Published in the Antarctic Sun
A small team of researchers is painting the white-on-white landscape of Antarctica in bright colors. The Support Office for Aerogeophysical Research, headed by Don Blankenship of the University of Texas at Austin, is looking at the continent in ways many scientists have only imagined.
SOAR is a consortium of researchers looking at how ice and rock interact in Antarctica. Their maps are in full color, showing different types of rocks and land formations, often over a mile under the ice sheet.
The researchers fly in a Twin Otter airplane over swaths of area larger than the state of Maine, to look at the ice-flow systems in key regions of the continent.
“We’re trying to figure out how geology influenced the formation of the ice sheets,” Blankenship said.
The airplane is crammed with electronics, so many that it takes two to three weeks to configure properly.
That’s after the plane’s structure was so radically modified that it required its own certification from Canada’s Ministry of Transport before Kenn Borek Air was allowed to fly it.
“The airplane was put together to do both geology and glaciology projects at once,” Blankenship said. In addition to the internal instrumentation, it has antennas hanging off the wings.
The electronics are all sophisticated sensors, measuring the plane’s height above the ice, using ice-penetrating radar to look at the rock beneath the ice, and also measuring the strength of the
gravity and magnetic pull of the rocks.
The gravity of the rocks, when separated from the influence of the Earth’s pull, shows how dense the rock is, giving clues to its composition. When that is combined with information about the
rock’s magnetic properties, the type of rock can be identified quite accurately.
Putting all this information together into a meaningful picture, Blankenship said, requires an additional layer of sophisticated equipment and calculation.
The airplane has several GPS units onboard, which measure the position of the plane to within four inches.
With that data, and the results from the instruments, Blankenship and his team create incredibly accurate maps of the ice and the surface beneath the ice sheets covering Antarctica.
“We’re good to within 10 centimeters,” Blankenship said.
They can find sediments, holes, changes in ice-sheet layering, and other phenomena. The SOAR team helps teams like ITASE choose routes for traverses, sites for ice-coring, and helps predict how what they find relates to other locations around the continent.
Their radar also lets them see significant layers in the ice sheet.
“It’s essentially virtual ice coring,” Blankenship said. The next actual deepcore site in West Antarctica will be chosen by the SOAR team, in collaboration with the ITASE researchers.
This season they made several excursions, one completing work they have been preparing for since 1992.
The plane and equipment flew routes over the transition from the Ross Sea to the Transantarctic Mountains, across the mountains to the Wilkes Basin and all the way to Aurora Highlands.
This cross-section of an area of the continent about which little is known geophysically was very important.
“We can get a really good handle on the evolution of the whole area,” Blankenship said.
The planning and organization resulted in use of several locations for this research and other work this season: McMurdo, Dome C, Mid C, Byrd and Siple Dome camps were all bases for SOAR flights.
For eight years the project has been underway to help explain why the Transantarctic Mountains are where they are. But once it’s all set, things move quickly.
“It took, what, 15 days to do,” Blankenship said. Good flying weather and few equipment difficulties were part of the success, as was increased computing power.
After a four-hour flight, the plane and equipment need about 90 minutes to refuel and recalibrate instruments. During that time, the researchers can take a provisional look at their data and get a sense of how reliable it is. Even just a few years ago, researchers needed more than five hours to do the same task.
“The quality of the data we get is really outstanding for the remoteness of the environment,” Blankenship said.
Sunday, February 6, 2000
Sunday, January 30, 2000
Pinsetting for dollars
Published in the Antarctic Sun
Housed in the basement of McMurdo’s Building 63 are two bowling lanes, one of a few remaining manually-set alleys in the world. The exact number is difficult to know, because they are so small and so rare.
The lanes were the site of last week’s bowling tournament final match, won by the Freshies, with the help of the people behind the pins.
Several McMurdo residents are pinsetters in their spare time, earning minimum wage and tips from bowlers.
It’s a rough job, involving constant bending and lifting in a confined space, moving speedily so as not to delay the bowlers, and also avoiding the 10- to 16-pound balls which hurtle down the lanes.
There aren’t all that many pinsetters today. In earlier days of bowling, fallen pins were collected by hand and re-set in place individually, often by young people, called “pin boys.”
