Sunlit snow triggers atmospheric cleaning, ozone depletion in the Arctic

Apr. 24, 2013 ? National Science Foundation-funded researchers at Purdue University have discovered that sunlit snow is the major source of atmospheric bromine in the Arctic, the key to unique chemical reactions that purge pollutants and destroy ozone.

The new research also indicates that the surface snowpack above Arctic sea ice plays a previously unappreciated role in the bromine cycle and that loss of sea ice, which been occurring at an increasingly rapid pace in recent years, could have extremely disruptive effects in the balance of atmospheric chemistry in high latitudes.

The team's findings suggest the rapidly changing Arctic climate--where surface temperatures are rising three times faster than the global average--could dramatically change its atmospheric chemistry, said Paul Shepson, an NSF-funded researcher who led the research team. The experiments were conducted by Kerri Pratt, a postdoctoral researcher funded by the Division of Polar Programs in NSF's Geosciences Directorate.

"We are racing to understand exactly what happens in the Arctic and how it affects the planet because it is a delicate balance when it comes to an atmosphere that is hospitable to human life," said Shepson, who also is a founding member of the Purdue Climate Change Research Center. "The composition of the atmosphere determines air temperatures, weather patterns and is responsible for chemical reactions that clean the air of pollutants."

A paper detailing the results of the research, some of which was funded by NSF and some by the National Aeronautics and Space Administration, was recently published online at Nature Geoscience.

Ozone in the lower atmosphere behaves differently from the stratospheric ozone involved in the planet's protective ozone layer. This lower atmosphere ozone is a greenhouse gas that is toxic to humans and plants, but it also is an essential cleaning agent of the atmosphere.

Interactions between sunlight, ozone and water vapor create an "oxidizing agent" that scrubs the atmosphere of most of the pollutants human activity releases into it, Shepson said.

Temperatures at the poles are too cold for the existence of much water vapor and in the Arctic this cleaning process appears instead to rely on reactions on frozen surfaces involving molecular bromine, a halogen gas derived from sea salt.

This gaseous bromine reacts with and destroys atmospheric ozone. This aspect of the bromine chemistry works so efficiently in the Arctic that ozone is often entirely depleted from the atmosphere above sea ice in the spring, Shepson noted.

"This is just a part of atmospheric ozone chemistry that we don't understand very well, and this unique Arctic chemistry teaches us about the potential role of bromine in other parts of the planet," he said. "Bromine chemistry mediates the amount of ozone, but it is dependent on snow and sea ice, which means climate change may have important feedbacks with ozone chemistry."

While it was known that there is more atmospheric bromine in polar regions, the specific source of the natural gaseous bromine has remained in question for several decades, said Pratt, a Polar Programs-funded postdoctoral fellow and lead author of the paper.

"We thought that the fastest and best way to understand what is happening in the Arctic was to go there and do the experiments right where the chemistry is happening," Pratt said.

She and Purdue graduate student Kyle Custard performed the experiments in -45 to -34 Celsius (-50 to -30 Fahrenheit) wind chills near Barrow, Alaska. The team examined first-year sea ice, salty icicles and snow and found that the source of the bromine gas was the top surface snow above both sea ice and tundra.

"Sea ice had been thought to be the source of the gaseous bromine," she said. "We had an 'of course!' moment when we realized it was the snow on top of the sea ice. The snow is what is in direct contact with the atmosphere. Sea ice is critical to the process, though. Without it, the snow would fall into the ocean, and this chemistry wouldn't take place. This is among the reasons why the loss of sea ice in the Arctic will directly impact atmospheric chemistry."

The team also discovered that sunlight triggered the release of bromine gas from the snow and the presence of ozone increased the production of bromine gas.

"Salts from the ocean and acids from a layer of smog called Arctic haze meet on the frozen surface of the snow, and this unique chemistry occurs," Pratt said. "It is the interface of the snow and atmosphere that is the key."

A series of chemical reactions that quickly multiplies the amount of bromine gas present, called the "bromine explosion," is known to occur in the atmosphere. The team suggests this also occurs in the spaces between the snow crystals and wind then releases the bromine gas up into the air above the snow.

The team performed 10 experiments with snow and ice samples contained in a "snow chamber," a box constructed of aluminum with a special coating to prevent surface reactions and a clear acrylic top. Clean air with and without ozone was allowed to flow through the chamber and experiments were performed in darkness and in natural sunlight.

