Starship Asterisk*

florid_snow, I read the abstract in the link, and do not agree, though I think the standard explanation for the formation of mammatus clouds may not be complete either. To me, it's clear that mammatus clouds are not formed just from the heating of the underside of anvil clouds. If that were the case, then most anvil clouds over warm dry land would grow them.

I have seen them in Florida several times, and Florida is usually quite humid, and seemed to be at the times. Most every time, they formed under the anvil of a severe storm. The main differences between the anvil of a severe storm and the anvil of an average storm, is its thickness, and the height of it. The thicker an anvil cloud is, the more precip (in the form of snow) there is, and the more precip there is, the more and stronger the downdrafts are. These downdrafts may indeed have to be above air that is drier than average. When the downdrafts hit the drier air, the snow sublimates and contributes moisture to the dry air, thus making the air around the downdraft lobe more buoyant, and causing it to rise around and between the lobes. Heat radiation from the ground may add to the buoyancy of the outsides of the lobes. In a house fire, you will get flames below the ceiling that look similar when "flashover" occurs (google flashover to see some pictures). These flames that look like mammatus clouds are caused by cooler and denser flammable vapors (smoke) falling down from the ceiling and then igniting on contact with oxygen and existing flame.

OK, I get the formation of the bubbles but why are they in such sharply defined lines?

geckzilla wrote:
ta152h0 wrote:
just imagine what our ancestors thought a few millenia ago upon seeing this and deciding which god was mad that day ?

And maybe, just maybe, one of them sat and pondered what really caused the clouds to do that.
And just what would someone have gotten from 'pondering', way back then?

invention of the wheel, so the ancient ponderer could follow them....I need an ice cold one
SW

[quote="geckzilla"][quote="ta152h0"]just imagine what our ancestors thought a few millenia ago upon seeing this and deciding which god was mad that day ?[/quote]

And maybe, just maybe, one of them sat and pondered what really caused the clouds to do that.[/quote]
And just what would someone have gotten from 'pondering', way back then?

[quote="ta152h0"]just imagine what our ancestors thought a few millenia ago upon seeing this and deciding which god was mad that day ?[/quote]

And maybe, just maybe, one of them sat and pondered what really caused the clouds to do that.

Another way mammatus cloud formation can occur is by "reverse-direction convection." This happens when convection in these clouds is so strong that it not only develops an overshooting top, but warm air travels to the underside of the anvil creating pockets of warm air, thus producing this odd formation.

just imagine what our ancestors thought a few millenia ago upon seeing this and deciding which god was mad that day ?

The first time I saw these i thought of Massive Posteriors floating in the sky. A heavenly BA if you will

The day after these clouds every facebook page from someone in Regina had pictures of these amazing clouds that covered the city in the evening, it was a beautiful surreal sight.

Never mind the breast jokes....Regina was also noted by Mick jagger as the city that rhymes with fun

Great shot Craig, nice work!

At first, I saw an interesting cloud formation of “bubbles”. But after reading the caption and everyone’s comments… all I see are a lot of breasts… there are two close together that are of particular interest… gee…thanks… I guess. I am supposed to work some today… now my mind is clouded with mammatus.

[quote="Strangerbarry"]Re: "Normal cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. "

Wouldn't this mean the TOPS should be flat ?[/quote]

As different parcels of clear air rise, they all cool at the same rate and reach the condensation temperature at the same level, and the cloud's base appears flat. Then, as different parcels of cloudy air rise (towards the top), their vertical velocity will change based on how much they mix with the environment. If a cloud is still warm enough to be rising, it will not have a flat top, but a buoyant bubbly looking top.

The parcels of cloudy air will eventually reach a level where they are no longer buoyant; you'd think they'd all stop there and be flat. But some may still have positive vertical velocity by that level and overshoot the top, bouncing around a bit before spreading out flat. You are probably familiar with flat top clouds, anvil clouds. That's cloudy air that has reached it's non-buoyancy level at a very specific temperature, with corresponds to a very specific height because the atmosphere is so spread out horizontally. Explaining the distribution of cloud top heights is the fundamental question a convection parameterization answers for a climate model.