At the end of World War II, there was a shortage of willing pin boys. Technology offered another solution, automated pinsetters. These were often cheaper to run, since one or two people could service numerous lanes at once.
“It’s very rare to find people who manually set the pins anymore,” Jim Dressel, editor of Bowler’s Journal International, said in a phone interview.
The machines themselves are also of interest.
“They’re antiques and they’re very valuable,” said spokeswoman Jackie Twa of Brunswick, the corporation which made the pinsetting trays used at McMurdo’s lanes.
Despite the lack of replacement parts, “you could sell them for a lot of money and buy a new center,” Twa said.
Dressel was surprised to learn of the existence of McMurdo’s artifact.
He recalled that in the 1940s and 1950s there were a number of bowling alleys installed in military bases around the world.
But the automated setters used by most bowling centers nowadays were first introduced in 1945 by AML, Dressel said. Brunswick started making them in 1950, he said.
The manual pinsetters in Building 63 carry the following information on the manufacturer’s label: “Style B-10,Brunswick-Balke-Collender.” The machines are serial numbers 1023 and 1028.
The company changed its name from Brunswick-Balke-Collender to Brunswick Corporation on April 18, 1960, according to Linda Haschke, a marketing representative for Brunswick.
Housed in the basement of McMurdo’s Building 63 are two bowling lanes, one of a few remaining manually-set alleys in the world. The exact number is difficult to know, because they are so small and so rare.
The lanes were the site of last week’s bowling tournament final match, won by the Freshies, with the help of the people behind the pins.
Several McMurdo residents are pinsetters in their spare time, earning minimum wage and tips from bowlers.
It’s a rough job, involving constant bending and lifting in a confined space, moving speedily so as not to delay the bowlers, and also avoiding the 10- to 16-pound balls which hurtle down the lanes.
There aren’t all that many pinsetters today. In earlier days of bowling, fallen pins were collected by hand and re-set in place individually, often by young people, called “pin boys.”
At the end of World War II, there was a shortage of willing pin boys. Technology offered another solution, automated pinsetters. These were often cheaper to run, since one or two people could service numerous lanes at once.
“It’s very rare to find people who manually set the pins anymore,” Jim Dressel, editor of Bowler’s Journal International, said in a phone interview.
The machines themselves are also of interest.
“They’re antiques and they’re very valuable,” said spokeswoman Jackie Twa of Brunswick, the corporation which made the pinsetting trays used at McMurdo’s lanes.
Despite the lack of replacement parts, “you could sell them for a lot of money and buy a new center,” Twa said.
Dressel was surprised to learn of the existence of McMurdo’s artifact.
He recalled that in the 1940s and 1950s there were a number of bowling alleys installed in military bases around the world.
But the automated setters used by most bowling centers nowadays were first introduced in 1945 by AML, Dressel said. Brunswick started making them in 1950, he said.
The manual pinsetters in Building 63 carry the following information on the manufacturer’s label: “Style B-10,Brunswick-Balke-Collender.” The machines are serial numbers 1023 and 1028.
The company changed its name from Brunswick-Balke-Collender to Brunswick Corporation on April 18, 1960, according to Linda Haschke, a marketing representative for Brunswick.
Sunday, January 23, 2000
It's a bird, it's a plane, it's a Hammerhead!
Published in the Antarctic Sun
It was a windy day out over the sea ice.
Coast Guard Lt. Tom McDevitt, the pilot, and flight mechanic Mark Henley were checking out sea ice conditions and “waving the flag” at the tourist ships in McMurdo Sound.
The pair made an efficient team. Henley’s suggestions were quietly worded questions, like “How much fuel are you leaving for the return trip?”
McDevitt answered, “400 pounds,” but later revised his plan, noting Henley’s implicit suggestion that the wind would be against them on the trip home.
The men are part of a 14-person Coast Guard helicopter crew temporarily stationed in McMurdo. Normally based either in Mobile, Alabama, or on one of the Coast Guard’s icebreakers, the team is now flying their two aircraft from a pad near the Chalet.
