Please Answer

[quasigeostrophy]

This isn't a meme, but neither is it homework. It is related peripherally to my forthcoming Ph.D. work.

What about winter precipitation (freezing rain, sleet, snow), especially but not necessarily related to climate change, do you wish we (or even just you) knew more?

Comments

[rfrench.livejournal.com]

Aircraft icing prediction!

[quasigeostrophy.livejournal.com]

I figured you'd say that. :-) There have already been plenty of recent studies of that for which papers are just starting to come out. In fact, my advisor just got a couple published.

[gremlin44.livejournal.com]

Here's a question Kevin had for us yesterday--why is snow in the air "clear" but snow piled up on the ground white?

[quasigeostrophy.livejournal.com]

That one I can already answer: The crystal shapes of snowflakes scatter light as light passes through. Single, spaced apart flakes scatter the light away pretty rapidly, keeping the crystal clear. A collected pile of millions of flakes scatters light around so much that all the colors are scattered to the point where it sends them all back to you in enough intensity to be white light. If it scattered any colors more than any other, it would look colored (which is why the sky is blue). :-)

[sweet-tea79.livejournal.com]

Why does freezing rain suck so bad? And why are we so unprepared for it? This may be beyond your scope.

[quasigeostrophy.livejournal.com]

It sucks because the ground is colder than the air below cloud base, so it freezes on contact. Aspects of this are what I think I want to work on, actually. :-)

[beverlysyarncrazy.blogspot.com (from livejournal.com)]

Why doesn't the most frozen type of precipitation, hail, fall during the winter?

[quasigeostrophy.livejournal.com]

I would theorize that, because the temperature difference between cloud base and cloud top is lower in the winter (colder down here, but as cold up there), updrafts aren't as strong (strong thunderstorms aren't as prevalent in winter). It's those updrafts that toss the ice up through the cloud over and over and give it a chance to grow as a hailstone. In winter, the little ice crystals just fall right out.

[phinnia.livejournal.com]

hm.
how does 'lake effect snow' differ from 'regular' snow?

[quasigeostrophy.livejournal.com]

As in, is the snow actually different in composition, etc.? That might be worth checking into.

[brian1789.livejournal.com]

Processes behind high-velocity (>50kph) blown freezing fog? I run into these occasionally in the Arctic, and they're bizarre and unpleasant. Zero visibility, buffeting winds and ice skins on everything... have seen more of these on land at 75N in the past couple of years, as the nearby ocean pack ice has receded rapidly with warming.

[quasigeostrophy.livejournal.com]

I would theorize the winds are more fierce up there due in part to lack of surface friction slowing them down, and maybe (especially since the ice pack has receded with warming) somewhat due to an increased temperature gradient coming off the sea surface. Beyond that, adding the ice fog, it's an interesting issue that I may have to look into down the road. No one where I'm studying currently is an Arctic weather expert, though (no local advisement), so it may need to wait until I'm at least a postdoc.

[gows.livejournal.com]

Why on earth changing weather makes joints/old injuries/broken bones ache. I've asked my orthopedic surgeon a couple of times and no one seems to know for sure. What, specifically, happens, both in a weather context and a physiological context and how they work together. (Not sure if that's entirely close enough, but I figured it ought to count.)

[adularia.livejournal.com]

I always thought that was due to atmospheric pressure changes. Do pressure changes in airplane cabins have the same effect?

[quasigeostrophy.livejournal.com]

I think that will take more of a medically-related study than a specific meteorological one, but as far as I can tell it's related to pressure changes and the effect on fluids in the body. I know my sinuses are a powerful barometer of their own. :-)

[djinnthespazz.livejournal.com]

Mine's not really related to your question either.

What is the drive behind El Nino/ La Nina.

And since I'm asking be unaswerables...
How do these aspects change with global warming.

[kightp.livejournal.com]

Ooh - I can help with that one! Here's a nifty little publication on that very subject the program I work for put out in '97:

.pdf version with nifty illustrations.
HMTL version, without.

[kightp.livejournal.com]

Out here in Western Oregon, I've noticed that clear fall/winter nights almost invariably mean foggy mornings, while it's rarely foggy the morning after an overcast night.

