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Slide Show: 10 Important Atmospheric Science Experiments
From air, space, and deep in a forest, scientists air out climate models with lab and field work
Slide Show: 10 Important Atmospheric Science Experiments
THE PERFECT DATA STORM With some experiments, the goal is to get the best data possible. In some, it's just to survive in one piece. Joshua Wurman, head of the Center for Severe Weather Research Boulder, Colo., likes to be in the thick of it. With a roving lab that he calls the Doppler on Wheels (DOW), he has taken data from tornadoes, hurricanes, lightning storms and major forest fires. In 2008 he drove into Hurricane Gustave, and sampled from the eye of Hurricane Ike (as well as from Rita's in 2005). He has taken data from 121 tornadoes and studied the turbulence over the Alaska's capital, Juneau. The main challenge, he says, is not developing equipment that is high-tech enough, but rather low-tech enough. His gear needs to take a beating, so the heavier and simpler, the better. "I like dumb engineering," Wurman says, "It's very tempting in engineering to make fancy things with lots of bells and whistles. But in the real world when you go out on a dirt road in Kansas, it breaks." For his next round of tornado sampling, though, he has splurged and will be using a new radar system that takes six readings in quick succession (using multiple beams), rather than one. Like a camera that can take pictures six times faster, he hopes this will keep him from missing the things that happen in between readings
At some point, tornado researchers need to decide when to continue collecting valuable data and when to just make a run for it.
Herb Stein/Center for Severe Weather Research
DO PLANTS POLLUTE, TOO? When people talk about pollution, mostly they think of nasty stuff from giant smokestacks that kills nearby plants. What they don't know is that those plants are releasing the same chemicals. Allen Goldstein is on the cutting-edge of research into plant-released volatile organic compounds (VOCs). VOCs are a family of noxious chemicals associated with air pollution (think of solvents and paint thinners). They are also the compounds that make pine trees smell so fresh. Plants release millions of tons per year that quickly turn into aerosol haze (like the haze for which the Smokey Mountains are named). Although it's not technically pollution, no one knows how many of these chemicals are out there or exactly how they affect the atmosphere or climate. So Goldstein's team goes to California's Sierra Nevada mountains to hunt for new chemicals and try to guess how existing ones might be interacting. Using a number of techniques (including sealing off tree branches to tinker with surrounding air and temperature) they are also trying to understand how VOCs might change with global warming. One student even found a new chemical feeding the aerosols—the same chemical that makes fennel smell like licorice.
A view of the tower in Blodgett Forest that Goldstein's lab uses to sample volatile compounds put off by the trees.
Allen Goldstein University of California Berkeley
HUNGRY HUNGRY HIPPO Scientists have become very good at taking air samples from the ground and plugging them into global carbon dioxide models. What is missing from this picture is a comprehensive view of what is happening higher up. Enter HIPPO—a three-part pole-to-pole mission designed to fill in those gaps. Led by Harvard University researchers and the University Corporation for Atmospheric Research, the plan was to fly a specially outfitted former corporate jet from one pole of the planet to the other and back again, collecting samples all along the way. The first of the three flights finished in January and returned some surprising results. It found that carbon dioxide seems to migrate north, accumulating above the Arctic. Meanwhile, the Antarctic seems to collect more than its share of oxygen. Scientists say this may be a new kink in the global CO2 picture, or it may just be a seasonal shift. To find out which it is, the jet will fly two more identical flights at different times of the year.
The Arctic, as seen from HIPPO's converted corporate jet, called HIAPER.
University Corporation for Atmospheric Research
ON THE HUNT FOR BLACK CARBON Scientific experiments are designed to benefit science. But what's to stop them from benefiting humanity at the same time? This is the question posed by an ambitious new project headed by Veerabhadran Ramanathan at the Scripps Institute of Oceanography in San Diego. Ramanathan is an expert in "black carbon," one of the major components of soot and has tracked huge clouds of it over the Indian and Pacific oceans. Much of that carbon seems to come from the developing world, where poor families cook over open stoves with wood or charcoal. No one really knows, however, just how large a role these stoves play in black carbon emissions. So, in a perfect melding of science and philanthropy, Ramanathan wants to conduct a massive multimillion-dollar experiment whereby he replaces the stoves in 8,000 northern Indian households with low-tech, cleaner-burning stoves. Then, using tower and satellite-based sensors, he wants to monitor atmospheric changes and combine them with data taken from heat and particulate monitors mounted in the homes themselves. The results will not only tell scientists what role traditional cooking plays in climate change, they may help to lessen that role.
