2007. december 5., szerda

Sky Haloes in Southern Germany

Although this year only few haloes appeared over Germany, I could observe the second complex halo display on Mt. Wendelstein. In the morning I saw my first subsun in this year, which appeared in freezing fog. Later a veil of cirrostratus from a low pressure area over the Mediterranean Sea crossed the Alps from the south. Under those weather conditions, large halo displays can be seen very often. In my own statistics, 80% of all larger halo displays appeared when there was a southerly stream of air over the Alps, or under foehn conditions. And also this time there was a large choice of haloes in the southern part of the sky, which lasted for about two hours and a half. Between 10.10 and 12.45 CET the 22°-halo, a bright upper tangent arc and a faint Parry arc, both sundogs with Lowitz arcs, the parhelic circle, an almost complete supralateral arc, a faint infralateral arc on the right side, and a complete sun pillar were visible. Unfortunately, the haloes appeared only over a small area on the northern rim of the Alps. So except of me, only my husband who was down in the valley at that time, could enjoy similar haloes.

1 megjegyzés:

  1. Very nice image of this complex display, Claudia!
    Perhaps one of the reasons that such great displays occur in foehn-conditions is that often all low- and mid-level clouds dissappear because of drying out of the lowest kilometers in the troposphere: that is, only the upper clouds remain! But of course it's also possible that in such southerly flows the cristallography becomes just perfect for such complex displays.