The crew, who call themselves the “Hammerheads,” but whose name is officially Aviation Detachment 146, started preparing for this trip in September. They did a lot of work on the helicopters, to be sure they’d be in top flying condition.
In October, the team flew to Seattle to meet up with the Polar Star for its cruise south. On the journey to Antarctica, they passed through areas of the Pacific Ocean that don’t normally get visits from the Coast Guard.
The helicopters flew off the icebreaker at various times to inspect ships in U.S. territorial waters, or to identify vessels suspected of smuggling drugs or illegal immigrants. Those tasks are major parts of the Coast Guard’s job, and even on a trip in international waters, information-gathering
helps U.S.-based crews enforce the law more effectively.
“We go to spots where most of our Coast Guard units don’t get to go,” said unit leader Lt. Cmdr. Rich Jackson.
As well, the ship and helicopters were always on call for rescue missions, had there been vessels in trouble nearby.
The trip to Antarctica and back takes six months. Jackson has planned for 300 hours of flying during that period, and expects to use it all. Some of it was spent on the way down, and some will be spent on the way back.
But most of the flying happens around Ross Island.
The helicopter crews are doing all kinds of work, from remote weather station maintenance to morale flights to the ice edge.
Most of their work involves support of the Polar Star, doing reconnaissance of ice conditions before the ship begins breaking ice, or ferrying people and equipment between the ship and the land.
“It’s probably the most demanding flying that we do in the Coast Guard,” Jackson said. The weather conditions and logistics make it much more difficult than flying from a ground station in the States. Not only do the helicopters have to carry skis on many missions over ice, but the crews need extra survival gear. Fuel-use margins are also stricter here, where weather can ground flights for long periods.
The ship can help, by positioning itself at a midway point in a long route, so the helicopters have somewhere to land if the weather turns ugly.
But even landing on the icebreaker can be very difficult: The ship’s hull is rounded for better icebreaking, but that means it rolls more in the waves than would a vessel with a sharper keel.
“We fly all over the world and sit there a while,” said rescue swimmer Steve Lurati, who has a brand of laconic sarcasm similar to the crew members. In a way, he’s right.
Jackson pointed out that Lt. Scott Craig, the engineering officer, much prefers scheduled maintenance to fixing broken equipment. So the mechanics work hard on regular preventive work and mostly avoid repairing parts on short notice.
Jackson also said this is the most motivated crew he’s worked with on the Ice, which helps because, as with everything in Antarctica, nothing goes exactly as planned.
“It’s never the same game twice,” he said.
The crew will be in McMurdo until the icebreaker departs with the Greenwave for the return journey to the U.S. The helicopters will fly off the breaker in San Francisco in April, and head back to Alabama.
It was a windy day out over the sea ice.
Coast Guard Lt. Tom McDevitt, the pilot, and flight mechanic Mark Henley were checking out sea ice conditions and “waving the flag” at the tourist ships in McMurdo Sound.
The pair made an efficient team. Henley’s suggestions were quietly worded questions, like “How much fuel are you leaving for the return trip?”
McDevitt answered, “400 pounds,” but later revised his plan, noting Henley’s implicit suggestion that the wind would be against them on the trip home.
The men are part of a 14-person Coast Guard helicopter crew temporarily stationed in McMurdo. Normally based either in Mobile, Alabama, or on one of the Coast Guard’s icebreakers, the team is now flying their two aircraft from a pad near the Chalet.
The crew, who call themselves the “Hammerheads,” but whose name is officially Aviation Detachment 146, started preparing for this trip in September. They did a lot of work on the helicopters, to be sure they’d be in top flying condition.
In October, the team flew to Seattle to meet up with the Polar Star for its cruise south. On the journey to Antarctica, they passed through areas of the Pacific Ocean that don’t normally get visits from the Coast Guard.
The helicopters flew off the icebreaker at various times to inspect ships in U.S. territorial waters, or to identify vessels suspected of smuggling drugs or illegal immigrants. Those tasks are major parts of the Coast Guard’s job, and even on a trip in international waters, information-gathering
helps U.S.-based crews enforce the law more effectively.
“We go to spots where most of our Coast Guard units don’t get to go,” said unit leader Lt. Cmdr. Rich Jackson.
