On Dec 23, 10:38*am, Martin Gregorie
wrote:
On Tue, 22 Dec 2009 22:21:46 -0800, Frank Whiteley wrote:

Note my comments to the article about soaring near Oxford when the
persistent contrails filled the southern sky.

Yes, and I remember the discussion on r.a.s about contrails and their
spread-out to form cirrus just after the post-9/11 three day warm period
was reported. IIRC the discussion then was about the effect of contrails
in the soaring areas beneath flight paths out of large US West Coast
airports.

--

In the USA there was a rather well done program on NOVA or Frontline
(PBS) that investigated the impact of the contrails and concluded that
contrails actually contribute to global cooling - not warming!