A search turns up to previous threads on this subject but neither seemed to offer a definitive conclusion either way and both were more general than my case. I have a long running debate with my father-in-law regarding the curvature of the horizon. Please note that I am not referring to the curvature in the medial plane (as one is facing the ocean), but rather in the frontal plane.
The debate is as follows.
At his Miami Beach apartment building on the 8th floor, one can see the ocean. The view is partially obscured by the building itself, as well as the adjacent building, so it is not possible to see all the way down the beach. You can see the building here. The apartment is located in the section of the building directly to the left of the larger of the two pools, across the large patio section. He argues that he can see curvature at the horizon while I maintain that while he may think he does, it is impossible for the human eye to actually perceive the minimal curvature.
Based on my rough calculations, the horizon is approximately 12.4 miles away at that height (~100ft). Estimating the amount of visible horizon (due to the blocking buildings) at that distance as a generous 20 mi, I believe that the difference in “height” between the midpoint of the visible arc and the side points is ~16 ft. I do not believe that it is possible to detect a difference in height of 16 ft at a distance of 12.4 miles. To put it another way, if we were to approximate the horizon as a short, wide triangle, the “slope” of horizon would be 1.6 ft rise for every mile of horizontal distance. Is it really possible for a human to perceive such a minimal slope at a distance of 12.4 miles? I contend that it is not.