Nacreous Cloud picture from 30/11

Thread View: uk.sci.weather

8 messages

[T] Back to Threads [V] Tree View [G] Group Articles

8 total messages Started by M Holmes Tue, 07 Dec 1999 00:00

#114

Author: M Holmes
Date: Tue, 07 Dec 1999 00:00

3 lines
913 bytes

I was sent this one taken from the Western General Hospital, Edinburgh:

www.ed.ac.uk/~erss01/cloud.htm

Re: Nacreous Cloud picture from 30/11

#110

Author: B Kemp
Date: Wed, 08 Dec 1999 00:00

1 lines
675 bytes

OK OK, what is nacreous cloud anyway?

Re: Nacreous Cloud picture from 30/11

#111

Author: Les Crossan
Date: Wed, 08 Dec 1999 00:00

15 lines
1413 bytes


B Kemp wrote:

> OK OK, what is nacreous cloud anyway?

In a word, it's ABOVE the tropopause in the stratosphere - the word
nacreous comes from the brilliant iridescence it has. Most often seen in
conjunction with deep low pressure systems - I was chasing the cold
front of this system (looking for funnels and tornadoes) in the Borders
when I saw this rare event.

There's believed to be a link with this cloud and ozone depletion(????)

Les

Re: Nacreous Cloud picture from 30/11

#107

Author: Les Crossan
Date: Thu, 09 Dec 1999 00:00

16 lines
1487 bytes


Rainer Thonnes wrote:

> In article <384ECD03.D2AF8B6F@virgin.net>,
>  Les Crossan <les.crossan@virgin.net> writes:
> >
> >There's believed to be a link with this cloud and ozone depletion(????)
>
> Someone showed me a map the other day of ozone levels for 30th Nov,
> and the "hole" was centred, guess where?  Right over Edinburgh!

Ah. Shouldn't I be wearing sunscreen and sunglasses  - or a radiation suit
- then??

How long did this hole last??

Re: Nacreous Cloud picture from 30/11

#108

Author: John Hall
Date: Thu, 09 Dec 1999 00:00

31 lines
2147 bytes

In article <38500CBD.EA0981C3@virgin.net>,
 Les Crossan <les.crossan@virgin.net> writes:
>
>
>Rainer Thonnes wrote:
>
>> In article <384ECD03.D2AF8B6F@virgin.net>,
>>  Les Crossan <les.crossan@virgin.net> writes:
>> >
>> >There's believed to be a link with this cloud and ozone depletion(????)
>>
>> Someone showed me a map the other day of ozone levels for 30th Nov,
>> and the "hole" was centred, guess where?  Right over Edinburgh!
>
>Ah. Shouldn't I be wearing sunscreen and sunglasses  - or a radiation suit
>- then??
>
>How long did this hole last??
>
>
The fortunate thing about ozone "holes" is that the mechanism is such
that, AIUI, they can only occur in winter. Even with the hole, the
amount of dangerous solar radiation you will receive in Edinburgh at
this time of year, when at midday the sun will be no more than about 15
degrees above the horizon, is I imagine likely to be considerably less
than you would get there at mid-summer with a full ozone layer.
-- 
John Hall
            "Three o'clock is always too late or too early
             for anything you want to do."
                                           Jean-Paul Sartre (1905-1980)

Re: Nacreous Cloud picture from 30/11

#112

Author: Martin Brown
Date: Thu, 09 Dec 1999 00:00

23 lines
1756 bytes

Les Crossan wrote:

> B Kemp wrote:
>
> > OK OK, what is nacreous cloud anyway?
>
> In a word, it's ABOVE the tropopause in the stratosphere - the word
> nacreous comes from the brilliant iridescence it has. Most often seen in
> conjunction with deep low pressure systems - I was chasing the cold
> front of this system (looking for funnels and tornadoes) in the Borders
> when I saw this rare event.
>
> There's believed to be a link with this cloud and ozone depletion(????)

That or the conditions where the clouds can form are right for acceleration
of the ozone depleting reactions. The real time plot over Uccle, Belgium
shows the effect of the recent event.

    http://www.meteo.oma.be/IRM-KMI/ozone/ozone.html

Regards,
Martin Brown

Re: Nacreous Cloud picture from 30/11

#113

Author: Rainer Thonnes
Date: Thu, 09 Dec 1999 00:00

7 lines
1118 bytes

In article <384ECD03.D2AF8B6F@virgin.net>,
 Les Crossan <les.crossan@virgin.net> writes:
>
>There's believed to be a link with this cloud and ozone depletion(????)

Someone showed me a map the other day of ozone levels for 30th Nov,
and the "hole" was centred, guess where?  Right over Edinburgh!

Re: Nacreous Cloud picture from 30/11

#109

Author: Sam Wilson
Date: Fri, 10 Dec 1999 00:00

25 lines
1972 bytes

In article <hthAqXAZcBU4Ewv6@jhall.demon.co.uk>, John Hall
<john@jhall.co.uk> wrote:

>The fortunate thing about ozone "holes" is that the mechanism is such
>that, AIUI, they can only occur in winter. 

ISTR that there's a seasonal lag, as with temperatures, so the UV max/03
min occurs in late winter early spring.  Can someone confirm?

> ... Even with the hole, the
>amount of dangerous solar radiation you will receive in Edinburgh at
>this time of year, when at midday the sun will be no more than about 15
>degrees above the horizon, is I imagine likely to be considerably less
>than you would get there at mid-summer with a full ozone layer.

The last time I got seriously sunburned (only the tops of my ears,
fortunately) was in the North of England with an afternoon's exposure at
Easter af few years ago.  I've always suspected a lagging ozone thinning
as above.

-- 
Sam Wilson
Network Services Division, Computing Services
The University of Edinburgh
Edinburgh, Scotland, UK

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads