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Mobile Lab Set to Study Clouds' Influence on Weather and Climate

Clouds are important in understanding how the atmosphere behaves. They reflect sunlight back into space, trap heat and carry moisture, all of which can have contradictory impacts
Horizon Lines



Flickr/ARM Climate Research Facility

Some new cargo is officially sailing today between Los Angeles and Honolulu, part of an atmospheric research expedition to understand how clouds influence weather patterns around the world.

The 892-foot Spirit, a container ship owned by Horizon Lines, is now home to a Department of Energy mobile laboratory designed to study the atmosphere. It is the second time the department is conducting such an experiment in the hopes of getting better data on clouds to improve global climate models.

"This is going to be the longest study of its type that's ever been done," said Ernie Lewis, the principal investigator and an atmospheric scientist in the environmental sciences department at Brookhaven National Laboratory. The project, known as MAGIC, will run until September 2013, with collaborators across the country including Argonne National Laboratory and NASA's Jet Propulsion Laboratory.

The project's name reflects its history and the amalgamation of experiments now on the high seas. MAGIC stands for Marine ARM GPCI Investigation of Clouds. ARM stands for Atmospheric Radiation Measurement. GPCI stands for GCSS Pacific Cross-section Intercomparison. GCSS stands for GEWEX Clouds Systems Study. And GEWEX is the Global Energy and Water Cycle Experiment.

Basically, the instruments measure the atmosphere -- particularly clouds -- from the bottom up, tracking how they form and disperse. Using radars, spectrometers and laser detection systems crammed into the three 20-foot shipping containers that constitute the second ARM Mobile Facility (AMF2), the equipment will track black carbon, aerosols, cloud stacks, ozone, light transmission, wind speeds and temperatures. Two on-board technicians will also launch weather balloons and monitor more than 50 instruments. Lewis said the data could help modelers develop a better picture of the global climate.

Clouds are especially important in understanding how the atmosphere behaves. They reflect sunlight back into space, trap heat and carry moisture, all of which can have contradictory impacts. Varieties like puffy, cottony cumulus clouds; wavy stratocumulus clouds; and tall, thundering cumulonimbus clouds behave differently as well.

In this case, researchers are investigating low marine boundary layer clouds over the Pacific Ocean. "We don't have a good understanding about how clouds and white clouds form the way they do, especially in that region," Lewis said. "To get this understanding, we need more than just a global view; we need a very detailed measurement."

Getting 'closer to the action'
Joao Teixeira, a researcher at the Jet Propulsion Laboratory who worked on AMF2, explained that most of the existing global climate models do not have the resolution to interpret clouds. Many break the atmosphere into 100-kilometer-by-100-kilometer boxes, too large to reflect how clouds form.

"The fundamental question is really how do you represent the small-scale processes that you cannot explicitly model," he said, adding that clouds are a major source of uncertainty in climate projections.

As the global climate changes, the clouds may also subtly shift, creating different feedbacks and mechanisms in models. "You're not going to have a whole new type of cloud. They will be vaguely the same but occupy different regions," Teixeira said.

AMF2 will also help validate measurements from other sources, like satellites and aircraft. Teixeira said measurements from above clouds often have to use proxies to find out information like temperature and wind speed. Comparing these data with measurements from the sea upward could give scientists a better understanding of the variables at play.

Tracking these parameters at sea also helps fill another critical information void. Most atmospheric measuring stations are on land, but water covers two-thirds of the planet, where air circulation and moisture behave differently. MAGIC gives researchers a narrow but important window to the skies over the ocean that they can extrapolate to other parts of the world.

"This is allowing you to have much more local measurement, much closer to where the action is," Teixeira said.

'A deployment of opportunity'
But getting a seafaring lab to work on the waves without compromising measurements is a unique challenge. "We've had to adjust some of the baseline instrumentation," said Michael Ritsche, technical operations manager for AMF2, based at Argonne. He explained that scientists had to calibrate and adjust detectors to compensate for the boat's movements.

"A lot of sensors like to be straight, they like to be vertical," he said. To keep the hardware pointed the right way, researchers mounted some instruments on stabilized platforms while making software adjustments for others. The salty sea spray can degrade and corrode metals, which can wear out sensors, so technicians will have to keep a close eye on their performance.

Managing the logistics also required some ingenuity. Out on the high seas, if something breaks, it cannot be fixed until the Spirit returns to port, which is about every two weeks. In addition, the scientists have a narrow window of only two days to download their data and check their instruments while the ship loads up in Los Angeles.

"This is a cargo ship. We're just coming along for the ride," Ritsche said. "This is a deployment of opportunity. It moves back and forth whether we're on it or not."

Still, the arrangement offers some advantages. "For a fraction of the cost, we are able to do the same type of research you would be able to with an actual research vessel," said Nikki Hickmon, a meteorologist at Argonne.

Once the Spirit returns to port, researchers will have their first data batch. This mission's success could spur further sea-based climate studies to give scientists a better view into the planet's atmospheric future.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

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