The team also measured the levels of bromine monoxide, a compound formed from the reaction of bromine atoms with ozone, through flights of the Purdue Airborne Laboratory for Atmospheric Research.

Shepson is the pilot of this specially equipped aircraft, which he and air operations technical specialist Brian Stirm flew from Indiana to Barrow for these experiments. They found the compound was most prevalent over snow-covered first-year sea ice and tundra, consistent with their snow chamber experiments.

The experiments were performed from March to April 2012 and were part of NASA's Bromine, Ozone and Mercury Experiment, or BROMEX. The goal of the study is to understand the implications of Arctic sea ice reduction on tropospheric chemistry.

Shepson's group next plans to perform laboratory studies to test the proposed reaction mechanisms and to return to Barrow to perform more snow chamber experiments.

In addition, Shepson is co-leading a team using ice-tethered buoys to measure carbon dioxide, ozone and bromine monoxide across the Arctic Ocean, and Pratt is working with scientists from the University of Washington to examine the chemistry of snow from across the Arctic Ocean.

"In the Arctic, climate change is happening at an accelerated pace," Pratt said. "A big question is what will happen to atmospheric composition in the Arctic as the temperatures rise and snow and ice decline even further?"

Share this story on Facebook, Twitter, and Google:

Other social bookmarking and sharing tools:

---

Story Source:

The above story is reprinted from materials provided by National Science Foundation.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

---

Journal Reference:

1. Kerri A. Pratt, Kyle D. Custard, Paul B. Shepson, Thomas A. Douglas, Denis P?hler, Stephan General, Johannes Zielcke, William R. Simpson, Ulrich Platt, David J. Tanner, L. Gregory Huey, Mark Carlsen, Brian H. Stirm. Photochemical production of molecular bromine in Arctic surface snowpacks. Nature Geoscience, 2013; DOI: 10.1038/ngeo1779

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/top_science/~3/otnt1-kVBHM/130424112305.htm

Pat Summerall Martin Richard Bbc News friends tracy mcgrady tracy mcgrady awkward

Man Arrested For "Mr. Right" T-Shirt, Refusal to Leave Park

Source: http://www.thehollywoodgossip.com/2013/04/man-arrested-for-mr-right-t-shirt-refusal-to-leave-park/

wilson chandler bristol motor speedway prometheus grand canyon skywalk tonga pid corned beef hash

HBT: Pujols says he's 'hurting real bad'

You?d never know it if you looked at his stats ? the Angels? slugger is hitting .317 with eight extra-base hits ? but Albert Pujols has been bothered by plantar fasciitis in his left foot. With another start at DH this afternoon, he has now started more games as the DH (nine) than as the first baseman (eight). Pujols himself admits the injury is bothering him.

?I?m dying,? Pujols said according to Bill Shaikin. ?It?s hurting real bad.?

The Angels will continue to use Pujols until he cannot handle the pain anymore.

?You?re always picking at a scab a little bit, when you?re trying to play and trying to run,? Manager Mike Scioscia said. ?Certainly, you don?t want it to regress. He?s swinging the bat real well.

?You want to keep it to where he can still DH and hopefully get him to first base at some point.?

The Angels have used Mark Trumbo at first base when Pujols has been the DH, which should be the case for the foreseeable future.

Source: http://hardballtalk.nbcsports.com/2013/04/21/albert-pujols-is-hurting-real-bad/related/

national enquirer whitney houston

George's big game leads Pacers past Atlanta 107-90

Indiana Pacers' Tyler Hansbrough, left, goes to the basket against Atlanta Hawks' Ivan Johnson during the first half of Game 1 in the first round of the NBA basketball playoffs on Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Indiana Pacers' Tyler Hansbrough, left, goes to the basket against Atlanta Hawks' Ivan Johnson during the first half of Game 1 in the first round of the NBA basketball playoffs on Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Atlanta Hawks head coach Larry Drew shouts instructions during the first half of Game 1 in the first round of the NBA basketball playoffs against the Indiana Pacers, Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Atlanta Hawks' Al Horford (15) shoots against Indiana Pacers' David West during the first half of Game 1 in the first round of the NBA basketball playoffs on Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Atlanta Hawks' Al Horford, right, goes to the basket against Indiana Pacers' Jeff Pendergraph during the first half of Game 1 in the first round of the NBA basketball playoffs on Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

Atlanta Hawks' Jeff Teague (0) shoots against Indiana Pacers' David West during the first half of Game 1 in the first round of the NBA basketball playoffs on Sunday, April 21, 2013, in Indianapolis. (AP Photo/Darron Cummings)

INDIANAPOLIS (AP) ? Paul George scored 23 points and recorded his first playoff triple double, leading Indiana past Atlanta 107-90 for a 1-0 lead in the Eastern Conference series.

