Camera Craniums

General Category => General Discussion => Topic started by: Graham on June 03, 2010, 12:59:36 PM

Title: Meteorologists?
Post by: Graham on June 03, 2010, 12:59:36 PM
  Can anyone out there explain the odd cloud effect in the right of this pic?
  We were on Kinder Scout which is large plateau of peat bog in the Peak District and it was very hot (still is!).

(http://cameracraniums.com/gallery/albums/userpics/normal_web_DSC3103.jpg)

                              Graham.   :)
Title: Re: Meteorologists?
Post by: picsfor on June 03, 2010, 01:01:12 PM
I'm going with a vapour trail of a passenger jet some time after it has flown on...
Title: Re: Meteorologists?
Post by: Graham on June 03, 2010, 01:05:52 PM
  Hells teeth Andrew, that was quick!
  I thought that, it apears to have parted the sky to reveal the clouds beyond.
  I also have a pet theory about thermals rising of the peat. :-\
                Graham.
Title: Re: Meteorologists?
Post by: hevans on June 03, 2010, 01:06:11 PM
Was the cloud pattern somewhat matching the top of the plateau? If so, then it'd result from hot dry air rising from the plateau and shoving the other (lower) clouds aside. I'm guessing that the clouds on the furthest right are at higher altitudes?.
Title: Re: Meteorologists?
Post by: Graham on June 03, 2010, 01:12:28 PM
  Jeez! Is'nt anyone at work today?
  Yes, that's kind of what I was thinking, it seemed so well defined as to be unnatural though.
  We met some Japanese chaps later on and they had also photographed it. (Great bunch of folks they were too.)
                            Graham. :)
Title: Re: Meteorologists?
Post by: Malcolm1938 on June 03, 2010, 02:22:37 PM
I'm no expert but it looks like something to do with the jetstream to me.
Title: Re: Meteorologists?
Post by: Malcolm1938 on June 04, 2010, 07:50:43 AM
(http://www.cloudman.com/look/wisps2.jpg)
This is from Google images - you can see why I think the jet stream may be involved - Google Jet Stream cloud formations to see other examples.

Title: Re: Meteorologists?
Post by: Graham on June 16, 2010, 05:53:09 AM
   Follow up:
                 On a whim last night at 10.30 I sent the picture to the Met Office. By 5.30 this morning I had this reply.

     The formation is caused by a delicate process. The cloud is a thin sheet of Altocumulus at an estimated height of 18000 ft, and it was most likely, originally, one solid sheet of supercooled cloud droplets. Supercooled droplets are well below freezing (i.e. -10C to -18C) but remain in liquid form, unfrozen, usually because the air is so clean and ice has nothing to freeze onto (ie. like frost on a clean window selectively forms on scratches or dirt).
 
If a disturbance occurs within the cloud, such as a plane going through it (adding microscopic particles into the air), this can kick-start the process of freezing the particles. As they freeze, they form into small ice crystals or tiny snow-flakes, and then fall out of the atmosphere. The cloud is then no longer there. It then becomes a progressive process, as one ice crystal forms, it absorbs the moisture of the surrounding supercooled droptlets and dries the air out. The result is the cloud will slowly dissapear from the point at which the freezing process first started.
 
It can also be caused by descending air from aloft, drying out the cloud, and causing the droplets to evaporate.
 
This cloud formation is more popularly known as a "Hole-Punch cloud", which are widely photographed and on the internet.
Title: Re: Meteorologists?
Post by: picsfor on June 16, 2010, 08:19:21 AM
   Follow up:
                 On a whim last night at 10.30 I sent the picture to the Met Office. By 5.30 this morning I had this reply.

If a disturbance occurs within the cloud, such as a plane going through it (adding microscopic particles into the air), this can kick-start the process of freezing the particles. 
It can also be caused by descending air from aloft, drying out the cloud, and causing the droplets to evaporate.
 
This cloud formation is more popularly known as a "Hole-Punch cloud", which are widely photographed and on the internet.


oh well, i was partly right - a passenger did get a mention! Interesting explanation though - thanks for posting.
Title: Re: Meteorologists?
Post by: hevans on June 16, 2010, 09:02:23 PM
Amusing, and a link to a report on the effect that was released today:

http://blogs.discovermagazine.com/80beats/2010/06/16/scientists-accidentally-confirm-that-jets-can-punch-holes-in-clouds/