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Air Glow

2 June 2019

At http://spaceweather.com (June 2nd 2019) we have several days of reports of noctilucent clouds circling around the Arctic and providing photographers with a lot of images (which can be seen at the link). The circling process takes around 5 days as a result of a planetary wave that is driving the motion. Noctilucent clouds over Europe appear every time 5 days elapse. The noctilucent clouds are also expanding in size. The swirling is caused by a planetary wave, temperature and pressure that form in the atmosphere in response to Coriolis forces. All rotating planets with an atmosphere have such waves.


However, the photograph below is not of noctilucent clouds but of airglow over the Pictured Rocks Ntional Lakeshore in Michigan. A stream of solar wind was buffeting earth's magnetic field and produced the airglow (rather than an aurora). It looks like an aurora but it is not …

   … air glow is caused by chemical reactions in the upper atmosphere. Air glow occurs in day time and afterglow at night. Gravity waves propagating upwards provide the green and red colours with the rippling effect.

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