🚀 go-pugleaf

Greig Ebeling <eggsoft@sydney.dialix.oz.au> wrote in article
<5eepj0$e0o$9@coffee.DIALix.COM>...
> No, Jay.  NASA's satellite only measures ozone depletion.  It does not
> measure increases in surface UV-B, and certainly has no way of
> measuring UV-B exposure, which is heavily dependent on human
> behavioural patterns.  I suspect the "6.8%/decade" figure is for ozone
> depletion, but perhaps I am wrong.  Since you posted this figure, I
> welcome your explanation of its meaning.
> 
> 
> ...Greig
> 
> 

In point of fact, the TOMS instruments measure radiance from the earth
and irradiance from the sun at 6 different UV wavelengths.  The amount
of ozone in the atmosphere is then calculated using the radiance and
irradiance measurements.

Other quantities can also be calculated from those measurements, 
including surface UV radiation.  This was recently done by Herman, et
al. using the 14.5 year data record from Nimbus-7/TOMS.  The results 
were published in a paper in the Aug 1, 1996 issue of Geophysical 
Research Letters.  

In this paper, Herman et al. determined a 6.8% per decade increase 
in UV radiation at 55 degrees north latitude, where major populations in
North America, Europe, and Asia live.

For more information, see 

ftp://pao.gsfc.nasa.gov/pub/PAO/releases/1996/96-047.txt

or, better yet, read the paper.

Colin Seftor