1. MikeC

    MikeC Senior Member

    Looks like the chemtrail activism is working, because why else would TPTB be doing stuff like this??

    http://www.bbc.com/news/science-environment-39286079

     
    Last edited by a moderator: Mar 22, 2017 at 7:36 AM
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  2. NoParty

    NoParty Senior Member

    Hmmm...I can't say that "activism is working" was my first impression:

    They have this Moore fellow saying:
    "We know these contrails and cirrus clouds have a warming effect on the Earth's climate..."
    but isn't that the opposite of what most chemtrailers believe? Don't they think that nefarious
    sources are spraying these plumes in order to reduce sunlight, and to lower the temperature?
     
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  3. MikeC

    MikeC Senior Member

    Sorry - I should probably have put a smilie or 12 on the post - but i'll give you dollars to knobs of goat dung that such a claim will be made by believers when they find this and justify it against their mantra.
     
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  4. Ross Marsden

    Ross Marsden Senior Member

    Even if there is no soot, sulfur, or other introduced ice nuclei, some of the condensation droplets will spontaneously freeze, and there will still be visible contrails and aviation induced cirrus.

    Ice crystal formation by Homogeneous Freezing
    (bullet points and a diagram)

    Ice and Mixed Phase Clouds
     
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  5. Clouds Givemethewillies

    Clouds Givemethewillies Active Member

    I imagine that the plan is to make the ice crystals bigger, and the clouds optically thinner.
     
  6. Hama Neggs

    Hama Neggs Senior Member

    This seems related to the question which was raised some months ago as to whether contrails would be formed by introducing ONLY nuclei particles but no added. Apparently you are saying that at some temperature no nuclei at all are needed?
     
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  7. Spectrar Ghost

    Spectrar Ghost Senior Member

    Precisely. It's called homogenous nucleation.

     
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  8. Hama Neggs

    Hama Neggs Senior Member

    Maybe it's not that relevant to contrail formation since nuclei are always present, yes?
     
  9. Ross Marsden

    Ross Marsden Senior Member

    Well, no. There are two kinds of nuclei.
    There are Cloud Condensation Nuclei. There are plenty of them and they are everywhere. You cannot get water supersaturated air (in the free atmosphere), that is RHw above 100% because the CCN are always there to initiate condensation.
    There are Ice Nuclei. There are very few in the free atmosphere. Aircraft exhaust provide them in the exhaust plume, and they are in the condensed water droplets, and the droplets readily freeze on them.

    Ice will not nucleate on a condensation nucleus; it needs an ice nucleus.

    That there are none (or very few) naturally occurring in the atmosphere is why you can have vast regions of ice-supersaturated air where the RHi is above 100%, and up to like 140% at the point where RHw is just reaching 100%.
    And this is why large parts of the sky can be filled with persistent contails that cannot dissipate in these ice-supersaturated regions.

    If there were Ice Nuclei, then these ice-saturated regions would be full of ice cloud, just as water-saturated regions are full of water droplet cloud.
     
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  10. Trailblazer

    Trailblazer Moderator Staff Member

    Do you think it is the case that with more and more flights, the increasing "background amount" of ice nuclei could mean that ISSRs (ice-supersaturated regions) will tend to simply spontaneously fill with cloud in the future? I don't know what the typical residence time of these particles is, but if it is relatively long then you would expect the increasing number of flights to keep increasing the levels of ice nuclei in this part of the atmosphere.

    If the nuclei linger after the aircraft have passed, then they could drift into ISSRs and initiate "contrail" formation even when the plane is not near. Or do the particles have to be relatively freshly produced in order to function as ice nuclei?
     
  11. Ross Marsden

    Ross Marsden Senior Member

    Yes, I do think that logically follows. Maybe the trails of sparse soot and SO2 are too diffuse/dilute, or few relative to the volume available, for trails of ice cloud to be visible.