Your post is most appreciated, Lookang. I found it very interesting.
It does not seem to explain what I saw, however. I actually approached 'my bow' from outside the SW end of the bow at about 120 degrees, not in front of it. I do not recall for certain if I could see the air disturbance from the back side, but I think so - the air had a wavy appearance. I should have made my observation more precise, but... I was awe struck while trying to record what I was seeing.
I did not specifically note the arc of the rainbow as to its height, but as I remember the arc was more shallow than normally what I see.
The disturbance of the air really makes me wonder what? and why?, it is as though the air were ionized in some way. Is there a 'channel' of some sort generated in the air upon which to produce the bow itself???