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Masterpiece of the Sky
12.01.05
 

Who Are NASA's Earth Explorers?

The elementary school student wondering how El Niño will affect tomorrow's weather. The scientist studying connections between ozone and climate change. And the farmer using satellite pictures to keep track of crops. All of these people are Earth Explorers -- they are all curious about the Earth system. This series will introduce you to NASA Earth Explorers, young and old, with many backgrounds and interests.


A scientist looking at clouds may think about their influence on weather and climate. An artist is more likely to view clouds as fluffy forms of white and gray that filter light and cast shadows.

Graeme Stephens sees both the scientific and artistic sides of clouds.

Stephens is the head scientist for NASA's CloudSat mission. CloudSat is a satellite that will observe clouds in greater detail than ever before. It is scheduled to launch no earlier than February. Stephens is also an artist. He has painted a series of pictures showing a variety of cloud types.

Graeme Stephens stands in front of a painting of large white clouds in a pale blue sky
Earth's atmosphere has long been a place where science and art converge. Eric Sloane's book from 1941 -- "Clouds, Air and Wind" -- is a perfect example. Sloane was an artist. But his book was made into a weather guide for military pilots. Poets and philosophers have also been known to ponder clouds and the sky above.

Image to right: Artist and scientist Graeme Stephens stands with some of his artwork. Credit: William Cotton
"Art and science have much in common. And much has been written about the common threads between both," Stephens said. "Both, after all, are different expressions of the natural world around us."

Clouds have appeared in paintings and drawings since ancient times. Artists gave little attention to the science of clouds, however, until the 1800s. Englishmen Joseph Turner and John Constable were among the first to do so. They painted clouds with accurate scientific detail. They may have taken their cues from Luke Howard.

Howard was an amateur meteorologist. He invented a system for classifying and naming clouds. He announced his system in 1802. It described the appearance of clouds with names like "cumulus" and "cirrus." These are Latin words meaning "heap" and "curl of hair," respectively. The system may have helped artists to draw clouds that were more realistic.

These days, scientists are the ones looking to paint their own picture of clouds. They have many questions about clouds. Do they keep Earth cool by blocking sunlight? Or do they warm Earth by trapping radiation from the surface? What percentage of clouds produce precipitation? If Earth were warmer, would there be more of certain kinds of clouds and fewer of others?

"Our ability to forecast clouds and rainfall from clouds is poor," Stephens said.

A painting of wispy clouds in a red, orange and blue sky
CloudSat will try to answer scientists' questions about clouds. Its main instrument is the Cloud Profiling Radar, or CPR. The CPR is a very powerful radar. It is so strong that it can see past the outer surface of clouds to what's going on inside of them. CloudSat will be the first satellite able to see clouds and precipitation at the same time.

Image to left: Cirrus at Sunset, by Graeme Stephens.
Credit: Chris Chrissotimos


The path of CloudSat's orbit will be close to that of several other Earth observing satellites. These satellites are known as the "A-Train." They are designed to work together to better understand Earth's climate. The data they collect will be combined and used in models that predict weather and climate change.

If all goes as planned, CloudSat will bring scientists one step closer to creating a more detailed portrait of clouds and the Earth's water cycle. It may be one that even Stephens the artist can be proud of.

Stephens says he appreciates the role of all clouds in science and art. High or low, thick or thin, he says they all have an impact on our climate and a place in his artwork. Most of all, he says he enjoys "the way clouds of all types interact with light." And he says he enjoys the way they form "the wonderful skyscapes we see as we look upwards."

See previous Earth Explorers articles:
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Related Resources
CloudSat
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CloudSat Art Gallery
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Earth as Art
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Dan Stillman, Institute for Global Environmental Strategies