Why is that?

[lightning-rose.livejournal.com]

Maybe a variation on Tule Fog?

http://en.wikipedia.org/wiki/Tule_fog

[lightning-rose.livejournal.com]

I'd like to know more about Mie scattering.

http://lightning-rose.livejournal.com/119868.html

[quasigeostrophy.livejournal.com]

So would I. ;-) It's certainly making my current work annoying. Rayleigh scattering is assumed for radar data, but I'm running into drops that are pushing into the Mie scattering regime and making my calculations suck.

not helping

[geekchick]

Why do otherwise-rational adults become complete freakin' idiots behind the wheel as soon as a single snowflake hits the ground anywhere within a 20-mile radius? ;)

Re: not helping

[quasigeostrophy.livejournal.com]

If I could answer that one, I probably wouldn't need the Ph.D. I want. ;-)

[hobbitblue.livejournal.com]

(phinnia pointed folks here & I hope you're taking dumb questions too :))

Often in winter you'll hear people say "Its too cold to snow," and often that's right, we end up with a heavy frost instead and very cold temperatures, and snow arrives when things warm up by a few degrees. Buts its much colder at the Poles, and it snows there, so what makes the difference? (I'm in Britain, if that's relevant to the answer at all :) )

[quasigeostrophy.livejournal.com]

As it gets colder, it takes less water vapor for the air to be saturated, but what people usually refer to with the phrase should be "the air is too stable to snow" - there's not enough of a temperature difference between the surface and aloft for the air to rise and create ice particle aggregates big enough to fall as snowflakes. At the poles, the air saturates readily even at the colder temperatures because of the easy available water (the Arctic ocean in the north, or existing snow/ice packs in the south).

[karenthecroccy.livejournal.com]

Buffalo, NY has the bestest weather EVER, right? :)

What's the difference between graupel, sleet and freezing rain? I mean, it's all crap, right?

[anmorata.livejournal.com]

I think you and I are on the same wavelength. :) Heheh.

[anmorata.livejournal.com]

What's the difference between sleet and hail? Is there? I've always thought that sleet was some in-between thing between hail and freezing rain, but I'm not really certain.

[quasigeostrophy.livejournal.com]

Sleet is just frozen supercooled raindrops that freeze on their way down through cloud and fall quickly, so they haven't made a lot of trips through cloud to get layered. Hail gets those layers by being thrown around through a storm cloud and collecting smaller droplets that freeze to the hailstone.

[dandelion-diva.livejournal.com]

Oh yes, absolutely.

[dandelion-diva.livejournal.com]

I'm a dork and misread. I thought you were asking if I wanted to know more, not what I wanted to know more about.

Is it cloudier in the fall/winter or does it just seem so because there are fewer daylight hours?

[sistercoyote.livejournal.com]

The problem with my question is that I suspect it already has been answered:

What is it about snowflakes in particular that leads to their twelve (? I think it's twelve)-sidedness? Ice crystals aren't naturally dodecahedral, are they?

[quasigeostrophy.livejournal.com]

Funny you should ask about what are called "ice crystal habits" considering a major paper classifying them came from someone who is where you are (and it's one of my favorite papers). :-) The shape of the water molecule, with the two hydrogens hanging off the oxygen atom at the angles they do, and then where the "leftover" pair of electrons on the oxygen atom sits, all contribute to the generally hexagonal shape of ice crystals. There are variations, of course (dendrites, plates, columns, needles, etc.), but you'll find a hexagon somewhere in all of them. The difference between the habits has been found to be temperature dependent. As for why that is, I think that still remains unknown.

[floating09.livejournal.com]

Well how about this, there are soooo many virga detection algorithms for liquid precip. but I have found only one for frozen precipitation. Given that most cold places are also fairly dry this presents a slight problem. Come up with a snow virga detection algorithm then give it to me to test lol lol lol ;)


ok ok then answer this ... find a better method for getting the snow to liquid ratio.

[quasigeostrophy.livejournal.com]

Heh. Actually your second suggestion is something I am considering investigating as part of my Ph.D. work. :-)