Everyone see things in the clouds. People, animals, Christ on the cross, UFO’s, angels, and even schizophrenically imagined chemical attacks by contrails. You name it, somebody has seen it. So when I was prodded with a news item that said “new cloud type defined” I was thinking “uh oh, here we go again”. It is a lot like cyclomania, as humans tend to assign patterns to randomly ordered observations of nature. Looking for meanings in the clouds isn’t much different than looking for meanings in the alignments of the stars and planets.
From ChattahBox and The UK Telegraph:
(ChattahBox)—Meteorologists around the world have taken notice of a new storm cloud on the horizon, literally. And if they have their way the dark and choppy cloud will take its rightful place among its more famous cousins, cumulus, cumulus, cirrus and nimbus.
Cloud gazing Meteorologists first noticed the stormy and billowy formation floating over the Scottish Highlands and above Snowdonia, Wales. The unique gray storm cloud was also spotted over Australia, the cornfields of Iowa and high above the Arctic Sea off the coast of Greenland.
A group in England dedicated to cloud watching, the Cloud Appreciation Society, became quite excited when viewing numerous photos of the new storm cloud floating in the atmosphere.
The Cloud appreciators describe the cloud as “…a bit like looking at the surface of a choppy sea from below,” said Gavin Pretor-Pinney, founder of the Cloud Appreciation Society, and the first man to identify the new cloud.
The Royal Meteorological Society has named the new cloud, “Asperatus,” the Latin word for rough, since the cloud has the appearance of a rough, choppy ocean.
The Royal meteorologists are now attempting to have Asperatus officially recognized by the UN’s World Meteorological Organization in Geneva to have it included in the International Cloud Atlas.
If the meteorologists are successful, this would mark the first time a new cloud was officially recognized since 1953.
I have seen clouds like this, but did not see them as being a new classification. Thus a little trouble with the idea of making an entirely new classification for this cloud, a sub classification perhaps would be more appropriate, especially since this cloud does not appear to inhabit the middle and higher levels of the atmosphere.
Here are the existing classifications:
| Latin Root | Translation | Example | ||
| cumulus
stratus cirrus nimbus | heap
layer curl of hair rain | fair weather cumulus
altostratus cirrus cumulonimbus |
Classifications
High-Level Clouds
Cloud types include: cirrus and cirrostratus.
Mid-Level Clouds
Cloud types include: altocumulus, altostratus.
Low-Level Clouds
Cloud types include: nimbostratus and stratocumulus.
Clouds with Vertical Development
Cloud types include: fair weather cumulus and cumulonimbus.
Other Cloud Types
Cloud types include: contrails, billow clouds, mammatus, orographic and pileus clouds.
Source: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/home.rxml
So for “asperatus” I could see maybe “stratoasperatus” but not “altoasperatus” since there is no evidence of them at the high altitudes, and clouds at that level tend not to be rough edged.
I actually hope WMO doesn’t accept this ploy for attention by the Cloud Appreciation Society, if they do, it could open an avalanche of new cloud classification applications, we may see pitches of the most absurd kind.
For example, here’s another one from the Cloud Appreciation Society:
“Altostratus Obamus” perhaps?
People see all sorts of things in the sky, if this new one is accepted, the petitioning for WMO recognition of new cloud types would never end.
Another alarmist story about how AGW will cause worse Hurricanes and flooding due to 7 to 23 inch sea level rise in the next 100 years based on the IPCC.
http://www.khou.com/topstories/stories/khou090601_tnt_global-warming-hurricanes.3ab467cf.html
Take a valium before you read it. It’s going to raise your blood pressure.
Why not a post about the “New Age” creed or the “Green Agenda” ? to find out why “they” arrived at such preposterous idea of marketing “Global Warming” and why not another more intelligent and credible theory.
Glenn (18:21:26) :
It’s obvious why the RMS is playing “what figures can you see in the clouds”. From the article:
“Professor Paul Hardaker, the Chief Executive of the Royal Meteorological Society, said: “The process is a long and convoluted one to get through, but we believe there is a good case for this cloud to be added.
“There would probably need to be quite a lot of heat around to produce the energy needed to generate such dramatic cloud formations.
Well the new name suggests itself then:
Nimbyus Nostradamus
Look these “Asperatus Maunder Minimum”:
http://www.giurfa.com/venice.jpg
The undulation pattern in the clouds might be from “gravity waves” (that’s different from “gravitational waves,” mind you). As several commenters have said, it occurs in the lee of mountains. Gravity provides the restoring force, hence the name. If that’s what these are, I recall reading about this effect in clouds 10-15 years ago in Physics Today.
“”” Tim Hamilton (04:45:31) :
The undulation pattern in the clouds might be from “gravity waves” “””
Tim, ordinary deep ocean waves are “gravity” waves; typically wind powered, and as you state, the restoring force on a displaced particle is gravitational, and the wave propagation is non dispersive, so the waves are simple harmonic motion, and all frequency components have the same wave velocity.
In water, you also have another restoring force, that is surface tension; which acts to try and minimise the surface area. But whereas the restoring force in gravity waves is proportional to displacement; (which is the differential equation definition of simple harmonic motion); the surface tension restoring force is absolutely independent of particle displacement, and depends only on the surface tension of water (Newtons per metre).