As well, the ship and helicopters were always on call for rescue missions, had there been vessels in trouble nearby.
The trip to Antarctica and back takes six months. Jackson has planned for 300 hours of flying during that period, and expects to use it all. Some of it was spent on the way down, and some will be spent on the way back.
But most of the flying happens around Ross Island.
The helicopter crews are doing all kinds of work, from remote weather station maintenance to morale flights to the ice edge.
Most of their work involves support of the Polar Star, doing reconnaissance of ice conditions before the ship begins breaking ice, or ferrying people and equipment between the ship and the land.
“It’s probably the most demanding flying that we do in the Coast Guard,” Jackson said. The weather conditions and logistics make it much more difficult than flying from a ground station in the States. Not only do the helicopters have to carry skis on many missions over ice, but the crews need extra survival gear. Fuel-use margins are also stricter here, where weather can ground flights for long periods.
The ship can help, by positioning itself at a midway point in a long route, so the helicopters have somewhere to land if the weather turns ugly.
But even landing on the icebreaker can be very difficult: The ship’s hull is rounded for better icebreaking, but that means it rolls more in the waves than would a vessel with a sharper keel.
“We fly all over the world and sit there a while,” said rescue swimmer Steve Lurati, who has a brand of laconic sarcasm similar to the crew members. In a way, he’s right.
Jackson pointed out that Lt. Scott Craig, the engineering officer, much prefers scheduled maintenance to fixing broken equipment. So the mechanics work hard on regular preventive work and mostly avoid repairing parts on short notice.
Jackson also said this is the most motivated crew he’s worked with on the Ice, which helps because, as with everything in Antarctica, nothing goes exactly as planned.
“It’s never the same game twice,” he said.
The crew will be in McMurdo until the icebreaker departs with the Greenwave for the return journey to the U.S. The helicopters will fly off the breaker in San Francisco in April, and head back to Alabama.
Sunday, January 16, 2000
Out of Africa: A polar researcher
Published in the Antarctic Sun
Outside an elevated building near the South Pole, an Egyptian flag flaps in the polar wind. It belongs to Ashraf El Dakrouri, a laser scientist at the Aerophysical Research Observatory at South Pole Station.
El Dakrouri is the first Egyptian at the South Pole. For that matter, he pointed out, he is the first
person from either an Arab or a Muslim nation to go to the South Pole.
It’s a long way from Cairo to 90 degrees south, and El Dakrouri plans to winter at the pole as part of his research on the temperature of the mesosphere. He’s never done anything quite like this before.
“I don’t know what will happen,” El Dakrouri said. But he is in good spirits and is looking forward to the challenge. The experience may be even more difficult for him than for most pole winterovers.
El Dakrouri was married only a year and a half ago. He and his wife have a 6-month-old son in Cairo. They live with her family, and with his also nearby, there is plenty of help available.
“She lives with a lot of people, not like me,” El Dakrouri said.
He asked his wife about the possibility of his coming to the South Pole. She was initially reluctant, he said, but she eventually agreed, on the condition that he call every week. He does, using the phone facilities available each weekend.
Being away from family is tough, El Dakrouri said. But being able to do this sort of work, and being a pioneer for African Antarctic research, are important, too, he said.
It has been especially difficult to be away from home recently, during the Muslim holy month of Ramadan. It is a time of fasting and then feasting, usually with family. El Dakrouri is alone this Ramadan.
“The Egyptian people prefer to spend Ramadan in Egypt,” he said. “Next year I will spend Ramadan in Egypt.”
The year after that, he things he might come back to Antarctica the following year.
Ramadan has been strange for El Dakrouri, too, since eating is forbidden between sunrise and sunset. In a land with 24-hour daylight, that doesn’t quite work.
He knew he would have to deal with this, and asked religious leaders in Egypt what to do. They told him he could use the time of sunrise and sunset in the nearest country, so El Dakrouri is using New Zealand.
The fast is longer here, because of the higher latitude of New Zealand. In Egypt, he said, the time between sunrise and sunset is usually 12 to 15 hours, but here it is nearly 18.
“I try to sleep,” El Dakrouri said of how he spends his fasting time.