To explain mammatus clouds (which almost always form on the underside of anvils) you must explain their bubbly buoyant appearance. The text under the APOD uses the old explanation, that bigger cloud particles settle in the lobes and are sinking. Another explanation is that as the anvil spreads over warm dry land it is heated by radiation from the ground, and develops a convective bubbly appearance. The mammatus lobes are just what's left behind as other sections of the anvil are gently heated and begin to rise up. This would also explain why mammatus rarely form when it is very humid at levels below the anvil (water vapor absorbs the ground's radiation, reducing what the anvil is exposed to). Since this theory explains more but is slightly simpler, it is more compelling.

Signed,
A grad student reading too many papers about this

http://journals.ametsoc.org/doi/abs/10.1175/2010JAS3513.1?journalCode=atsc

Re: "Normal cloud bottoms are flat. This is because moist warm air that rises and cools will condense into water droplets at a specific temperature, which usually corresponds to a very specific height. "

Wouldn't this mean the TOPS should be flat ?

Oh, come on, there's nothing wrong with showing [url=http://en.wikipedia.org/wiki/Breast]breasts[/url] or especially not [url=http://en.wikipedia.org/wiki/File:Breastfeeding_infant.jpg]an infant breastfeeding[/url], as long as it's on topic, which in that case it would be odd to randomly talk about breasts. Of course, you wouldn't want to look at the above two links if you were at work. It might alert the boss to the fact that you are messing around on Asterisk!

i'd be lost without my pockets! :D :wink:
[img2]http://upload.wikimedia.org/wikipedia/commons/thumb/9/9d/Jeans_pocket_back.jpg/220px-Jeans_pocket_back.jpg[/img2]

[quote="starsurfer"][quote="Ann"]

swelling mammatus clouds[/quote]
OMG! Is that even allowed here?! :D[/quote]
All part of our Regina Monologues.

[quote="Ann"]swelling mammatus clouds

Ann[/quote]
OMG! Is that even allowed here?! :D

At first sight, I thought clouds are going to fall down...not as single drops, more like fogg coming down...

This is a fascinating pic, makes me wonder how gases are doing on other planets, like Jupiter, what kind of clouds, gases they have and how it would look
watching Jupiter's sky from the inside...

Ah, mammatus clouds! :D They are named after "breasts", which they resemble. They make me want to post a picture of a woman nursing her baby, but I don't think that would be allowed! :wink:

Then again, these clouds are full of water - and soon after the picture was taken, the Earth was probably nursing these clouds, drinking water from them! How extremely lucky we are to have water falling from the sky, usually in suitable amounts.

Of course, if we hadn't had a precipation cycle with involving liquid water, we wouldn't have been the same kind of beings that we are now. Alternatively, we wouldn't have existed at all. Take your pick.

But these swelling mammatus clouds are a beautiful reminder of the fertility of planet Earth.

Ann

Thought it was bubble wrap for a moment...

:---[===]*

Mamma-mia, datsa soma spec-a-tactular Mammatus :!: :!:

[url=http://apod.nasa.gov/apod/ap121023.html][img]http://apod.nasa.gov/apod/calendar/S_121023.jpg[/img] [size=150]Mammatus Clouds Over Saskatchewan[/size][/url]

[b] Explanation: [/b] [url=http://www.newton.dep.anl.gov/askasci/wea00/wea00041.htm]Normal cloud bottoms are flat[/url]. This is because moist warm air that rises and cools will [url=http://www.weatherquestions.com/What_are_condensation_nuclei.htm]condense[/url] into water droplets at a specific temperature, which usually corresponds to a very specific height. As water [url=http://earthobservatory.nasa.gov/Library/GlobalClouds/]droplets grow[/url], an opaque cloud forms. Under some conditions, however, [url=http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/home.rxml]cloud[/url] pockets can develop that contain large droplets of water or ice that fall into clear air as they evaporate. Such [url=http://en.wikipedia.org/wiki/Pocket]pockets[/url] may occur in [url=http://en.wikipedia.org/wiki/Turbulence]turbulent[/url] air near a [url=http://apod.nasa.gov/apod/ap101130.html]thunderstorm[/url]. Resulting [url=http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/oth/mm.rxml]mammatus clouds[/url] can appear especially [url=http://www.youtube.com/watch?v=Mt0zXfEktuQ]dramatic[/url] if sunlit from the side. These [url=http://en.wikipedia.org/wiki/Mammatus_clouds]mammatus clouds[/url] were photographed over [url=http://en.wikipedia.org/wiki/Regina,_Saskatchewan]Regina, Saskatchewan[/url], [url=http://en.wikipedia.org/wiki/Canada]Canada[/url] during the past summer.

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