So surface tension waves are anything but SHM, and the are highly dispersive; so the short wavelength higher frequencies travel faster than the longer wavelenght lower frequencies.
Out in deep ocean waters; the surface tension is totally swamped by the gravity , so deep ocean waves travel non disp[ersively at the same velocity independent of wavelength.
But as the water shallows near shores, and beaches, the power in the gravity waves is reduced while the surface tension remains constant, so the surface tension waves start to dominate, and the higher frequencies run ahead of the lower frequencies, so the wave shape changes from sinusoidal for the SHM gravity waves to a sawtooth waveform, with the water poiling up at the front edge of the wave. Well eventually the high frequencies go right over the cliff, and at a given water depth, depending on the height of the waves, the wave leading edge collapses in the mess that beach bums and surfers travel the world to find.
The atmosphere doesn’t really have anything comparable to surface tension, so we never see those aparatus waves breaking on an upside down beach.
You do need air flow over the lip of the organ pipe (hills) to get the waves started; which is why you don’t see these over the flat midwestern cornfields; and notice that the waveforms are pretty nice symmetrical sinusoids, althoguht they are travelling in several directions and interfering with each other. The interference pattern is going to depend on the ridge line of the hills, and how many indivdual sources it creates; via passes, and peaks.
George
“”” Paul Coppin (08:45:55) :
Digging a little deeper around the web, it would appear that this cloud form is already defined as stratus or altostratus undulatus, undulatus referring to the wavy bottom, and that the cited examples of “asperatus” at CAS are just good examples of the form. You might make a case for some examples being “mammatus undulatus”, depending on their genesis.
At any rate, another word doesn’t seem necessary or desirable, and they are certainly not “new storm clouds”. “””
Paul, I suspect that the only difference between these aparatus clouds, and lenticular clouds, is one of persistence.
With lenticulars, they seem to form right over the generating peak, as a result of being forced up in altitude; till condensation occurs; but they re-evaporate, once the waveform dips lower, thus cutting off the lenticle.
George
George E. Smith–
Thanks a lot for the review of water waves. I knew that they had some real deviations from simple harmonic motion, but I hadn’t heard the reason explained so clearly before. The equations for water wave speed as a function of depth is rather complex. I’ve been trying to assign a student project to design a diffraction grating that would work with water waves, as well as a “lens” that would use a variable water depth to focus the wave. But it’s hard to get a usable effect in the ripple tank without going extremely shallow (~< 1/16"). Next time I try it, I'll have a good explanation of why it works at all, though.
“”” Tim Hamilton (08:52:00) : “””
Tim; One of my Second year Physics Lecturers; who taught the Sound and accoustics part of Physics; had a waves on water fetish.
It didn’t matter what subject he got started on; he could eventually bring it around to waves on water; whcih he loved.
Speaking of diffraction gratings; have you ever considered the idea, that a wave pattern on the surface of the water, is itself an accoustic diffraction grating.
It came to me once, while standing out on the Florida Keys Tarpon flats (on a boat) fly rod in hand, and waiting for a tide change that was calculated to bring the thundering herd of critters right past our stake out spot.
There was an almost imperceptible faint breeze blowing that created a slight wave pattern on the water, which was good for the tarpon to not be so skittish; but not so much wave as to slap against the hull, creating a noise which would blow them off our location.
Yet it wasn’t quiet; my guide commented about the interminable; but faint rushing sound in our ears; with no apparent source. So during a pregnant pause in the action; he asked me what the hell the noise was all about. That gave me an idea that set me bobbing up and down to get my ear as close to the water as possible (flats boats are very low freeboard).
Sure enough; as I changed my ear height, the sound changed its character.
Then I realized that the winds from far away were in fact generating a lot of noise all around us, but it was only audible for the sounds coming from a region close enough to us (but all around us) to be audible.
The somewhat chaotic surface wave pattern was acting as a surface diffraction grating of somewhat undefined but not totally random spacing, that was diffracting the essentially white noise into a frequency spectrum that was distributed roughly in verticaql angle from that apparent audible source radius.
So my up and down bobbing was simply scanning the sound spectrum, and listening to the frequency shift.
Needless to say; my guide (The Scientific American Recipient) was bloody impressed; and of course he made full use of his lecture episode to bamboozle his fellow guides at the bar apres fish. Darn sure we won ourselves a few free drinks at some of those bar meetings.
Yes waves are fun visual things for students; if you can turn just one on with them, it is worth the effort. You can show them interference and diffraction all in a shallow tank with simple apparatus; and hopefully get some surf bums to pay attention more often.
George
PS if you have some apparatus you can use with soap films to demonstrate the surface tension, and its independence of displacement, unlike a balloon skin. Like a couple of parallel wires with one movable end, so you can demonstrate that the work done is simply T x the change in area of the film.
Remember soap films are double sided so it is 2T x delta (a).
My grey matter is a little rusty so I don’t have a mental figure for the order of magnitude of T for modern soap films.
My wife and I saw this same formation over northern Dallas County just a couple of weeks ago. Most unusual — I had never seen clouds like that before.
I just saw this where I live in Crestline, California, 5000 feet above see level. I had never heard of these clouds before and had certainly never seen them. I stood there watching them for a long, long time trying to figure out what they were because they were unidentifiable. Then I took a whole role of film. (:o)) Anyway, I’m glad to know these DO have a name, but now I wish that I understood what caused them to form.