Hallo Bertram,
der "Herr der Blitze" ist Dr. Andrew Young aus San Diego, hier der Einstiegslink zu Deiner Frage:
http://www-rohan.sdsu.edu/~aty/observing/advice.html
Kernsätze: "The primary consideration is that [classical]
green flashes are related to mirages. By a long-established theorem of atmospheric optics,
mirages can only occur below the astronomical horizon (assuming the layers in the atmosphere are 'horizontal' — a condition that is not always met in the real world). So your apparent horizon must usually be formed by some obstacle lower than your eye."
Das bezieht sich aber auf den klassischen Grünen Blitz als letzten Strahl der Sonne sowie auf die sich in Luftspiegelungen oben von der Sonne ablösenden grünen Segmente.
Auf Deine Beobachtung trifft eher das hier zu:
http://www-rohan.sdsu.edu/~aty/explain/ ... /rims.html
Kernsätze: "
Elevated-horizon flashes - However, there is one place where
green-rim flashes can be seen, even with the naked eye. The rapid decrease in extinction and atmospheric reddening with altitude means that
if the [sun's] rim is occulted by an elevated obstacle (such as a mountain, or even the ridge line of a building),
so that the upper limb is isolated at an apparent altitude of a degree or two, where it is most visible, there's a chance of seeing this 'textbook' flash with the naked eye. ... [Es folgt eine Liste historischer Beobachtungen] ... This mechanism may also explain some cloud-top flashes."
Gruß, Elmar