George made just 3 of 13 shots but was 17 of 18 from the free-throw line, had 11 rebounds and 12 assists. George Hill added 18 points despite playing with a left groin injury. It's the first time since 2006 that the Pacers have opened a playoff series with a win.

The best-of-seven series resumes Wednesday at Indy.

On Sunday, the Central Division champs played more like the team that was contending for the No. 2 seed rather than the one stumbling to five losses in its previous seven games.

Atlanta was led by Jeff Teague with 21 points and Josh Smith with 15.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/347875155d53465d95cec892aeb06419/Article_2013-04-21-BKN-Hawks-Pacers/id-9afdd72858314125a69a8fb2c2169127

60 minutes go daddy Tom Kenny Long Island Medium Alfonso Ribeiro adam sandler College Football Scoreboard

'Coelacanth' Genome Unlocked

The genes of this fish, sometimes called a living fossil, reveal much about the origins of tetrapods, the evolutionary line that gave rise to amphibians, birds and mammals

By Chris Woolston and Nature magazine

The African coelacanth is a close relative of the first fishes to venture onto land. Image: Flickr/Tetsushi Tsunemi

The South African fisherman who pulled a prehistoric-looking blue creature out of his net in 1938 had unwittingly snagged one of the zoological finds of the century: a 1.5-meter-long coelacanth, a type of fish that had been thought to have become extinct 70 million years earlier.

Since then, scientists have identified two species of coelacanth, one African and one Indonesian. With their fleshy, lobed fins ? complete with bones and joints ? and round, paddle-like tails, they look strikingly similar to the coelacanths that lived during the Cretaceous period, when dinosaurs still roamed Earth.

Now, an international team of scientists has sequenced and analyzed the genome of the African coelacanth, Latimeria chalumnae; the findings are reported on page 311.

Like lungfish, the other surviving lineage of lobe-finned fishes, coelacanths are actually more closely related to humans and other mammals than to ray-finned fishes such as tuna and trout. Ancient lobe fins were the first vertebrates to brave the land, and the coelacanth genome is expected to reveal much about the origins of tetrapods, the evolutionary line that gave rise to amphibians, reptiles, birds and mammals, says lead author Chris Amemiya, a biologist at the University of Washington in Seattle. ?The coelacanth is a cornerstone for our attempt to understand tetrapod evolution,? he says.

Ending one long-standing argument, analysis of the coelacanth genome clearly shows that it is not the closest living fishy relative to tetrapods, Amemiya says: that honor belongs to the lungfish. However, he adds, the lungfish genome is unlikely to be sequenced any time soon because it is much larger and more complicated than that of the coelacanth.

Although coelacanths are often called ?living fossils?, these fish haven?t really been frozen in time, says co-author Kerstin Lindblad-Toh, a comparative genomicist at Uppsala University in Sweden. Comparison of protein-coding genes in coelacanths with those of cartilaginous fishes shows that the coelacanths have been steadily accruing DNA changes.

But the rate of change has been remarkably slow. The latest analysis shows that the genes of modern coelacanths can themselves be considered living fossils, says James Noonan, a geneticist at Yale University in New Haven, Connecticut.

Scientists already had hints of the coelacanth?s sluggish evolution. In a 2012 study, researchers in Japan and Tanzania compared the DNA of the African and Indonesian coelacanths. Specifically, they looked at HOX genes, which help to guide embryonic development (K.?Higasa et al. Gene 505, 324?332; 2012). Even though the two species separated, by one estimate, perhaps 6?million years ago, their genes are remarkably similar. For these particular genes, the difference between the two species of coelacanth was about 11 times smaller than that between the HOX genes of humans and chimps, two species that parted ways perhaps 6?million to 8?million years ago.

