OK - so the real question here was: Does the Rainbow Covenant Disprove the Flood?
I say you cannot disprove myth that certain people choose to believe irregardless. How would I go about disproving area 51 and Roswell?
However, rainbow covenant does raise some startling questions...just on the physical science side -
Did god change the laws of diffraction just after the flood? There really was enough condensed water droplets or ice crystals in the upper atmosphere to actually obliterate the sun completely? All over the earth? For about 1500 years +++ since Adam? What would such a thing do to plant growth and atmospheric pressures? What would it do to the climate? Could the atmosphere actually sustain that much cloud cover for that long? If god had to maintain the canopy outside natural law, then it sort of looks like he was planning to flood man sometime from the get-go and was just holding back his water, so to speak...
And then, there is a moral/religious side:
Why did god destroy all those people at once - and, then immediately promise to never do it again (at least not by water)? If he wanted to get those bad angels, this was bad strategy...even WT says they just dematerialized and floated back up to the bad side of heaven. (OK - he got the Nethinim and their rape victim mothers, but they were the innocent parties in this sex crime). Was he admitting it was all a mistake? Were they really that much worse than people now? (well, manifestly not - we are going to get nuked at big A in a few years r.e.WT ) What's the big deal about killing by water deluge - if you are planning to later kill by fire and pestilence, then this rainbow covenant idea is all kind of a big hoax. (I.E. - rainbow means next time will be worse) I think I would just as soon drown as get roasted or succumb to the black plague.
For me, it is sort of a grand morality play as myth which tries to teach the danger of unnatural societal behavior - having implications on common human law, environmental science, etc. today. And, maybe inspired by some localized flood...other than that, too many problems for a literal interpretation.
James