Mysterious 'Crater' in Antarctica Has Ominous Cause

A "crater" in Antarctica once thought to be the work of a meteorite impact is actually the result of ice melt, new research finds.

The hole, which is in the Roi Baudouin ice shelf in East Antarctica, is a collapsed lake — a cavity formed when a lake of meltwater drained — with a "moulin," a nearly vertical drainage passage through the ice, beneath it, researchers found on a field trip to the area in January 2016.

"That was a huge surprise," Stef Lhermitte, an earth science researcher at Delft University of Technology in the Netherlands and at the University of Leuven in Belgium, said in a statement. "Moulins typically are observed on Greenland. And we definitely never see them on an ice shelf." [See Photos of the Meltwater Lake Crater in Antarctica]

Surprising melt

Combining their fieldwork with satellite data and climate modeling, the researchers found that East Antarctica is more vulnerable to melt than was previously realized. Warm winds to the region blow away the snow cover, which darkens the surface of the ice, the team reported Dec. 12 in the journal Nature Climate Change. Darker surfaces absorb more heat from the sun than lighter surfaces, so they are more prone to melt. These floating ice sheets don't contribute much to sea level rise ­— as they're already in the ocean — but they provide an important backstop against the flowing of land-based ice from continental Antarctica into the ocean.

East Antarctica has been a mysterious place when it comes to climate change. The region has been gaining ice due to increases in snow accumulation, according to 2015 research. Global warming can increase snowfall by boosting the amount of moisture in the air (warm air holds more moisture than cold).

The Roi Baudouin crater was more mysterious still. It's existed on satellite images going back to at least 1989, researchers said, but was first noted widely in January 2015. Scientists initially reported it to be a meteorite crater, perhaps the result of a space rock that exploded over Antarctica in 2004. But scientists quickly questioned whether the 2-mile-wide (3 kilometers) circle was really from a meteorite. Many suspected it was the result of melting ice.

Jan Lenaerts, a climate researcher at Utrecht University in the Netherlands and at the University of Leuven, was one of the meteorite skeptics.

"My response was: 'In that area? Then it's definitely not a meteorite; it's proof of strong melting,'" he said in a statement.

Vulnerable ice

The new study confirms that hunch. During their fieldwork on the southernmost continent, researchers also discovered many other meltwater lakes beneath the surface of the Roi Baudouin ice sheet.

"The amount of meltwater differs immensely from year to year, but it clearly increases during warm years," Lhermitte said.

Earlier research had shown that West Antarctica is very sensitive to climate change, Lenaerts said in the statement.

"Our research now suggests that the much larger East Antarctica ice sheet is also very vulnerable," Lenaerts said.

Original article on Live Science.

62-Foot Wave Off Iceland Smashes World Record

A monstrous swell in the North Atlantic that rose up as high as a six-story building is now the world's tallest wave measured by a buoy, according to the World Meteorological Organization (WMO).

The wave crashed down the morning of Feb. 4, 2013, in the watery expanse between Iceland and the United Kingdom, at approximately 59 degrees N, 11 degrees W. It occurred after a strong cold front passed through the area, producing winds of up to 50.4 mph (43.8 knots), the WMO reported.

The North Atlantic is a prime setting for smashing big-wave records. The previous buoy-measured record of 59.96 feet (18.275 m) also occurred in the North Atlantic, on Dec. 8, 2007, as did the tallest wave measured from a ship — a 95.03-foot-tall (29.05 m) swell on Feb. 8, 2000, the organization said. [See Photos of Monstrous Ocean Waves]

"This is the first time we have ever measured a wave of 19 meters. It is a remarkable record," Wenjian Zhang, the assistant secretary-general of the WMO, said in a statement. "It highlights the importance of meteorological and ocean observations and forecasts to ensure the safety of the global maritime industry and to protect the lives of crew and passengers on busy shipping lanes."

The WMO added that the new record isn't from one wave, but rather an average of 10 to 15 wave heights, which "is a more reliable measure of wave height than that of a single wave," said Randall Cerveny, a scientist at the WMO. "Of course, maximum waves have been recorded up to 29 meters [95.1 feet]," Cerveny told Live Science, but the WMO began using averages in 2007 so that their records would be more accurate, he said.