The galley staff at the station accommodate his unusual mealtimes, and help him avoid pork, a forbidden food for Muslims. They sometimes make a separate portion for him so it’s hot when he comes in to eat around 8 p.m.
Ramadan recently ended. Instead of the traditional celebration marking the end of the month, El Dakrouri did something a bit different.
“I try to make something fun for my feast,” he said. He headed to McMurdo for a couple of days to telephone his friends and family in Egypt.
He will return to Egypt at the beginning of next summer, to report back to the National Institute of Laser Science in Cairo, where he is a researcher, and to return to his teaching duties at Cairo University.
He feels some pressure now, though. Not only is his work new research, but he wants to become a better instructor as a result of his time here.
“I must take something higher to teach the students afterward,” El Dakrouri said. “A lot of students have a lot of ideas.”
He wants to encourage them to follow their dreams. He also hopes to make a good impression on the U.S. program and on his fellow researchers. He believes he is a representative of scientists from Egypt, Africa, and the Arab and Muslim worlds, who may one day work in Antarctica too.
“If you are the first person to so something, you want to do it very well,” El Dakrouri said. “I am a beginning. I hope a lot of people come after that.”
Outside an elevated building near the South Pole, an Egyptian flag flaps in the polar wind. It belongs to Ashraf El Dakrouri, a laser scientist at the Aerophysical Research Observatory at South Pole Station.
El Dakrouri is the first Egyptian at the South Pole. For that matter, he pointed out, he is the first
person from either an Arab or a Muslim nation to go to the South Pole.
It’s a long way from Cairo to 90 degrees south, and El Dakrouri plans to winter at the pole as part of his research on the temperature of the mesosphere. He’s never done anything quite like this before.
“I don’t know what will happen,” El Dakrouri said. But he is in good spirits and is looking forward to the challenge. The experience may be even more difficult for him than for most pole winterovers.
El Dakrouri was married only a year and a half ago. He and his wife have a 6-month-old son in Cairo. They live with her family, and with his also nearby, there is plenty of help available.
“She lives with a lot of people, not like me,” El Dakrouri said.
He asked his wife about the possibility of his coming to the South Pole. She was initially reluctant, he said, but she eventually agreed, on the condition that he call every week. He does, using the phone facilities available each weekend.
Being away from family is tough, El Dakrouri said. But being able to do this sort of work, and being a pioneer for African Antarctic research, are important, too, he said.
It has been especially difficult to be away from home recently, during the Muslim holy month of Ramadan. It is a time of fasting and then feasting, usually with family. El Dakrouri is alone this Ramadan.
“The Egyptian people prefer to spend Ramadan in Egypt,” he said. “Next year I will spend Ramadan in Egypt.”
The year after that, he things he might come back to Antarctica the following year.
Ramadan has been strange for El Dakrouri, too, since eating is forbidden between sunrise and sunset. In a land with 24-hour daylight, that doesn’t quite work.
He knew he would have to deal with this, and asked religious leaders in Egypt what to do. They told him he could use the time of sunrise and sunset in the nearest country, so El Dakrouri is using New Zealand.
The fast is longer here, because of the higher latitude of New Zealand. In Egypt, he said, the time between sunrise and sunset is usually 12 to 15 hours, but here it is nearly 18.
“I try to sleep,” El Dakrouri said of how he spends his fasting time.
The galley staff at the station accommodate his unusual mealtimes, and help him avoid pork, a forbidden food for Muslims. They sometimes make a separate portion for him so it’s hot when he comes in to eat around 8 p.m.
Ramadan recently ended. Instead of the traditional celebration marking the end of the month, El Dakrouri did something a bit different.
“I try to make something fun for my feast,” he said. He headed to McMurdo for a couple of days to telephone his friends and family in Egypt.
He will return to Egypt at the beginning of next summer, to report back to the National Institute of Laser Science in Cairo, where he is a researcher, and to return to his teaching duties at Cairo University.
He feels some pressure now, though. Not only is his work new research, but he wants to become a better instructor as a result of his time here.
“I must take something higher to teach the students afterward,” El Dakrouri said. “A lot of students have a lot of ideas.”
