Water covers about 71% of Earth’s surface

Southern Ocean is south of 60° S latitude and encircles Antarctica

Marie Tharp

Global Differential GPS (GDGPS) uses fixed ground receivers to provide on-the-fly corrections to wandering GPS receiver locations. The 15-meter nominal GPS accuracy is improved to about 10 cm in case of the best implementations.

DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite)

Geoid reveals in a muted way ocean-floor topography

Topography of the world

Delivery of terrigenous sediment that accumulates as the continental rise