The buoy that recorded the massive wave is part of the Marine Automatic Weather Stations, run by the U.K.'s national weather service, called the Met Office. This buoy, as well as others in the network, helps the WMO and its partners monitor the oceans, and complements measurements taken by satellites and ships.

"We need high-quality and extensive ocean records to help in our understanding of weather [and] ocean interactions," Zhang said. "Despite the huge strides in satellite technology, the sustained observations and data records from moored and drifting buoys and ships still play a major role in this respect."

He noted that wave height is defined as the distance from the crest of one wave to the trough (the lowest part) of the next wave.

The highest waves usually happen in the North Atlantic because wind-circulation patterns and atmospheric pressure in the winter lead to intense, extratropical storms called "bombs." That makes the region from the Canadian coast around Newfoundland to the south of Iceland and to the west of the United Kingdom a prime spot for these thunderous wave records.

"The new world record will be added to the official WMO archive of weather and climate extremes, which is being constantly updated and expanded thanks to continued improvements in instrumentation, technology and analysis," said Randall Cerveny, the joint rapporteur on world records of climate and weather extremes for the WMO. (A rapporteur is a person appointed by an organization to report on the proceedings of meetings. In the WMO case, the rapporteur keeps an official, unbiased list of world weather extremes.)

"Oceans cover some 70 percent of the world's surface," Cerveny said. "Ocean observations are therefore critical to understanding and forecasting our weather and climate.

The WMO also archives the world's highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, as well as hemispheric weather and climate extremes, the organization said in the statement.

Earlier this year, the WMO confirmed the longest reported distance for a lightning bolt (in Oklahoma) and the longest duration for a single lightning flash (in southern France). 

Original article on Live Science.

62-Foot Wave Off Iceland Smashes World Record

A monstrous swell in the North Atlantic that rose up as high as a six-story building is now the world's tallest wave measured by a buoy, according to the World Meteorological Organization (WMO).

The wave crashed down the morning of Feb. 4, 2013, in the watery expanse between Iceland and the United Kingdom, at approximately 59 degrees N, 11 degrees W. It occurred after a strong cold front passed through the area, producing winds of up to 50.4 mph (43.8 knots), the WMO reported.

The North Atlantic is a prime setting for smashing big-wave records. The previous buoy-measured record of 59.96 feet (18.275 m) also occurred in the North Atlantic, on Dec. 8, 2007, as did the tallest wave measured from a ship — a 95.03-foot-tall (29.05 m) swell on Feb. 8, 2000, the organization said. [See Photos of Monstrous Ocean Waves]

"This is the first time we have ever measured a wave of 19 meters. It is a remarkable record," Wenjian Zhang, the assistant secretary-general of the WMO, said in a statement. "It highlights the importance of meteorological and ocean observations and forecasts to ensure the safety of the global maritime industry and to protect the lives of crew and passengers on busy shipping lanes."

The WMO added that the new record isn't from one wave, but rather an average of 10 to 15 wave heights, which "is a more reliable measure of wave height than that of a single wave," said Randall Cerveny, a scientist at the WMO. "Of course, maximum waves have been recorded up to 29 meters [95.1 feet]," Cerveny told Live Science, but the WMO began using averages in 2007 so that their records would be more accurate, he said.

The buoy that recorded the massive wave is part of the Marine Automatic Weather Stations, run by the U.K.'s national weather service, called the Met Office. This buoy, as well as others in the network, helps the WMO and its partners monitor the oceans, and complements measurements taken by satellites and ships.

"We need high-quality and extensive ocean records to help in our understanding of weather [and] ocean interactions," Zhang said. "Despite the huge strides in satellite technology, the sustained observations and data records from moored and drifting buoys and ships still play a major role in this respect."

He noted that wave height is defined as the distance from the crest of one wave to the trough (the lowest part) of the next wave.

The highest waves usually happen in the North Atlantic because wind-circulation patterns and atmospheric pressure in the winter lead to intense, extratropical storms called "bombs." That makes the region from the Canadian coast around Newfoundland to the south of Iceland and to the west of the United Kingdom a prime spot for these thunderous wave records.

