On this day in history,...

...in 1997, the journal Science published the landmark paper by William H. F. Smith and David T. Sandwell titled "Global Seafloor Topography from Satellite Altimetry and Ship Depth Soundings". This work revolutionized our understanding of the ocean floor by providing the first high-resolution global bathymetric model that combined sparse ship-based depth soundings with dense satellite altimetry data.

Prior to this development, maps of the seafloor were limited by the uneven coverage of shipborne echo soundings, which left vast areas of the ocean floor essentially unknown. Smith and Sandwell overcame this limitation by using satellite altimetry data, which detect subtle changes in sea surface height caused by the gravitational pull of underwater features. By integrating this with the existing ship soundings, they created a global topographic model that revealed previously unseen submarine ridges, seamounts, and fracture zones with unprecedented clarity.

The release of this model marked a turning point in marine geoscience, enabling better studies of plate tectonics, ocean circulation, and marine biodiversity. It has become a foundational dataset for oceanographers, geologists, and climate scientists alike. Importantly, the Smith & Sandwell database has been continuously updated, incorporating new ship data and improved satellite measurements.

As of 2025, the most recent version of the bathymetric grid offers a 1 arc-minute resolution, representing a significant leap in detail and accuracy. The data and model outputs are openly accessible through the official website at https://topex.ucsd.edu/marine_topo/mar_topo.html, serving as a vital resource for the scientific community and beyond.

Sources

•    Smith, W. H. F., and D. T. Sandwell (1997). Global Seafloor Topography from Satellite Altimetry and Ship Depth Soundings. Science, 277(5334), 1957–1962. DOI: 10.1126/science.277.5334.1957
•    Smith & Sandwell Marine Topography Web Page: https://topex.ucsd.edu/marine_topo/mar_topo.html