Slow to change
It is impossible to say for sure, but the slow rate of coelacanth evolution could be due to a lack of natural-selection pressure, Lindblad-Toh says. Modern coelacanths, like their ancestors, ?live far down in the ocean, where life is pretty stable?, she says. ?We can hypothesize that there has been very little reason to change.? And it is possible that the slow genetic change explains why the fish show such a striking resemblance to their fossilized ancestors.

The analysis showed that not all parts of the coelacanth genome are slow to evolve. The genome has a large number of transposable elements ? non-coding parts of the genome that have an important role in gene regulation ? that have been moving around in the genome at a relatively rapid pace. Non-coding DNA could be a significant source of evolutionary change, Lindblad-Toh says. But Amemiya adds that, for now, the role of non-coding DNA in speciation is ?speculative?, and its significance in coelacanth evolution is not clear.

Source: http://rss.sciam.com/click.phdo?i=0f63e1669e1a2b2377b6e1eab3037b2f

Alois Bell Donna Savattere deer antler spray Jason London rick ross yahoo finance iOS 6.1

China's struggle to measure economy clouds outlook

BEIJING (AP) ? After China reported quarterly economic growth of 7.7 percent this week ? far above anemic U.S. and European performance ? global markets reacted by falling, wiping billions of dollars off stock prices.

The reason? Growth came in under the 8 percent expected by private sector forecasters who relied on Chinese trade and other data.

The market plunge highlighted complaints about the possible inaccuracy of Beijing's official data and the intense, possibly excessive importance traders attach to a handful of Chinese economic indicators.

What matters more than a difference of a few tenths of a percentage point in growth from quarter to quarter is whether Chinese leaders are allowing the private sector to flourish by reducing the role of state industry in the economy, said Ben Simpfendorfer, managing director of Silk Road Associates, a consulting firm in Hong Kong.

"There is an obsession with these GDP numbers, and what really matters at this point is reform," said Simpfendorfer, a former Royal Bank of Scotland economist.

China is watched especially closely because it is a major market for foreign goods from iron ore to smartphones and is relatively healthy, fueling hopes Chinese demand can help offset weakness in the U.S., Europe and Japan.

Confusion about how fast China is growing can hamper foreign and private companies in industries from construction to chemicals to consumer goods as they make plans for business and investment.

Beijing's problems in keeping track of its economy stem in part from the fact that while it is surpassed only by the United States in size, China is growing and changing much faster than any rich country.

An understaffed bureaucracy inherited from the era of central planning is struggling to keep up with changes in trade, finance, manufacturing and city growth. Chinese companies have an incentive to avoid taxes or boost export rebates by misreporting sales and profits. Secrecy surrounding the collection and processing of official statistics leaves open the possibility they might be altered for political reasons.

Foreign and private companies look at government data with skepticism. Many rely on watching their own industries and markets more closely. The government still is the only source for most nationwide data, but a growing number of banks and research firms are developing their own based on surveys of companies and consumers.

"I think everyone doing business in China is skeptical of the data," said analyst Alistair Thornton of IHS Global Insight.

Thornton said three of China's most closely watched yardsticks are rife with potential problems ? exports, real estate sales and credit.

Export data have gotten the most attention lately after some analysts suggested companies might be inflating values on customs declarations. That might be intended to let them evade currency controls and move money into China. Reporting rising prices while exporting the same amount of goods might give a false impression of higher production.

The customs agency defended itself this month, saying its reports were based on goods that really were exported. However, that would not prevent exporters from submitting inflated values for them.

March exports were "substantially lower than reported numbers," which might have helped lead to the discrepancy between GDP forecasts and the government report, said RBS economists Louis Kuijs and Tiffany Qiu in a report.

Monday's unexpected decline in reported growth from 7.9 percent in the final quarter of 2012 was severe enough that economists responded by cutting their growth outlook for China this year.

JP Morgan economist Hongbin Qu scaled back his forecast from 8.2 percent to a still-healthy 7.8 percent, while Kuijs and Qiu at RBS reduced theirs from 8.4 percent to 7.8 percent.

Data showing rising bank loans and other credit, another key indicator, also might be inflated, according to Thornton. He said official figures might mistakenly count the same money two, three or more times as credit is extended from one company to another and then to a third.

