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Arctic Ozone Loss
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NASA Leads Study of Unprecedented Arctic Ozone Loss

A NASA-led study has documented an unprecedented depletion of Earth's protective ozone layer above the Arctic last winter and spring caused by an unusually prolonged period of extremely low temperatures in the stratosphere.
The study, published online Sunday, Oct. 2, in the journal Nature, finds the amount of ozone destroyed in the Arctic in 2011 was comparable to that seen in some years in the Antarctic, where an ozone "hole" has formed each spring since the mid-1980s. The stratospheric ozone layer, extending from about 15 to 35 kilometers above the surface, protects life on Earth from the sun's harmful ultraviolet rays.
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Blobrana


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Ozone Hole
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Arctic ozone loss at record level

Ozone loss over the Arctic this year was so severe that for the first time it could be called an "ozone hole" like the Antarctic one, scientists report.
About 20km above the ground, 80% of the ozone was lost, they say.
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Blobrana


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NASA Study Sheds Light on Ozone Hole Chemistry

A new NASA study of Earth's polar ozone layer reinforces scientists' understanding of how human-produced chlorine chemicals involved in the destruction of ozone interact with each other.
A team of scientists led by Michelle Santee of NASA's Jet Propulsion Laboratory, Pasadena, Calif., examined how night time temperatures affect chlorine monoxide, a key chemical involved in ozone destruction. Combining NASA satellite measurements with a state-of-the-art chemical model, they found this relationship to be more consistent with recent laboratory work than with some older laboratory and field observational data. This verification is important, because scientists have not been able to conduct appropriate laboratory experiments relevant to understanding how polar chlorine monoxide behaves at night at the lowest temperatures of the stratosphere, Earth's second lowest atmospheric layer.
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Blobrana


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Ozone
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Study Links Spring Ozone Over North America With Emissions Abroad

Springtime ozone levels above western North America are rising, primarily due to air flowing eastward from the Pacific Ocean, a trend that is most significant when the air originates in Asia. These increases in ozone could make it more difficult for the United States to meet Clean Air Act standards for ozone pollution at ground level, according to a new international study published online Jan. 20 in the journal Nature.
The study led by the National Oceanic and Atmospheric Administration (NOAA) analysed large quantities of ozone data captured since 1984. Among the data sources for the study were profiles of ozone in Earth's troposphere (lowermost atmosphere) measured since 1999 by the differential absorption lidar (laser detection and ranging) system located at the NASA Jet Propulsion Laboratory Table Mountain Facility near Wrightwood, Calif. That remote, high-altitude facility enables research in atmospheric science, optical communication and astronomy. Measurements from atmospheric balloons launched from Table Mountain also contributed to the findings.

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Blobrana


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RE: Ozone Hole
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Plumes from rocket launches could be the world's next worrisome emissions, according to a new study that says solid-fuel rockets damage the ozone layer, allowing more harmful solar rays to reach Earth.
Thanks to international laws, ozone-depleting chemicals such as chlorofluorocarbons (CFCs) and methyl bromide have been slowly fading from the atmosphere.
But when solid-fuel rockets launch, they release chlorine gas directly into the stratosphere, where the chlorine reacts with oxygen to form ozone-destroying chlorine oxides.

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Blobrana


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Europe's new Metop satellite has revealed the extent of ozone thinning over Antarctica this year.
At its worst in late September, the hole was twice as big as Europe.
Nearly 200 governments recently agreed a faster timetable for phasing out the chemicals thought to be depleting the protective layer in the stratosphere.
This has been the first opportunity for Metop, Europe's most sophisticated weather and climate observer, to study the hole since its launch last year.

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Blobrana


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According to US government scientists, this year's Antarctic ozone hole is the biggest ever.
The so-called hole is a region where there is severe depletion of the layer of ozone - a form of oxygen - in the upper atmosphere that protects life on Earth by blocking the sun's ultraviolet rays.
Scientists say human-produced gases such as bromine and chlorine damage the layer, causing the hole. That's why many compounds such as spray-can propellants have been banned in recent years.

"From Sept. 21 to 30, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles" - Paul Newman, atmospheric scientist at NASA's Goddard Space Flight Centre.

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Blobrana


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Ozone measurements made by ESA’s Envisat satellite have revealed the ozone loss of 40 million tonnes on 2 October 2006 has exceeded the record ozone loss of about 39 million tonnes for 2000.

Ozone loss is derived by measuring the area and the depth of the ozone hole. The size of this year’s ozone hole is 28 million square km, nearly as large as the record ozone hole extension during 2000, and the depth of the ozone hole is around 100 Dobson Units, rivalling the record low ozone values in 1998. This year’s record ozone loss was reached because these two measurements occurred during the same time period. (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.)

antarcticozone
Expand (35kb, 560 x 608)
Credit NASA

This image from September 29, 2006, shows the ozone concentration in the stratosphere above the South Pole observed by the Ozone Monitoring Instrument on NASA’s Aura satellite. Greens and yellows show areas with the highest ozone amounts, while blues and purples show where ozone amounts are lowest. A purple veil of extremely low levels of ozone stretches across most of Antarctica, which is roughly centred in the image.

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Blobrana


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According to the World Meteorological Organization (WMO) the seasonal ozone hole over Antarctica has widened to a near-record size, at approximately 27 million square kilometres.

The record of 28 square kilometres was set in 2003.

The hole in the ozone layer is created by pollution and atmospheric conditions and fluctuates according to season.
Ozone, a molecule of oxygen, filters out dangerous ultraviolet rays from the Sun that damage vegetation and can cause skin cancer and cataracts.
The protective stratospheric layer has been increasingly damaged by man-made chemicals, especially chlorine and chlorofluorocarbons (CFCs).

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