"The new world record will be added to the official WMO archive of weather and climate extremes, which is being constantly updated and expanded thanks to continued improvements in instrumentation, technology and analysis," said Randall Cerveny, the joint rapporteur on world records of climate and weather extremes for the WMO. (A rapporteur is a person appointed by an organization to report on the proceedings of meetings. In the WMO case, the rapporteur keeps an official, unbiased list of world weather extremes.)

"Oceans cover some 70 percent of the world's surface," Cerveny said. "Ocean observations are therefore critical to understanding and forecasting our weather and climate.

The WMO also archives the world's highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, as well as hemispheric weather and climate extremes, the organization said in the statement.

Earlier this year, the WMO confirmed the longest reported distance for a lightning bolt (in Oklahoma) and the longest duration for a single lightning flash (in southern France). 

Original article on Live Science.

Mystery Solved! Cause of London's 1952 'Killer Fog' Revealed

London may be known for its drizzly weather, but in 1952 the city's quintessential fog cover turned deadly, and no one knew why — until now.

For five days in December 1952, a fog that contained pollutants enveloped all of London. By the time the dense fog cover lifted, more than 150,000 people had been hospitalized and at least 4,000 people had died. Researchers now estimate that the total death count was likely more than 12,000 people, as well as thousands of animals. Despite its lethal nature, the exact cause and nature of the killer fog has largely remained a mystery. Recently, a team of researchers has determined the likely reasons for its formation.

Researchers have for a long time connected emissions from burning coal with the killer fog, but the specific chemical processes that led to the deadly mix of pollution and fog were not fully understood. To determine what turned the fog into a killer, an international team of scientists from China, the U.S. and the U.K. recreated the fog in a lab using results from laboratory experiments and atmospheric measurements from Beijing and Xi’an, two heavily polluted cities in China. [In Photos: World's Most Polluted Places]

Study lead author Renyi Zhang, an atmospheric scientist at Texas A&M University, said that sulfate was a big contributor to the deadly London fog. Sulfuric acid particles, which formed from the sulfur dioxide that was released from the burning of coal, were also a component of the fog. The question was, How did sulfur dioxide get turned into sulfuric acid?

"Our results showed that this process was facilitated by nitrogen dioxide, another co-product of coal burning, and occurred initially on natural fog," Zhang said in a statement. "Another key aspect in the conversion of sulfur dioxide to sulfate is that it produces acidic particles, which subsequently inhibits this process."

The natural fog contained larger particles, Zhang explained, with the smaller acidic particles evenly distributed throughout. When those fog particles evaporated, an acidic-haze was left covering the city.

The 1952 killer fog led to the creation of the Clean Air Act, which the British Parliament passed in 1956. Researchers still consider it the worst air pollution event in European history.

The air of cities in China, which is often heavily polluted, has a chemistry that's similar to the killer fog in London, Zhang and his colleagues found. China has battled air pollution for decades, and it is home to 16 of the world's 20 most polluted cities, according to the researchers. For instance, air pollution in Beijing often far exceeds the U.S. Environmental Protection Agency's acceptable air standards.

The researchers said that the main difference between China's smog and the killer London fog is that China's haze is made up of much smaller nanoparticles. Also, the formation of sulfate is only possible with ammonia, the scientists added.

"In China, sulfur dioxide is mainly emitted by power plants. Nitrogen dioxide is from power plants and automobiles, and ammonia comes from fertilizer use and automobiles," Zhang said. "Again, the right chemical processes have to interplay for the deadly haze to occur in China. Interestingly, while the London fog was highly acidic, contemporary Chinese haze is basically neutral."

A better understanding of air chemistry is key to developing effective regulatory actions in China, Zhang said.

"We think we have helped solve the 1952 London fog mystery and also have given China some ideas of how to improve its air quality," Zhang said. "Reduction in emissions for nitrogen oxides and ammonia is likely effective in disrupting this sulfate-formation process."

The research was published online Nov. 9 in the journal Proceedings of the National Academy of Sciences.

Original article on Live Science.