Hello David,
I agree that fog is more a cloud than a visibility, and I like you
description.
Best regards,
Heiko
On 2013-08-09 16:48, David Hassell wrote:
> Hello Heiko,
>
> OK with me, but I think I'd rather turn it around:
>
> Fog means water droplets or minute ice crystals close to the surface
> which reduce visibility in air to less than 1000m.
> "X_area_fraction" means the fraction of horizontal area occupied by
> X.
>
> This is because I think of fog as 'a type of cloud' rather than 'an
> amount of visibility'.
>
> What do you think?
>
> All the best,
>
> David
>
> ---- Original message from Heiko Klein (09AM 07 Aug 13)
>
>> Date: Wed, 7 Aug 2013 09:22:22 +0200
>> From: Heiko Klein <Heiko.Klein at met.no>
>> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623
>> Thunderbird/17.0.7
>> To: David Hassell <d.c.hassell at reading.ac.uk>
>> CC: Jonathan Gregory <j.m.gregory at reading.ac.uk>, cf-metadata at cgd.ucar.edu
>> Subject: Re: [CF-metadata] Standard name for fog as area fraction
>>
>> Hello David,
>>
>> I think we agree on the important parts about fog:
>>
>> * visibility in air < 1000m
>> * caused by water (i.e. not by dust, which would be haze)
>> * near-surface (~ human eyes height)
>>
>> Coming to the exact wording is more difficult. The term 'cloud'
>> might include dust (Saharan dust clouds) and exclude radiation fog,
>> so I wouldn't like to use it. 'humidity' is invisible as you note,
>> so I will drop that. water droplets might exclude ice-fog. What
>> about:
>>
>>
>> fog means visibility in air < 1000m due to water
>> droplets or minute ice crystals close to the surface.
>> "X_area_fraction" means the fraction of horizontal area occupied by X.
>>
>
> --
> David Hassell
> National Centre for Atmospheric Science (NCAS)
> Department of Meteorology, University of Reading,
> Earley Gate, PO Box 243,
> Reading RG6 6BB, U.K.
>
> Tel : +44 118 3785613
> E-mail: d.c.hassell at reading.ac.uk
>
--
Dr. Heiko Klein Tel. + 47 22 96 32 58
Development Section / IT Department Fax. + 47 22 69 63 55
Norwegian Meteorological Institute http://www.met.no
P.O. Box 43 Blindern 0313 Oslo NORWAY
Received on Mon Aug 12 2013 - 01:37:59 BST
