1. cloudspotter

    cloudspotter Senior Member

    On a recent walk in the hills my day started like this DSC_0717.JPG

    The relative humidity chart from InstantWeatherMaps.com shows around 50% RH at 300mb. The red dot is my approximate location.


    By the end of my walk the skies looked like this


    The relative humidity chart from InstantWeatherMaps.com shows greater than 90% RH at 300mb.

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  2. derwoodii

    derwoodii Senior Member

    i been waiting to show this in other threads i will see if can show it here


    But to my frustration SQ297 seem not to follow the same flight path each day and can travel over head 1000 clicks north of me or as today just beyond my sight yet for a few days over 2 weeks it went right over head

  3. derwoodii

    derwoodii Senior Member

    well it took sometime for the atmosphere conditions and flight SQ297 to go over my head but today it all came together..

    well will ya look at that out my window 6/2/18 at 615 am today SQ297 almost right over head & no trails


    chugging along nicely 37000FL I still wonder why/how the same flight can go 1000 clicks to my north yet still aim at fuel efficiently at Christchurch,,, ? upper jet stream winds im suspecting

    because its too dang dry at 35000
  4. Trailblazer

    Trailblazer Moderator Staff Member

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  5. cloudspotter

    cloudspotter Senior Member

    8am 01/05 Newcastle-Upon-Tyne



    12 noon


  6. Clouds Givemethewillies

    Clouds Givemethewillies Active Member

    The tropopause seems a bit low for contrails, although looks good for aerodynamic ones. :)
  7. cloudspotter

    cloudspotter Senior Member

    Unfortunately I don't have a good view of the sky from my desk so wasn't able to see any of the trails being formed
  8. Clouds Givemethewillies

    Clouds Givemethewillies Active Member

  9. Trailblazer

    Trailblazer Moderator Staff Member

  10. Clouds Givemethewillies

    Clouds Givemethewillies Active Member

    It is a false colour plot of backscatter (colour scale) against time (X axis) and vertical range ( Y axis) as clouds/aerosols/contrails etc. advect (with the wind) over a Met Office lidar ( in this case for Eskdalemuir). The cloud base is marked in black and the colour is an indication of the amount of backscatter in (relatively) arbitary units, as in the case of these lidars, which operate in the IR, there is virtually no air backscatter to use as a reference value. The light blue, in this case, near the ground is aerosol backscatter in the boundary layer, and the rest is cloud/contrails of various sorts. The black dots higher up are probably contrails which pass through the laser beam in a relatively short time. I should add that the signal to noise decreases with height as 1/(range squared), so it runs out of steam higher up, although it can still see the denser clouds (but not aerosols).
    Last edited: May 2, 2018
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