MadSci Network: Physics |
Note at http://www.newton.dep.anl.gov/askasci/env99/env006.htm and http://www.opt.pacificu.edu/ce/catalog/15719-GO/UVCitek.html talking about the intensity of uv thru the day but for a long time I have wondered why flourescent objects seem to glow brightly while every thing else dims and grays at sunset. Please note figure 19. http://www.opt.pacificu.edu/ce/catalog/15719-GO/Fig%2019.jpg What is the relative intensity of uv to vis and ir at sunset? Could it have to do with the refraction of the blue end of the spectrum or a reflection off the air or probably the effect of the visible color plus that of the generated light as the object flouresces. whatever, it seems neat to see flowers, a childs wading pool or the stripes on my riding mower or other objects glow so brightly as everything else grays and fades. Where can i get a chart showing a spectrum and intensity graph of light in the if to high uv for an area say central us on a summer clear day. With the white over cast look of the area this time of year i assume a lot of uv could be reflecting down off of the air as the sun gets low on the horizon as you can't seem to block the uv effect on flourescing objects with a shadow. Thanks from a very curious inquiring mind. Doc
Re: What are the relative intensities of sunlight at different times of the day
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