On 19/06/17 15:07, wrote:
Thanks All Is there any reason to suppose that TM air is more likely
to be associated with lower levels of ozone in the stratosphere than
any other air mass? Do high surface temperatures have any relevant
effect at all ? I don't see why. Surely surface UV levels are
simply a factor of solar altitude and cloud/haze? (Perhaps humidity
plays a role ?)


Back in the early 90s, when we produced regression equations from model
output to produce ozone and uv fields, the parameters used included 30
and 150hPa temperatures as well as latitude and total thickness. I think
the upper-atmosphere data was used to make an educated guess at the
ozone levels. No idea what's done these days.

I remember hearing that it's not just the amount and thickness of cloud
but also the type. For instance, half-cover of cumulus might increase UV
rather than decrease it.

--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
Never approach a bull from the front, a horse from the rear,
or an idiot from any direction! [Irish proverb]