There are hundreds of projects where they use radar altimetry to measure the ocean surface very accurately and this surface, in turn, reveals the shape of the ocean floor. This works because the shape (or topography) of the ocean floor means the gravitational pull is different in that area because of changes in the density -- this is then reflected in the shape of the surface of the water.
Scale is exaggerated Image credit: NOAA: Datums, Heights, and Geodesy |
This map of the ocean floor is one such result of mapping the ocean surface topography:
Image credit: NOAA |
And
Image credit: global marine gravity model from CryoSat-2 and Jason-1 |
But it is EXACTLY like that -- except you didn't correctly compute the gravitational influence so the surface has tiny undulations that mirror the ocean floor.
Here is more water 'finding its level' - as you can see, water is perfectly happy to form a spheroid. Attempts to replicate this 6 feet from the Earth under the full influence of Earth's gravity are the very definition of disingenuousness.
Rotating Sphere of Water in Microgravity |
See Also:
- NOAA: Datums, Heights, and Geodesy << very informative slide-deck
- Geodesy for the Layman
- Geodesy in the 21s Century
- GPlates Portal: This one in particular Vertical Gravity Gradient Grid
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