This image is being posted to ask a question or confirm a hunch regarding the layer of atmosphere just above the horizon which I suspect to be the troposphere. The shot is looking across the Florida bay, just off the coast are a few mangrove islands and beyond that the dome lights from the keys 30 miles away. The dome lights seem to accent the layer as well as the conversion to grayscale. This location is the only one that reveals this layer usually during cooler and dryer weather. Does it have something to do with a large body of water or maybe just because of the unrestricted view of the horizon?