Water could look blue, or it could look more grey. It's just the sky reflecting in the ocean, and the reason it looks bluer in the tropics is because of salinity, clearness and depth of the water. If it's cloudy, than yes. The water will look more grey. You don't have to be a pilot to know what water looks like from above. http://www.google.ca/imgres?q=ocean+from+a+plane&um=1&hl=en&biw=1920&bih=857&tbm=isch&tbnid=w_SYjenJZBLXoM:&imgrefurl=http://www.freerepublic.com/tag/b2/index&docid=RiBaZXeN2XyztM&imgurl=http://chamorrobible.org/images/photos/gpw-200905-UnitedStatesAirForce-090512-F-2482B-025-B-2-Spirit-stealth-bomber-Western-Pacific-Ocean-20090512-large.jpg&w=2306&h=1700&ei=L4LNTvH_LeHiiAKC56zyCw&zoom=1&iact=hc&vpx=436&vpy=318&dur=324&hovh=193&hovw=262&tx=124&ty=105&sig=107901978826604628177&page=1&tbnh=151&tbnw=205&start=0&ndsp=33&ved=1t:429,r:9,s:0