Air Pollution at FL 36?

Discussion in 'The Okie Corral' started by 8Ring, Feb 3, 2010.

  1. 8Ring

    8Ring

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    Sunday I was flying from Philadelphia to Denver on a United 757, leaving Phil International at 16:35. I was sitting on the left (south) side of the plane.

    When we reached FL36 I noticed what appeared to be a dark gray line of dust just above the plane, reaching toward the horizon to the south and west. It was hard to estimate the thickness of this line, but I'd guess it was several hundred yards, at most. Below this line looking toward the horizon to the south, southwest, and west (toward the setting sun) the sky was a reddish orange color. It reminded me of the color of the late afternoon summer sky in LA years ago.

    Above the gray line, the sky was clear blue, turning to dark blue and black above the plane and toward the southeast.

    The dark gray line was similar to the tops of winter inversions I have seen from time to time in the Denver area.

    Was this air pollution? Why was there such a clear line of demarcation at this altitude? (I thought that the winds at this elevation would have broken up any pollution.)

    Chris
     
  2. sns3guppy

    sns3guppy

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    You may have been seeing smoke, ice crystals, dust, volcanic ash, or other debris marking a line between layers. Not at all uncommon.
     

  3. sopdan

    sopdan

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  4. Skyhook

    Skyhook

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    Yup, we here in the east downwind from Ohio, etc., get that brown/orange layer fairly often.