Arctic clouds highly sensitive to air pollution

In 1870, explorer Adolf Erik Nordenskiöld, trekking across the barren and remote ice cap of Greenland, saw something most people wouldn't expect in such an empty, inhospitable landscape: haze.

Nordenskiöld's record of the haze was among the first evidence that air pollution around the northern hemisphere can travel toward the pole and degrade air quality in the Arctic. Now, a study from University of Utah atmospheric scientist Tim Garrett and colleagues finds that the air in the Arctic is extraordinarily sensitive to air pollution, and that particulate matter may spur Arctic cloud formation. These clouds, Garrett writes, can act as a blanket, further warming an already-changing Arctic.

"The Arctic climate is delicate, just as the ecosystems present there," Garrett says. "The clouds are right at the edge of their existence and they have a big impact on local climate. It looks like clouds there are especially sensitive to air pollution." The study is published in Geophysical Research Letters.

Pollution heading north

Garrett says that early Arctic explorers' notes show that air pollution has been traveling northward for nearly 150 years or more. "This pollution would naturally get blown northward because that's the dominant circulation pattern to move from lower latitudes toward the poles," he says. Once in the Arctic, the pollution becomes trapped under a temperature inversion, much like the inversions that Salt Lake City experiences every winter. In an inversion, a cap of warm air sits over a pool of cold air, preventing the accumulated bad air from escaping.

Others have studied which regions contribute to Arctic pollution. Northeast Asia is a significant contributor. So are sources in the far north of Europe. "They have far more direct access to the Arctic," Garrett says. "Pollution sources there don't get diluted throughout the atmosphere."

Scientists have been interested in the effects of pollution on Arctic clouds because of their potential warming effect. In other parts of the world, clouds can cool the surface because their white color reflects solar energy back out into space. "In the Arctic, the cooling effect isn't as large because the sea-ice at the surface is already bright," Garrett says. "Just as clouds reflect radiation efficiently, they also absorb radiation efficiently and re-emit that energy back to warm the surface." Droplets of water can form around particulate matter in the air. More particles make for more droplets, which makes for a cloud that warms the surface more.

Seeing through the clouds

But quantifying the relationship between air pollution and clouds has been difficult. Scientists can only sample air pollution in clouds by flying through them, a method that can't cover much ground or a long time period. Satellite images can detect aerosol pollution in the air -- but not through clouds. "We'll look at the clouds at one place and hope that the aerosols nearby are representative of the aerosols where the cloud is," says Garrett. "They're not going to be. The cloud is there because it's in a different meteorological air mass than where the clear sky is."

So Garrett and his colleagues, including U graduate Quentin Coopman, needed a different approach. Atmospheric models, it turns out, do a good job of tracking the movements of air pollution around the Earth. Using global inventories of pollution sources, they simulate air pollution plumes so that satellites can observe what happens when these modeled plumes interact with Arctic clouds. The model allowed the researchers to study air pollution and clouds at the same time and place and also take into account the meteorological conditions. They could be sure the effects they were seeing weren't just natural meteorological variations in normal cloud-forming conditions.

Highly sensitive clouds

The research team found that clouds in the Arctic were two to eight times more sensitive to air pollution than clouds at other latitudes. They don't know for sure why yet, but hypothesize it may have to do with the stillness of the Arctic air mass. Without the air turbulence seen at mid-latitudes, the Arctic air can be easily perturbed by airborne particulates.

One factor the clouds were not sensitive to, however, was smoke from forest fires. "It's not that forest fires don't have the potential," Garrett says, "it's just that the plumes from these fires didn't end up in the same place as clouds." Air pollution attributable to human activities outpaced the influence of forest fires on Arctic clouds by a factor of around 100:1.

This gives Garrett hope. Particulate matter is an airborne pollutant that can be controlled relatively easily, compared to pollutants like carbon dioxide. Controlling current particulate matter sources could ease pollution in the Arctic, decrease cloud cover, and slow down warming. All of those gains could be offset, other researchers have suggested, if the Arctic becomes a shipping route and sees industrialization and development. Emissions from those activities could have a disproportionate effect on Arctic clouds compared to emissions from other parts of the world, Garrett says.

"The Arctic is changing incredibly rapidly," he says. "Much more rapidly than the rest of the world, which is changing rapidly enough."

Russia eyes military icebreaker force to protect Arctic borders - report

The Russian Navy is reportedly considering the creation of a force of military icebreakers and ice-class attack ships based on the newest nuclear icebreakers. Their task would be security of the Northern Sea Route and protecting Russia’s Arctic borders.

The design of an ice-class attack vessel is being discussed with the military, Valery Polovinkin, adviser to the Krilov State Research Center, specializing in research into sophisticated maritime equipment, told Izvestia daily. It is likely that the ship will have a lot in common with the Leader project, a new-generation of Russian nuclear-powered super-icebreakers expected to enter the design phase in 2016.

Russian military plans mobile nuclear energy plants in Arctic by 2020

The CEO and chief constructor at the Center’s subsidiary developing Leader project, Aleksandr Ryzhkov, believes the new 205-meter-long super-icebreaker, powered by two 60 MWt RITM-400 next-generation nuclear reactors will have excessive power “to cross the North Pole in any direction, any time of the year, in any ice condition [thickness].”

The icebreaker’s power plant will have unprecedented operating capacity of crashing through 2-meter-thick ice at a speed of 14 knots, which is seven times faster than the nuclear icebreakers operating today.

“At a slower speed it will go through ice 4.5 meters thick,” Ryzhkov told Izvestia. “For navigating vessels on the traditional routes along the shore this is excessive.”

Although the Leader project is being designed for civilian use, “these days, this sector of shipbuilding is increasingly becoming a locomotive for the military taking relevant decisions,” Ryzhkov said.

The recent naval drills in the Arctic, which implied landing of troops on Kotelny Island (New Siberian Islands archipelago, located between the Laptev Sea and the East Siberian Sea, on the 75th parallel) has shown that even the presence of huge icebreakers powered with megawatts of nuclear power cannot guarantee the integrity of the hull of a standard military vessel operating in ice conditions. The vessels themselves need to be ‘ice-proof’ to be able to maintain Russia’s constant military presence in the Arctic region.

Russian President Vladimir Putin ordered a constant military presence in Arctic waters back in December 2013. This presence is necessary both for protecting the growing potential of the Europe-Asia transit gaining momentum on the Northern Sea Route and for maintaining Russia’s national security from the north.

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“If deployed to this [Arctic] area, American warships armed with BGM-109 Tomahawk long-range cruise missiles would have a firing range covering three-quarters of our territory, otherwise impenetrable from any other direction,” Polovinkin said.

Construction of a series of icebreakers to work with military vessels is already underway, with the first new generation diesel-electric icebreaker Ilya Muromets (Project 21180) - built at the Admiralty Shipyards in St. Petersburg - floated out in June.

However, the design of a typical icebreaker leaves no place for deployment of modern military hardware, such as radar and missile complexes, so an ice-class warship needs to be designed independently, keeping in mind specific hardware to be installed onboard to ensure its military capabilities.

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Arctic Ice Cap Is Smallest Since Late 1970s

WASHINGTON – The Arctic ice cap this year is the smallest it has been since the late 1970s, when satellite monitoring of the polar region began, and experts attribute the shrinkage to climate change and global warming, the National Oceanographic and Atmospheric Administration, or NOAA, reported Tuesday.

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