In article , "Alastair McDonald" k writes:

"Keith Dancey" wrote in message
...
In article , "Alastair McDonald"
writes:

"Fears over increase in skin cancer as scientists report that climate
change
continues to destroy the earth's protection." See;
http://www.guardian.co.uk/life/scien...471075,00.html

This article provides confirmation to me that the ozone layer over the NH
could be the cause of this year's "cooler" spring.


How might reduced stratospheric ozone reduce tropospheric temperature?

Because the ozone is not trapping the radiation in the stratosphere, the
stratosphere is cooler. The stratosphere forms an inversion layer at the
tropopause and this temperature controls the average temperature at the
surface via a standard lapse rate.

Putting it another way, the tropopause temperature is the minimum temperature
of the troposphere. An ozone hole will reduce that minimum temperature and
so all the tropopause can become cooler.


The stratosphere is cooler because greenhouse gases in the troposphere are
preventing a proportion of the outgoing longwave radiation from reaching it
and heating it. This drop in stratospheric temperatures increases the
efficiency of the photochemical reactions which destroy ozone...

The altitude of the tropopause adjusts to the changes in temperature of
the stratosphere, so your standard lapse rate still holds: the surface
temperature is not effected.



Or, say, increased Solar UV penetration reduce surface temperature?

IMHO, The high energy photons of UV light tend to be absorbed by latent heat
and so cause little sensible heating.


Ummmmm...




And is this year's Northern Hemisphere spring and cooler than usual, anyway?

It is cooler than it would be due to global warming.


There have been much greater ozone holes over the Antarctic, over a much longer
period of time, but I have not noticed Southern Hemisphere springs to be reported
as "cooler than expected".

There have also been Northern Hemisphere ozone holes before, too, but I have not
noticed any corresponding Northern Hemisphere spring-time "cooling".

If the correlation isn't showing up on the records, and the theory doesn't
hang together, then I think the idea is mistaken.


Cheers,

keith


---
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