He wants to encourage them to follow their dreams. He also hopes to make a good impression on the U.S. program and on his fellow researchers. He believes he is a representative of scientists from Egypt, Africa, and the Arab and Muslim worlds, who may one day work in Antarctica too.
“If you are the first person to so something, you want to do it very well,” El Dakrouri said. “I am a beginning. I hope a lot of people come after that.”
A SPARCLE in their eyes
Published in the Antarctic Sun
Scientists who study gases mostly confine them to flasks in laboratories. Not Stephen Warren and Von P. Walden, atmospheric researchers from the University of Washington in Seattle. They are studying the air out on the polar plateau.
Away from the sterile, controlled environments of indoor research facilities, Warren and Walden have created their own work site right next to the Clean Air Sector. The project is called SPARCLE, the South Pole Atmospheric Radiation and Cloud Lidar Experiment.
“We’re studying processes important for climate,” Warren said. In 1985, Warren began examining how sunlight reflecting off snow affects the energy budget of Antarctica. An significant reason for the extreme cold of Antarctica is that snow reflects 83 percent of the incoming solar energy. Warren also looked at the sizes and shapes of the snow crystals themselves to learn why snow reflects sunlight the way it does.
Walden studied the other half of the energy budget, measuring the amount of infrared energy emitted by the different gases in the air, as well as by clouds. He found that even the small amount of water vapor over the plateau was responsible for two-thirds of the natural greenhouse effect here, and carbon dioxide was responsible for most of the rest.
Now they are combining their efforts in a two-pronged attack on a tough problem.
“The most important greenhouse gas, worldwide, is water vapor,” Warren said. But nobody has accurately measured how much infrared energy it is capable of absorbing at low temperatures.
This information is vital for predictions of climate change not just in Antarctica but around the world.
And conditions on the ground at the South Pole, with temperatures dropping to minus 120 F, are similar to those at high altitude, in the upper troposphere, elsewhere in the world.
Learning more about the interactions between water vapor and infrared energy helps make climate-change models more accurate. While many causes contribute to climate change,
Warren said, they come back to one place.
“They either start with radiation or involve radiation,” he said.
The team, including graduate student Penny Rowe and research meteorologist Richard Brandt,
has devised two different ways to look at water vapor.
One is using the flat expanse of the polar plateau to provide a long path of uniform air. They have an instrument that reports how much infrared energy is absorbed by water vapor in the air. But it can be reconfigured to measure how much infrared energy is emitted by the atmosphere.
Water vapor’s absorption, Walden said, is weak in parts of the infrared spectrum. So to measure it accurately requires a lot of water vapor in the air. At high temperatures, it’s easy to get lots of water vapor in a small chamber in a laboratory. But such high-temperature measurements
may not be applicable to the cold upper troposphere. At low temperatures, the only way to get sufficient water vapor is with a long distance, more than half a mile, of air. Because the plateau is featureless, the air moving across it is usually fairly uniform in terms of wind speed and direction, humidity and temperature.
The other way the team is measuring the characteristics of water vapor is with a tethered balloon. They can send different instruments up with the balloon, to more than a mile high,
and photograph ice crystals and measure humidity and temperature. Most of the water vapor in the atmosphere is in the lowest mile of air.
The tethered balloon also allows the team to take sustained measurements at fixed altitudes, which is uncommon. Usually this type of research is done from freely rising balloons or from
airplanes, which move quickly through clouds and also may alter the cloud properties.
Their observations are compared with existing models of the atmosphere and its characteristics. In collaboration with other climate modelers, the team’s new data can be incorporated into improved concepts of the climate.
The information is also useful for interpreting data from satellites and other remote-sensing devices. The devices can record observations, but to interpret that information requires a
knowledge of the processes involved, including how gases absorb radiation.
But Warren and Walden can’t observe everything at once. To complete their descriptions of atmospheric conditions, they collaborate with NASA, NOAA and local weather observers.
This summer’s research is largely a testing phase. Much of the real work will happen next summer and over the following winter of 2001. Two members of the group will winter at the
South Pole to conduct the research, which uses existing tools in new ways.
