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Date: 29 Jul 2006 13:07:56
From:
Subject: Suntan Question (Solar ray intensity)
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Am I correct in assuming that for a given location and conditions
(i.e. ignoring clouds, dust, solar flares, magnetic field
disturbances, etc.), the intensity of the sun's rays are entirely
dependent on its altitude in the sky?
For example, they say that to avoid burning and skin damage, you
shouldn't go out between 10AM and 2PM. For some reason I seldom see
them adjust for Daylight Savings Time, but I will, so 11AM to 3PM. At
3PM on June 21, the sun has an altitude of about 60 degrees at my
location. However, on August 20, the altitude of the sun never
exceeds 59 degrees. Does this mean that I will receive higher
intensity UV radiation at 3PM on June 21 than I would at any time on
Aug 20?
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Date: 29 Jul 2006 16:47:02
From: William Hamblen
Subject: Re: Suntan Question (Solar ray intensity)
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On 2006-07-29, no@spam.com <no@spam.com > wrote:
> For example, they say that to avoid burning and skin damage, you
> shouldn't go out between 10AM and 2PM. For some reason I seldom see
> them adjust for Daylight Savings Time, but I will, so 11AM to 3PM. At
> 3PM on June 21, the sun has an altitude of about 60 degrees at my
> location. However, on August 20, the altitude of the sun never
> exceeds 59 degrees. Does this mean that I will receive higher
> intensity UV radiation at 3PM on June 21 than I would at any time on
> Aug 20?
The amount of air that the sunlight has to pass through to reach
your tender hide depends on the distance from the zenith (or the
altitude above the horizon), and the amount of UV absorbed
depends on the amount of air. This means there is a little less
UV when the altitude of the sun is 59 than when the altitude of
the sun is 60, but the difference is not enough to matter as far
as how sunburned you are going to get.
Bud
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Date: 29 Jul 2006 21:45:51
From: Sam Wormley
Subject: Re: Suntan Question (Solar ray intensity)
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no@spam.com wrote:
> Am I correct in assuming that for a given location and conditions
> (i.e. ignoring clouds, dust, solar flares, magnetic field
> disturbances, etc.), the intensity of the sun's rays are entirely
> dependent on its altitude in the sky?
To first order that is correct--one also have to take into consideration
one's physical altitude above or below Mean sea level, density of the
atmosphere (it does vary daily, seasonally, and location).
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Date: 30 Jul 2006 08:00:18
From: oriel36
Subject: Re: Suntan Question (Solar ray intensity)
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Sam Wormley wrote:
> no@spam.com wrote:
> > Am I correct in assuming that for a given location and conditions
> > (i.e. ignoring clouds, dust, solar flares, magnetic field
> > disturbances, etc.), the intensity of the sun's rays are entirely
> > dependent on its altitude in the sky?
>
> To first order that is correct--one also have to take into consideration
> one's physical altitude above or below Mean sea level, density of the
> atmosphere (it does vary daily, seasonally, and location).
This is why climate studies are in the dark ages,even those who are
genuinely concerned by the observed imabalance in global climate
conditions towards a hotter earth and subsequently more difficult
conditions for biological existence are still stuck with a 15 century
astronomical framework.
A whole new way to approach the astronomical input into climate norms
is grasp the sheer power of the Sun and leave its apparent motion and
position against the Equator as something no serious person would
consider as it shows lack of appreciation of scale and power of our
parent star.
http://www.climateprediction.net/images/sci_images/annual.gif
A wonderful way to appreciate astronomy and especially Copernican
heliocentricity,the temperature signatures reflecting local change of
orbital orientation against fixed axial orientation abolishes the
childish tendency to reference axial orientation to the Sun which is 93
million miles away.
Does not the enormous energy output arriving from such a distance not
stir men into recognising that putting the observed physical object of
the Sun against the tiny Equatorial diameter of the Earth just a
symptom of geocentricity at best and astrology at worst ?.
I guess not !
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