Contrails
What are ‘contrails’?
Contrails are thin and long clouds that you can see a little bit behind an airplane when it is flying ca. 10km high. There the air temperature is
–40°C.
What are contrails caused by?
The exhaust gases from the engines come in contact with the much cooler air. The gases rise (because they are hotter than the surrounding air) and meanwhile they expand. The gases cool so fast that water particles condense and finally freeze. This forms contrails.
The weather and contrails.
Contrails tell a lot about the atmosphere at great heights. When the contrails disappear quick, the chance that the weather conditions change is small. When the contrails stay long visible and they are blown out, then there is more chance that the weather conditions will change in the following days.
Contrail Spotting: a variant of plane spotting.
By contrail spotting you photograph airplanes when they fly high and they form contrails. For photographing, you will need a telescope where you can mount your camera on. Of course, you can also just watch the airplanes with a binocular that has a strong magnification factor. A tripod is recommended to eliminate vibrations.