A woman in the Indian town of Amethi standing by a traditional stove and its fuel. The heavy smoke from the fire has blackened the wall around where she cooks and breathes.
Veerabhadran Ramanathan/Scripps Institute of Oceanography
MEASURING METHANE Carbon dioxide, as everybody knows, is the primary culprit in climate change. But many don't know that, pound for pound, methane is the more effective greenhouse gas. Recently, scientists have started looking at methane to understand just how it fits into the climate change picture. Unlike carbon dioxide, a great deal of methane may come from natural sources. The most troubling of these is melting tundra permafrost, because that will only increase as temperatures increase. With this in mind, teams of scientists from the National Oceanic & Atmospheric Administration (NOAA), the Russian Academy of Sciences and the University of Alaska Fairbanks have descended on the tiny Siberian town of Cherskii. A number of experiments there are helping round out the picture of Arctic methane emissions. One of the devices they are using is a new methane detector that can take readings in real-time. Scientists were so excited to get it out into the field that they attached it to a shed and dragged it out onto the tundra behind a retired Soviet tank. "This is a little shed that used to be used for smoking fish," says Ed Dlugokencky, a researchers with NOAA, "It's not generally heated, the power is a generator that is two kilometers [1.2 miles] away…. It's probably the most difficult conditions you can imagine to make measurements like this."
Getting the tower station out into the tundra proved harder than expected, even with a Soviet-era tank to drag it. Researchers had to just hope that nothing was damaged after one little accident.
IT'S LIKE WATCHING GASES MIX Many atmospheric mysteries could be solved if we could just see the interactions happening. Sadly, however, you can't just slice out a hefty piece of the atmosphere's lowest and densest layer, the troposphere, and lug it to a lab to watch a chemical reaction in action. The closest approximation is to inject two gases into a small cylinder, let them waft together past some artificial sunlight, and see what comes out the other side. In most labs, the process takes seconds, perhaps a couple minutes. A team at the University of California, Irvine, decided to up the ante. Over two years, they built a 30-foot (nine meter) chamber that looks more like a missile than a test tube and outfitted it with UV lamps. It wasn't easy. "There's all kinds of mixing and fluid dynamics issues," team leader Barbara Finlayson-Pitts says, "If you add something in the front end, you want it moving in a line down the flow tube. You don't want a bunch of it diffusing ahead or diffusing behind. You don't want it sitting in the center of the tube." The expanded size allows the scientists to watch gases mix for hours—more akin to the timescales and often tiny concentrations found in nature. Currently, the team is using the device (which still lacks a snappy name) to mix trace forest chemicals with common pollutants to see how urban pollution affects the gases given off by plants.
Looking more like a captured warhead than a piece of lab equipment, the flow tube at the University of California, Irvine, takes up several rooms.
Barbara Finlayson-Pitts/University of California, Irvine
THE ATMOSPHERE FROM SPACE What flies more than 400 miles (640 kilometers) above Earth and is better than a satellite? How about six satellites? That's the thinking behind the so-called A-Train (sometimes called the "Afternoon Constellation")—six satellites, each orbiting just minutes or even seconds behind the previous, taking varying snapshots of clouds and atmospheric gases." Think of it as a cloud researcher's version of a boy band: There's Aqua (he looks at evaporation and movement of water), CloudSat (he measures physical properties of clouds), CALIPSO (he measures aerosols, among other things), PARASOL (he sees microphysical properties), and Aura (the dreamy one in the back that looks at infrared radiation and ozone emissions). And like most rock bands, there was a death—the Orbiting Carbon Observatory (the shy boy who had the all-important task of monitoring atmospheric CO2 levels but crashed and burned after his February 2009 launch). Together they can observe details that none could parse individually. Recently, taking turns over South America, the group compiled observations indicating that polluted clouds rain less than clean ones. The next addition will be Glory, set to monitor the role of clouds and airborne particles in climate change after its launch slated for October.
