On 20 Sep, 19:22, "Bernard Burton"
wrote:
Ian, I do not know if there is any official rulings about this subject, but
personally I report COTRA as a remark if any of the observed cirrus is of
identifiable aircraft origin. There are not many occasions in this area,
there being many overflying jets, that the is doubt or ambiguity about
whether to report COTRA. Contrail cirrus counts towards cloud amount in an
observation, and contributes towards an assessment of the cloud type for
coding purposes.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:www.woksat.info/wwp.html
orwww.btinternet.com/~wokingham.weather/wwp.html"Ian" wrote in message

ps.com...



Hi all,

I wonder if anybody could offer some advice on contrail observation?
When conditions are right and contrails are long lasting and spread
out to lead to Cs or Ci layers do they cease to be contrails for the
purpose of cloud classification and reporting? For example, on a day
with no naturally formed cirriform clouds but with contrails that
develop into a 3 okta Cs/Ci cloud cover should this be recorded as 3Ci
or 3Cs along with a RMK that they evolved from contrails, or is it the
case of once a contrail, always a contrail and a RMK made along the
lines of "Extensive contrails, spreading to form Cs/Ci" with no
comment made upon the extent of cloud cover? I observe many contrails
being situated under several flight paths. I would be very grateful
for some guidance on how one should classify and report man made
cirriform.

Many thanks,

Ian,

Raunds, East Northants. 63m. Grid Ref SP9972
---------------------------------------------------------------------- Hide quoted text -

- Show quoted text -


Bernard & Stephen,

Many thanks for your advice and guidance, it is much appreciated.

Ian.

Raunds, East Northants. 63m. Grid Ref SP9972
---------------------------------------------------------------------