Government figures on home sales also might give a false picture of the strength of the housing market because they rely on seller-reported prices without independent measurement.

Chinese economic growth figures are, like those of other countries, estimates that are often revised later.

Unlike other countries, though, China's revisions can be huge. In 2009, Beijing raised its official 2007 growth rate from an already eye-popping 11.9 percent to 13 percent. That suggested its earlier estimate failed to take account of tens of billions of dollars in economic activity.

Economists also note that even where Chinese data are reliable, they can be pumped up by investment or government spending that might do little for long-term prosperity.

Chinese leaders are trying to nurture more self-sustaining growth based on domestic consumption rather than exports and investment. That will drag down the overall growth rate in the short run.

The World Bank and other advisers have warned that to keep growth strong, Beijing needs to curb the dominance of state industry and encourage free-market competition ? a factor that isn't reflected in the headline numbers.

On Monday, China's surprise growth hiccup triggered selling in Western and Asian stock markets. The Dow ended at 14,648, a drop of 1.4 percent and the Standard & Poor's 500 slumped 1.9 percent to 1,559.

Thornton noted that last week, global stocks rose after China's report of stronger March trade, even though analysts said the data probably were inaccurate and exports weaker than they appeared.

"We all know markets are not particularly rational and overshoot or undershoot and wipe billions of dollars off market cap off indices over what we think is a misreading of various data points," he said.

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/f70471f764144b2fab526d39972d37b3/Article_2013-04-16-AS-China-Data-Doubts/id-cd44582a33c04dfc9a8de6c7090df233

brandon inge freedom tower freedom tower eric church quick silver where have you been rihanna world trade center

Waqar Masood to lead finance ministry again ? The Express Tribune

Premie?r Khoso replac?es Sindh Chief Secret?ary Raja Abbas with Chaudh?ry Ijaz.

PM Khoso appoints Dr Chaudhry hours before a Pakistani team was scheduled to leave for the United States to attend IMF-World Bank spring meetings. PHOTO: AFP/ FILE

ISLAMABAD:?

Caretaker Prime Minister Mir Hazar Khan Khoso has brought Dr Waqar Masood ? the man who negotiated the last International Monetary Fund programme ? back into the finance ministry as finance secretary. An economics professor, Dr Shahid Amjad Chaudhry, was appointed as the premier?s adviser on finance.

The development came hours before a Pakistani team was scheduled to leave for the United States to attend IMF-World Bank spring meetings. Now, Dr Chaudhry will lead the delegation. Dr Masood, State Bank Governor Yaseen Anwar and the Economic Affairs Division secretary will accompany him. Dr Masood has replaced Nasir Khoso, who has been appointed as textiles secretary.

On the sidelines, the Pakistani team plans to hold talks with the IMF for a second bailout programme in five years. According to a finance ministry official, if both sides make some progress an IMF team will visit the country soon.

Analysts said Pakistan?s intention to seek a bailout programme is linked to the fast depleting foreign currency reserves due to payments made to the IMF. Jarringly, the reserves have depleted to $6.7 billion, including $2.3 billion that have already been pledged in forward contracts for imports. The current level of reserves, excluding forward contracts, can only supplement a one-month import bill which surged to $4.4 billion last month.

Previously, Dr Masood had held talks with the IMF for the $11.3 billion bailout programme signed in October 2008, for 25 months. However, it terminated prematurely, due to the inability of economic managers to implement taxation and energy reforms.

Also on Monday, Premier Khoso replaced Sindh Chief Secretary Raja Abbas with Chaudhry Ijaz, Secretary, National Harmony Ministry. According to an official statement, Abbas has been posted as secretary Board of Investment, a role that was previously being fulfilled by Ijaz.

Khoso has also approved the transfer of some other federal secretaries. Secretary Information Taimur Azmat Usman has been appointed secretary, ministry of food security. Usman replaced Ahmed Baksh Lehri, who now will serve as establishment secretary.

Published in The Express Tribune, April 16^th, 2013.

on Twitter, become a fan on Facebook

Source: http://tribune.com.pk/story/536172/waqar-masood-to-lead-finance-ministry-again/

the parent trap invisible children kony 2012 space weather sunspots pac 12 tournament sun storm tri