Livermore National Laboratory.

Hole in the sky
Each ozone molecule consists of three oxygen atoms bound together. These ozone molecules gather in the lower portion of the stratosphere about 20 to 30 kilometers (12 to 19 miles) above the ground-about twice as high as commercial airliners fly.

Thankfully for the living things below, this layer of ozone shields Earth from some of the hazardous ultraviolet radiation barraging the atmosphere. Unchecked, these ultraviolet rays can cause sunburns, eye damage and even skin cancer.

In the 1980s, scientists discovered thinning of the ozone layer above Antarctica during the Southern Hemisphere's spring months. The cause of this "hole" turned out to be chlorofluorocarbons, such as Freon, from cooling systems, aerosols cans and degreasing solvents, which break apart ozone molecules. Even though the1987 Montreal Protocol banned these chlorofluorocarbons worldwide, the ozone hole persists decades later.

Many people falsely equate the ozone hole to global warming. In a 2010 Yale University poll, 61 percent of those surveyed believed the ozone hole significantly contributed to global warming. Additionally, 43 percent agreed with the statement "if we stopped punching holes in the ozone layer with rockets, it would reduce global warming".

An actual consequence of the ozone hole is its odd effect on the Southern Hemisphere polar jet stream, the fast flowing air currents encircling the South Pole. Despite the ozone hole only appearing during the spring months, throughout each subsequent summer the high-speed jet stream swings south toward the pole.

"For some reason when you put an ozone hole in the Southern Hemisphere during springtime, you get this robust poleward shift in the jet stream during the following summer season," said Grise. "People have been looking at this for 10 years and there's still no real answer of why this happens."

Cloud reflection
The team of scientists led by Grise wondered if the ozone hole's impacts on the jet stream would have any indirect effects on the cloud cover. Using computer models, they worked out how the clouds would react to changing winds.

"Because the jet stream shifts, the storm systems move along with it toward the pole," said Grise. "If the storm systems move, the cloud system is going to move with it."

High- and mid-level clouds, the team discovered, traveled with the shifting jet stream toward the South Pole and the Antarctic continent. Low-level cloud coverage dropped in their models throughout the Southern Ocean.

While modeling clouds is a difficult task due to the variety of factors that guide their formation and movement, Grise noted that observational evidence from the International Satellite Cloud Climatology Project, a decades-long NASA effort to map global cloud distributions, supports their theory of migrating cloud coverage.

When the cloud cover moves poleward, the amount of energy the clouds can reflect drops, which increases the amount of radiation reaching the ground. "If you shift the reflector poleward," Grise explained, "you've moved it somewhere there is less radiation coming in."

In 2007, the Intergovernmental Panel on Climate Change reported a direct cooling effect from the thinning ozone layer-specifically, a reduction of about 0.05 watts per square meter's worth of energy reaching the ground.

However, Grise and his colleagues estimated the indirect effect of the shifting cloud coverage to be an increase of approximately 0.2 watts per square meter. Their result not only suggests that warming rather than cooling would be taking place, but also that there's a larger influence overall. Since the jet stream only shifts during the summer months, the warming only takes place in those months.

"Theoretically this net radiation input into the system should give some sort of temperature increase, but it's unknown if that signal could be detected or what the magnitude of it would be," said Grise. For comparison, worldwide, an average of about 175 watts per square meter reaches the ground from sunlight, according to the George Washington University Solar Institute.

Dennis Hartmann, an atmospheric scientist at the University of Washington in Seattle unrelated with the project, points out that since predicting cloud behavior is so challenging, the model used in Grise's study could be underestimating clouds north of the jet stream being pulled toward the equator and in turn reflecting more light, potentially reducing or even negating the warming effect. Hartmann added that he also has some concerns about the modeling of the low-level cloud response.

Still, "this is certainly a very interesting topic and potentially important from a practical perspective of predicting Southern Hemisphere climate and even global warming rates," he commented.

Climate tug-of-war
Looking toward the future, the jet stream should do less and less shifting to the south during the summer months as the ozone layer above the South Pole recovers. However, increasing levels of greenhouse gases can also change mid-latitude wind patterns and push the jet stream poleward, creating a complicated scenario which Grise said he plans to study in future work.

"You have sort of this tug-of-war between the jet being pulled equator-ward during the summer because of the ozone recovery and the greenhouse gases pulling the jet further poleward," said Grise. "What the clouds do in that scenario is an open question."

Funding for the research was provided by the National Science Foundation and by the U.S. Department of Energy's Office of Science.

.


Related Links
Lamont-Doherty Earth Observatory of Columbia University
All about the Ozone Layer






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





OZONE NEWS
Ozone-protection treaty had climate benefits
New York NY (SPX) Aug 07, 2013
The global treaty that headed off destruction of earth's protective ozone layer has also prevented major disruption of global rainfall patterns, even though that was not a motivation for the treaty, according to a new study in the Journal of Climate. The 1987 Montreal Protocol phased out the use of chloroflourocarbons, or CFCs, a class of chemicals that destroy ozone in the stratosphere, a ... read more


OZONE NEWS
NASA Selects Launch Services Contract for OSIRIS-REx Mission

Environmental Controls Move Beyond Earth

Bad night's sleep? The moon could be to blame

Moon Base and Beyond

OZONE NEWS
MRO Swapping Motion-Sensing Units

Opportunity Reaches Base of 'Solander Point'

NASA launches new Russian-language Mars website

Big ice may explain Mars' double-layer craters

OZONE NEWS
Voyager 1 Has Left the Solar System

NASA Voyager Statement about Competing Models to Explain Recent Spacecraft Data

NASA Commercial Crew Partner SpaceX Completes Orbit and Entry Review

Space to become tourist destination in the future

OZONE NEWS
China launches three experimental satellites

Medical quarantine over for Shenzhou-10 astronauts

China's astronauts ready for longer missions

Chinese probe reaches record height in space travel

OZONE NEWS
ISS Boosting Biological Research in Orbit

Japanese Cargo Craft Captured, Berthed to ISS

Japanese Cargo Spacecraft Docks with ISS

NASA's Firestation on way to ISS

OZONE NEWS
Lockheed Martin Selects CubeSat Integrators for Athena to Enhance Launch Systems Integration

Russia to resume Proton-M rocket launches in mid-September

Roscosmos denies plans to launch Proton rocket from Baikonur on Sept 15

SpaceX rocket launches, steers and lands in test

OZONE NEWS
Distant planet sets speed record by orbiting its star every 8.5 hours

Kepler planet hunter spacecraft is beyond repair: NASA

Astronomers Image Lowest-mass Exoplanet Around a Sun-like Star

New Explorer Mission Chooses the 'Just-Right' Orbit

OZONE NEWS
Space station astronauts to be provided with 3-D printer to make parts

Advancing resistive memory to improve portable electronics

ORNL superconducting wire yields unprecedented performance

A new approach assembles big structures from small interlocking pieces




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement