Why it snows so much in the frozen North

Dec 23, 2013 by Marcia Goodrich
Why it Snows so Much in the Frozen North
Scientists have long puzzled over the seemingly ceaseless drizzle of snow drifting down from arctic clouds, like these in the ocean off Norway's north coast. A team led by Michigan Tech's Raymond Shaw may have an answer. Credit: Thinkstock

(Phys.org) —When it doesn't show signs of stopping, most of us just mumble a few choice words and get out the snow shovel. Scientists, however, wonder where all that snow is coming from, particularly in pristine places like the Arctic. Raymond Shaw and his colleagues may have found an answer.

Here's the conundrum: Snow doesn't just materialize out of thin air. For those delicate, six-sided crystals of ice to form, they need a nucleus, a speck of dust, where water molecules can cling and order their structure as they freeze. Those ice-forming nuclei are relatively rare. Yet, over the Arctic, where the atmosphere is very clean and the ocean is covered with ice, sometimes it snows interminably. With bazillions of snowflakes crystalizing over dust specks and falling to Earth, why don't the clouds run out of nuclei? And why doesn't it quit snowing?

The same question applies to a lesser degree in places like Lake Superior, whose soggy clouds drop countless megatons of on the hapless residents of Minnesota, Wisconsin and Michigan.

"Within a few hours, you basically purge the atmosphere of all those particles," said Shaw, a physicist at Michigan Technological University. "So how can it snow for days on end?"

To answer the question, Shaw and his colleagues, including graduate student Fan Yang, set about developing a model to describe how ice crystals form, grow and fall, and they backed it up using data on arctic clouds, which are very well studied. They hoped that by characterizing just how snow comes into being, they would uncover clues to the puzzle.

What they discovered surprised them. As the number of increases, their mass soars by a power of 2.5. "Our first guess would have been that if you triple the number of crystals, you triple the mass," said Shaw. "It turns out to be a much stronger relationship than that." For example, if you triple the number of crystals, the mass goes up by a factor of 16. Simply put, the more crystals you have, the bigger they are.

Their model hinges on the idea that ice crystals are forming on atmospheric particles that were previously thought to be useless for making ice crystals. "The key assumption we made was that there's a hidden source of that's always there, but they are just really, really low efficiency," said Shaw. "The consensus in the research community has been that you need special pieces of dust to catalyze the ice. We thought, 'What if there was more stuff out there that would produce ice if you just wait long enough? Maybe when you put it in contact with a drop of water, it doesn't freeze immediately. But if you wait an hour, or two hours, it does. Our model assumes that the atmosphere is full of those really inefficient nuclei."

Those inefficient nuclei are behind those big crystals that show up during heavy snowfalls.

"The mass of an is related to its growth time," Shaw said. "The longer it's in the cloud, the bigger it will be." So, when there's an updraft that keeps crystals from falling, snowflakes that form on regular, snow-forming particles get larger and larger. During that time, many more snowflakes have a chance to form on weak nuclei.

Eventually, all the snow get too heavy for the updraft to support, and they tumble earthward. By then, they are huge, and there are lots of them. Not only is that born out in Shaw's model, it also appears to fit  with data gathered from arctic clouds.

They don't know what those weak nuclei are, or where they come from. But the scientists on Shaw's team are confident enough in their existence that they are looking for them in lab experiments.

"By assuming they are there, we got this mathematical prediction that fits with the experimental data," said Shaw. "So there's indirect evidence that these inefficient are there. This could be a solution to the mystery."

Explore further: The Arctic is especially sensitive to black carbon emissions from within the region

More information: Read the paper: www.arm.gov/science/highlights/R00504/pdf

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User comments : 12

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yoatmon
1 / 5 (5) Dec 23, 2013
Could the earth magnetic field lines eminating at the north and south pole have an unknown effect on the building of snow crystals?
cantdrive85
1 / 5 (6) Dec 23, 2013
Could the earth magnetic field lines eminating at the north and south pole have an unknown effect on the building of snow crystals?

