How to simulate a desert's "mirage" effect ( heated air's turbulence)using compositor

Hi there
this is a quick tip showing how we can simulate the so called “mirage” effect ,that is, the turbulence in the flow of heated air seen oftentimes in deserts due to the differences in air layers temperatures
we’re going to use Displace node,along with a keyframed (its “offset” parameter) procedural texture and a grayscale mask,in order to simulate this “mirage” effect in compositor
This is planned to be just a glimpse of a full length series of tutorials presenting how we can rig,animate and post-process the solar farm scene showing up in this quick tip

the sky ime-lapse movie clip,that has been used as a backing plate composite element (simulating the “skydome”) is courtesy of Bresson Thomas :

and shared and Creative Commons Attribution 3.0 Unported License
Thanks for watching