The contrails of Shadow1.jpg and Shadow2.jpg cast shadows into
the "blanc air". The shadows are reproduced on cloud particles
in the air which occur in such low number densities that the observer
does not notice them as cloud anymore.
At Shadow3.jpg and Shadow4.jpg an aircraft contrail produces shadows
during sunset. They fall on a Cirrus cloud layer which is located
above the contrail.
Shadow5.jpg shows two contrails on which clouds of the neighbourhood
cast their shadows at.
Shadow6-10.jpg display contrails above a Cirrostratus layer. At
high sun level they cast their shadows onto these clouds.
Shadow11.jpg and Shadow12.jpg: The aircraft was found to be between
a Cirrus cloud layer with embedded, already aged contrails and a
discontinuous Altostratus cloud layer. At the time of exposure a
larger gap appeared in the Altostratus layer. The contrails cast
a weak shadow onto the haze below the wing.
Shadow13-20.jpg: The photographer took the images from an airplane
which was located between the shading contrails and the "projection
surface" consisting of a closed stratus cover here.
Shadow21-24.jpg: After sunset the contrails are already shadowed
by the earth, whereas the clouds at larger altitudes (Cirrus clouds
and other contrails) are still illuminated by the sun.
Contrails of aircrafts moving from east to west are worthwhile to
observe at sunrise. Then extremely long contrails that are still
located in the dark will be illuminated more and more from east
to west when the sun rises up. Under these conditions the observer
sees how the sunlight migrates along the contrail, until it has
outrun the aircraft. It happens that way, since the projection of
the rising sun on the stripes moves faster to the west than the
subsonic aircraft. It is just a spectacular perspective. (The situation
would be different with a supersonic aircraft).
Shadow1.jpg: S. Borrmann, Pulpit Rock, Carinthia, Austria, 30 December
2001, 2 p.m.
Shadow2.jpg: S. Borrmann, Ingelheim, Germany, June 2002
Shadow3+4.jpg: S. Borrmann, Ingelheim, Germany, June 2002
Shadow5.jpg: S. Borrmann, Pulpit Rock, Carinthia, Austria, January
Shadow6-10.jpg: S. Borrmann, MPI for Chemistry, Mainz, Germany,
30 June 2004, 3:22 p.m.
Shadow11+12.jpg: S. Borrmann, flight LH 974 from Frankfurt to Munich,
9 September 2005, 4:27 p.m.
Shadow13-20.jpg: S. Borrmann, flight LH 4172 from Frankfurt to Lyon,
7 January 2006, 1:14 p.m. to 1:56 p.m.
Shadow21-24.jpg: S. Borrmann, Alpe d'Huez, French Alps, 8 January
2006, 5:00 p.m.