Dynamic Visibility
 

I was at a talk given by a Retired Airline Pilot. He mentioned the term Dynamic Visibility. He went on to say that for example, visibility may be reported as 2000 metres, however if it was raining at the time the visibility on the take-off roll would be reduced due to the impact of water droplets on the windscreen and exacerbated by the forward motion of the aircraft. So in fact the vis may actually be 1500 metres.

I have done a search on this term with no success.Does anybody have any info on this subject?

Hmm...interesting. Can't help you but yet still very interesting...

I have not encountered the term in a detrimental sense, but I have with something similar that ‘improves’ low visibility - an effect known as ‘streaming’. This is most noticeable in fog operations where the runway lights appear as a stream of information; the more distant lights appear to be seen at ranges more distant than the reported visibility would allow.
I understand that this might be a form of ‘Gestalt’ – the mental need for symmetry or completion of an expected pattern. The mental picture predicts the next light to be seen, thus it might be classed as expectation bias.

I've never heard the term, but have certainly experienced the effect. I suspect that the term is his own and it seems to have achieved its purpose because you remembered it. The chances are that, from now on, you'll always remember what it's all about.

In fact, just thinking about it now, it's probably as good a term as any to identify the effect.:ok: