(no subject)

[wispfox]

Fascinating:

http://toms.gsfc.nasa.gov/ery_uv/ery_uv1.html

Comments

[wcg.livejournal.com]

Yeah, TOMS is a good mission, though I must say there's a misstatement on that page I cringe at. The part where it says that UV-B is 290-320 wavelengths is just flat wrong. In fact, it's ultraviolet light with a wavelength of 290 to 320 nanometers. Each photon has only one wavelength, not hundreds of them.

[wcg.livejournal.com]

I wrote to the owner of the page about the error in the way that the term "wavelengths" was being used to mean nanometers. He's revising the text as follows:

Subject: Fwd: TOMS Erythermal UV page
Date: Mon, 10 Nov 2003 09:30:49 -0500
From: Jay Herman <jay.r.herman@nasa.gov>
To: larko@tparty.gsfc.nasa.gov
CC: Bill Gawne <gawne@cesmail.net>

Dave:

Please change the text on the UV web page (see below) from


This is an example of TOMS global image of daily erythemal UV exposure. 
Ultraviolet radiation exists to the left of the visible spectrum and is 
divided into three components (UV-A, UV-B and UV-C). UV-B (290-320 
wavelengths) is the most dangerous form of UV radiation that can reach 
ground level. Atmospheric ozone shields life at the surface from most of 
the harmful components of solar radiation. Chemical processes in the 
atmosphere can effect the level of protection provided by the ozone in the 
upper atmosphere. This thinning of the atmospheric ozone in the 
stratosphere leads to elevated levels of UV-B at ground level and increases 
the risks of 

[Error: Irreparable invalid markup ('<dna_exp.htm>') in entry. Owner must fix manually. Raw contents below.]

I wrote to the owner of the page about the error in the way that the term "wavelengths" was being used to mean nanometers. He's revising the text as follows:

<pre>
Subject: Fwd: TOMS Erythermal UV page
Date: Mon, 10 Nov 2003 09:30:49 -0500
From: Jay Herman <jay.r.herman@nasa.gov>
To: larko@tparty.gsfc.nasa.gov
CC: Bill Gawne <gawne@cesmail.net>

Dave:

Please change the text on the UV web page (see below) from


This is an example of TOMS global image of daily erythemal UV exposure.
Ultraviolet radiation exists to the left of the visible spectrum and is
divided into three components (UV-A, UV-B and UV-C). UV-B (290-320
wavelengths) is the most dangerous form of UV radiation that can reach
ground level. Atmospheric ozone shields life at the surface from most of
the harmful components of solar radiation. Chemical processes in the
atmosphere can effect the level of protection provided by the ozone in the
upper atmosphere. This thinning of the atmospheric ozone in the
stratosphere leads to elevated levels of UV-B at ground level and increases
the risks of <dna_exp.htm>DNA damage in living organisms.

We organize our data and image products by the dates a specific spacecraft
returned data. Select from the buttons below to get images and data for the
dates of interest.

To


This is an example of TOMS global image of daily erythemal UV exposure.
Ultraviolet radiation is at shorter wavelengths than the visible spectrum
(400 to 700 nm) and is divided into three components, UV-A [315 to 400 nm],
UV-B [280 to 315 nm] and UV-C [less than 280 nm]. The shorter wavelengths
that comprise UV-B are the most dangerous portion of UV radiation that can
reach ground level. Atmospheric ozone shields life at the surface from most
of the UV-B and almost all of the UV-C. UV-A and UV-B are reduced by a
small amount from Rayleigh scattering in the atmosphere. All forms of UV
radiation are reduced by cloud cover. Persistent lack of cloud cover in
some regions (e.g., Australia and South Africa) increases the danger from
UV radiation compared to similar latitudes in the Northern Hemisphere.
Chemical processes in the atmosphere can effect the amount of ozone, and,
therefore, the level of protection provided by the ozone in the
stratosphere and troposphere. This thinning of the atmospheric ozone leads
to elevated levels of UV-B at the Earth's surface and increases the risks
of <dna_exp.htm>DNA damage and other cellular damage in living organisms.

We organize our data and image products by the dates a specific spacecraft
returned data. Select from the buttons below to get images and data for the
dates of interest.
</pre>