Frozen Smoke

4 Jul 2017

Noctilucent cloud activity is occurring over Europe in early July. See July 3rd 2017 ...

     ... Recent nightfalls have brought glowing ripples of electric blue. The image above come from Slovakia. These clouds are telling us something about weather in the Mesosphere. It's very cold up there. Noctilucent clouds form when summertime wisps of water vapour rise to the top of the atmosphere, coating specks of meteor smoke with fragile crystals of ice. The process requires temperatures as low as -128C. In early June a heat wave in the Mesosphere temporarily removed noctilucent clouds - a blast from the Sun perhaps. Their return at the back end of June coincides with a quiet Sun.

Weather Eye in The Times of London turned his attention to noctilucent clouds this past week - night shining clouds. These ethereal, electric blue tendrils appear only in the summer months, at twilight - just after sun set. They are the highest clouds - at 52 miles above the surface of the earth. Weather Eye says the water vapour gathers on soot left behind by meteors burning up in the Mesosphere. They began in late May this year but then vanished in the first half of June. The Mesosphere had warmed up, melting the ice crystals (or frozen smoke).