The sun-earth connection is most direct at the poles, the particles may be space dust. Themis discovered these "giant magnetic ropes" which are birkeland currents and are more than capable of providing a steady stream of electrodynamically active nano space dust created by plasma processes on the sun.

http://science1.n..._themis/

http://arxiv.org/...2245.pdf
Mike_Massen
4 / 5 (4) Dec 24, 2013
Well its obvious why Antarctic is colder than Arctic & why there is more snow & ice changes between seasons, the hot air rises goes up North & the cold air falls & goes down South, its as plain as the length of the nose on a climate change deniers face (when faced with incontrovertible evidence they have significant difficulty addressing risk assessment issues given rise of CO2 over extremely short time frames (meh, so there) ;-)
Shootist
2.3 / 5 (3) Dec 24, 2013
Scientists have long puzzled over the seemingly ceaseless drizzle of snow drifting down from arctic


kidding, right?

frigid dry air goes south following jet stream. meets warm moist air rising north out of the Gulf due to motion of the Bermuda High. Result. Snow. Ice. Rain. Not necessarily in that order.
Mike_Massen
3.5 / 5 (4) Dec 26, 2013
My god woa ! Shootist exclaims with
Scientists have long puzzled over the seemingly ceaseless drizzle of snow drifting down from arctic
kidding, right?
frigid dry air goes south following jet stream. meets warm moist air rising north out of the Gulf due to motion of the Bermuda High. Result. Snow. Ice. Rain. Not necessarily in that order.
WoW, Have I misjudged you Shootist ?

It does seem as if you accept a complex issue inherent in human influenced climate change, is it too late to amend your hhrrrmmm AGW accepting 'comment' nah, too late ;-)
Whydening Gyre
4 / 5 (2) Dec 27, 2013
Sorry bout the 4 star, Mike. Was going for the "newest first" button...
Old Guy in Stanton
2.3 / 5 (3) Dec 29, 2013
Not trying to threadjack, but this seems as good a thread as any to ask a question. Without saying where I stand on the issue, what is the status of AGW Deniers on this forum? Are they banned? Tolerated? Encouraged? Read the FAQs and didn't see anything explicitly one way or the other. Curious minds want to know. Thanks, OGIS
Whydening Gyre
5 / 5 (3) Dec 29, 2013
Not trying to threadjack, but this seems as good a thread as any to ask a question. Without saying where I stand on the issue, what is the status of AGW Deniers on this forum? Are they banned? Tolerated? Encouraged? Read the FAQs and didn't see anything explicitly one way or the other. Curious minds want to know. Thanks, OGIS


Try getting thru the 500 some odd posts on the article about the Koch Bros. and company funding Denial - and you'll get a good idea.
Maggnus
2 / 5 (3) Dec 29, 2013
what is the status of AGW Deniers on this forum?
I suggest tolerated would be accurate. There is certainly no effort to stifle any debate with them, although frankly, but for a very few, I think they are allowed to hang around because their arguments are so ridiculously inept and conspiratal in nature that they give a good lesson on how not to debate actual science. And, often, they are funny as all get out! Follow some of the longer threads and typou can ferret out all kinds of logical fallacies, zombie arguments, and denialist and conspiracist agenda's. The whole gamut of how to not conduct yourself on a science site!
Lol I'm betting you're about to hear all about how awful I am now! I scoff at the dirty horse-trough waters!

cantdrive85
1 / 5 (2) Dec 29, 2013
Follow some of the longer threads and typou can ferret out all kinds of logical fallacies, zombie arguments, and denialist and conspiracist agenda's

LOL
http://phys.org/n...firstCmt
Mike_Massen
3 / 5 (2) Jan 01, 2014
In reply to Old Guy in Stanton,

AGW deniers can't seem to offer any sort of Science based response when asked a very simple basic question:-

Given the thermal properties of CO2 are well known *and* CO2 is increasing in the atmosphere as indicated by this site often used by AGW deniers in 'Cherry Pick' mode http://www.woodfo...rg/notes then why shouldn't there be overall temperature increases at all ?

In terms of details, always useful;

- Humans burn ~230,000 Litres of petrol/sec, releasing CO2, H2O & of course heat,
yet deniers offer no rationalisation as to why CO2 should not increase global temperatures ?

- H2O has easy path out of atmosphere as rain, snow, hail & mostly to oceans but, CO2 does not,
logic suggests CO2 is a key causal factor driving global warming.

AGW deniers often go down the political conspiracy route to 'take property' & redistribute wealth etc.

I wonder what real wealth the AGW deniers are most concerned about losing in such a conspiracy ?
Whydening Gyre
5 / 5 (1) Jan 03, 2014
"Why it snows so much in the frozen North"

Because it's the FROZEN North?

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