Snow science: Crystal clues to climate change, watersheds
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Capturing snowflakes isn't as easy as sticking out your tongue.
At least not when you're trying to capture them for scientific study. This involves isolating the tiniest of crystals. They are isolated on a metal card. It is printed with grid lines. And then you must quickly place them under a microscope. Then they are photographed.
"They are very tiny and they are close to the melting point." That's according to Marco Tedesco. He works at Columbia University. "So as soon as they fall, they will melt."
Tedesco recently led a team of three researchers. They trudged through the snowy hills of New York's Catskill Mountains. They took cameras. They took brushes. They took shovels. They took a drone. And they took a spectrometer with them. They collected the most fine-grained details about freshly fallen snowflakes. And they noted how snowflakes evolve once they settle to the ground.
That data could be used to provide clues to the changing climate. It could also validate the satellite models used for weather predictions. And it could provide additional information on the snow that falls into New York's City's upstate watershed. It flows into reservoirs. And then it fills the faucets of some 9 million people.
"We're talking about sub-millimeter objects." That's what Tedesco said as he stood in shin-deep snow. "Once they get together, they have the power, really, to shape our planet."
This is the pilot stage of the "X-Snow" project. Organizers hope the project will involve dozens of volunteers. They will be collecting snowflake samples next winter. The specimens Tedesco spied under his microscope on a recent snowy day were varied. They displayed more rounded edges and irregularities than the classic crystalline forms. This is characteristic of flakes formed up high in warmer air.
Pictures and video from the drone will be used to create a three-dimensional model of the snow's surface. Patrick Alexander is a postdoctoral researcher. He trudged though the snow with a wand. It was attached to a backpack spectrometer. It measures how much sunlight the snow on the ground is reflecting. This a factor in determining how fast it will melt. Later, Alexander got down on his belly in the field. He did this to take infrared pictures of the snow's layers and its grain size.
"There are a lot of things that happen that we can't see with our eyes," said Tedesco. He is a snow and ice scientist. He works at Columbia's Lamont-Doherty Earth Observatory. "When snow melts and re-freezes, the grains get bigger. And as the grains get bigger the snow absorbs more solar radiation."
Tedesco grew up in southern Italy near Naples. He never even saw snow until he was 6 years old. But as a scientist, he has logged time studying ice sheets in Greenland and Antarctica. And he has studied snow hydrology in the Rockies and the Dolomites. He said snow in the Eastern U.S. has its own character. It tends to be moister than powdery snow. Powdery snow falls in higher elevations in the West.
Tedesco hopes that a cadre of committed volunteers in the Catskills and the New York City area can take snowflake and snow depth samples next winter. Volunteers won't need an expensive backpack spectrometer. He recommends some low-cost tools. These include a $17 magnifying lens. It clips onto their phone. He also recommends using a ruler. A GPS application is helpful. And a print-out version of the postcard-sized metal card he uses to examine fresh snowflakes.
Enlisting volunteers to take snowflake photos is novel. It is also potentially useful. That's according to Noah Molotch. He is director of The Center for Water, Earth Science and Technology. That't at the University of Colorado, Boulder. Molotch is not involved in the project. He said the pictures will give information about atmospheric conditions. It could be useful in the study of climate change.
"Snowflakes are among the most beautiful things in nature," he said. "And the more we can do to document that and get people interested and excited about that, I think is great."