Commons:Featured picture candidates/Image:Oblique rays 02 Pengo.svg

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Solar radiation has a lower intensity in polar regions because it travels a longer distance through the atmosphere, and is spread across a larger surface area. v3: Northern Winter v4: Spring/Autumn

  •  Info created by Pengo - uploaded by Pengo - nominated by Cacophony --Cacophony 07:43, 29 June 2007 (UTC)[reply]
    • Second diagram (03) shows Northern Winter tilt, and the last (04) attempts a Spring/Autumn tilt, although it's probably not enough of one.
  •  Support I think it elegantly illustrates a simple concept that has major effects to the world that we live in. --Cacophony 07:43, 29 June 2007 (UTC)[reply]
  •  Oppose. Unfortunately, the concept is not that simple, and this image is in my view very misleading. It doesn't show the earth's angled rotation axis, and seems to imply that the sun's rays are always parallel to the equator, which is not the case due to the oblique angle the axis makes with the plane of the earth's motion around the sun. The text even states that "Solar radiation in tropical areas (i.e. lower latitudes, nearer the equator) has vertical rays", which as a general unqualified statement is simply wrong (it happens at local noon only twice a year). To explain the effect properly you'd need at least to mention if not show both time of day and seasonal effects. Also, the fake landmass worries me; why not a real outline? --MichaelMaggs 08:03, 29 June 2007 (UTC)[reply]
    • Thanks for the comments. The diagram is to show why the poles are colder than the equator, so I'm not sure how adding axial tilt would do anything but confuse things. I've changed the text to note this simplification, and to say "more vertical" (if that's a term) rather than just "vertical". I didn't use real land mass because it's too hard to find a picture of the Earth with the equator in the middle, let alone in svg or at the right level of detail; and i wanted to the avoid the politics of choosing which side of the Earth was facing the viewer. The time of day being noon is implied by positions of the sun and Earth and the areas of focus. Pengo 10:53, 29 June 2007 (UTC)[reply]
  •  Oppose i do think you should tilt the equator line, remove the outline of the atmosphere ( wich gives the impresion of being solid) , also remove the yellow scale at the size it gives really no extra information. and the arrow heads in the sollar rays are not really necesary either -LadyofHats 12:28, 29 June 2007 (UTC)[reply]
    • I've incorporated your suggestions, and attempted a couple of different "tilts". I'm still not sure they help at all other than to confuse matters by introducing seasons.
  •  Oppose - 1st: This is not the best way to illustrate the concept; 2nd: that is not the only reason why the poles are colder than the equator, and 3rd: the picture is misleading, like MichaelMaggs said. To show that the altitude of the sun above the horizon has a strong influence on the flux of energy at the surface I would prefer to depict a flat ground, with two similiar "cylinders of rays" coming from different angles. - Alvesgaspar 22:35, 29 June 2007 (UTC)[reply]
    • Sorry, what other reasons are the poles colder other than axial tilt? The cylinders of rays is a different way (not a "better way"), and would make it difficult to show the rays have to travel further through the atmosphere. Although it doesn't change anything, please note also that this diagram that I seem to be defending now isn't completely my own design, but is based on those found in a couple of textbooks. Pengo 23:55, 29 June 2007 (UTC)[reply]
    •  Comment - Here is a picture illustrating what I mean, from the time I was teaching these things (sorry to be in Portuguese). The angle of incidence of the rays, combined with the albedo of the surface has also a strong influence on the amount of energy being absorbed (or reflected) at the surface. In the ice-covered polar zones, almost all direct energy from the sun is reflected because it is white and the angle is small. In short, the angle of incidence affects the heating of the surface in 3 different ways: lenght of atmospheric track, variable flux and variable reflection. - Alvesgaspar 10:08, 30 June 2007 (UTC)[reply] 
result: 1 support, 3 oppose, 0 neutral => not featured. (Rule of the 5th day) Simonizer 08:04, 4 July 2007 (UTC)[reply]
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