clouds

the clouds look very pretty right?? especially if they appear at night.
too bad this type of clouds only appear in the colder region such as the scandinavian countries...during winter time..but it will be a spectacular view..

but there is a hard fact behind the clouds formation...they are only formed due to cold temperature of the stratospheric layer in the atmosphere and mainly composed of mixtures of naturally occurring water and nitric acid.
the clouds surface provide a good surface for ozone-destruction chemical reaction, especially those involved compounds such chlorine containing compounds...

sigh..such pretty clouds...but what a grieve effect to the environment