Aura, the last satellite in the train, looks ahead over an imaginary set of train tracks at his fellows orbiting high over the Earth.
THE FACE OF THE EARTH Can you imagine what the world would look like if you took Earth's carbon dioxide levels from before the Industrial Revolution and doubled them? Actually, no one can. That's because no one knows exactly how carbon dioxide fits into all of Earth's processes. That's why scientists use Free-Air Carbon Enrichment (FACE) to essentially turn up the knob on ambient carbon dioxide and create an artificial atmosphere of the future. Aspen FACE in northern Wisconsin surrounds nine forest plots, each about the size of a baseball infield, with hoses that spray CO2 on the trees. By cranking up the CO2 to 560 parts per million (an optimistic guess for 2050 levels), they see how a mini ecosystem adapts to the change. But unlike other FACE sites, Aspen also turns up the amount of ozone (the major ingredient of smog) around the trees. Among other things, they are finding that CO2 boosts growth, ozone retards it, and pests seem to enjoy the futuristic mix.
A bird's-eye view of the Aspen FACE facility and its 12 rings.
David F. Karnosky
THE RIGHT STUFF Some experiments are done in the lab. Some are done in the field. Others, however, are happening right under our noses. Linnea Avallone, an associate professor at the University of Colorado Department of Atmospheric and Oceanic Sciences, sees an experiment in every rocket that's launched into the atmosphere. Scientists still don't know much about the stratosphere—the layer just above the one we inhabit. Yet every time a rocket sends something into space, it passes through the stratosphere and leaves a trail of chemical fuel exhaust. All that's missing is someone to watch it. So Avallone and her team attached sensors to a sleek fighter jet–like plane called a WB-57F, which is used by NASA to monitor shuttle launches and make sure nothing comes off that shouldn't. Then she asked the pilots, if it wasn't too much trouble, to please fly straight through the invisible wake of the rocket engines—at night. The pilots relished the challenge and what came out was the discovery of a new process whereby exhaust can erode stratospheric ozone. Avallone says even if the shuttle program ends, expect to see more of her devices somehow piggybacked on NASA flights.
NASA's maneuverable WB-57, the plane that follows the shuttle to look for problems. Now, thanks to Avallone's team it also samples stratospheric gases.
CAPTURE THAT CARBON To even make a dent in Earth''s phenomenal carbon dioxide budget surplus, scientists say humans need to begin thinking about capturing large amounts of carbon and burying it. Not hundreds of tons, not even thousands, but millions of tons of carbon dioxide per year. So where do we put it? The standard answer is in old oil and gas fields, which the U.S. Department of Energy estimates could hold around 90 billion tons of CO2 (just two years of global output). If, however, we could reliably hold CO2 in underground salt lakes, called saline aquifers, we could store 10 to 40 times more than that. With this in mind, researchers at the University of Calgary in Alberta teamed up with industry for the Wabamun Area CO2 Sequestration Project (WASP). David Keith, the project's principal investigator, says they are in the early phases of scouting an area in central Alberta to potentially store around a billion tons of carbon dioxide over the next 50 years. Unlike other projects on this scale, the site is not a former oil field, and although it is right next to some coal plants, it has never been mined (because the only thing down there is saltwater). If it works, industry would have a way to store carbon on a large-scale, and therefore affordably. "The scientific community really loves the idea of doing very finely instrumented, small-scale tests," says Keith, "but I don't think that will answer the questions we need to answer to move this forward at a large scale."
Master's student Chris Eisinger holds out cores of porous stone that have been drilled out of the potential sequestration site in Alberta. Behind him is a giant screen showing the geology of the site
Ken Benidtsen, University of Calgary