One of the instruments was originally designed to measure pollutants coming out of factory smokestacks. Now it’s in use measuring water vapor in Antarctic air.
“We’re using new technology to increase our understanding of the Antarctic continent to make better predictions of climate for this region,” said Walden.
Scientists who study gases mostly confine them to flasks in laboratories. Not Stephen Warren and Von P. Walden, atmospheric researchers from the University of Washington in Seattle. They are studying the air out on the polar plateau.
Away from the sterile, controlled environments of indoor research facilities, Warren and Walden have created their own work site right next to the Clean Air Sector. The project is called SPARCLE, the South Pole Atmospheric Radiation and Cloud Lidar Experiment.
“We’re studying processes important for climate,” Warren said. In 1985, Warren began examining how sunlight reflecting off snow affects the energy budget of Antarctica. An significant reason for the extreme cold of Antarctica is that snow reflects 83 percent of the incoming solar energy. Warren also looked at the sizes and shapes of the snow crystals themselves to learn why snow reflects sunlight the way it does.
Walden studied the other half of the energy budget, measuring the amount of infrared energy emitted by the different gases in the air, as well as by clouds. He found that even the small amount of water vapor over the plateau was responsible for two-thirds of the natural greenhouse effect here, and carbon dioxide was responsible for most of the rest.
Now they are combining their efforts in a two-pronged attack on a tough problem.
“The most important greenhouse gas, worldwide, is water vapor,” Warren said. But nobody has accurately measured how much infrared energy it is capable of absorbing at low temperatures.
This information is vital for predictions of climate change not just in Antarctica but around the world.
And conditions on the ground at the South Pole, with temperatures dropping to minus 120 F, are similar to those at high altitude, in the upper troposphere, elsewhere in the world.
Learning more about the interactions between water vapor and infrared energy helps make climate-change models more accurate. While many causes contribute to climate change,
Warren said, they come back to one place.
“They either start with radiation or involve radiation,” he said.
The team, including graduate student Penny Rowe and research meteorologist Richard Brandt,
has devised two different ways to look at water vapor.
One is using the flat expanse of the polar plateau to provide a long path of uniform air. They have an instrument that reports how much infrared energy is absorbed by water vapor in the air. But it can be reconfigured to measure how much infrared energy is emitted by the atmosphere.
Water vapor’s absorption, Walden said, is weak in parts of the infrared spectrum. So to measure it accurately requires a lot of water vapor in the air. At high temperatures, it’s easy to get lots of water vapor in a small chamber in a laboratory. But such high-temperature measurements
may not be applicable to the cold upper troposphere. At low temperatures, the only way to get sufficient water vapor is with a long distance, more than half a mile, of air. Because the plateau is featureless, the air moving across it is usually fairly uniform in terms of wind speed and direction, humidity and temperature.
The other way the team is measuring the characteristics of water vapor is with a tethered balloon. They can send different instruments up with the balloon, to more than a mile high,
and photograph ice crystals and measure humidity and temperature. Most of the water vapor in the atmosphere is in the lowest mile of air.
The tethered balloon also allows the team to take sustained measurements at fixed altitudes, which is uncommon. Usually this type of research is done from freely rising balloons or from
airplanes, which move quickly through clouds and also may alter the cloud properties.
Their observations are compared with existing models of the atmosphere and its characteristics. In collaboration with other climate modelers, the team’s new data can be incorporated into improved concepts of the climate.
The information is also useful for interpreting data from satellites and other remote-sensing devices. The devices can record observations, but to interpret that information requires a
knowledge of the processes involved, including how gases absorb radiation.
But Warren and Walden can’t observe everything at once. To complete their descriptions of atmospheric conditions, they collaborate with NASA, NOAA and local weather observers.
This summer’s research is largely a testing phase. Much of the real work will happen next summer and over the following winter of 2001. Two members of the group will winter at the
South Pole to conduct the research, which uses existing tools in new ways.
One of the instruments was originally designed to measure pollutants coming out of factory smokestacks. Now it’s in use measuring water vapor in Antarctic air.
“We’re using new technology to increase our understanding of the Antarctic continent to make better predictions of climate for this region,” said Walden.
Subscribe to:
Posts (Atom)