The ocean is a very dynamic place. One phenomenon that has stumped researchers for years is how swirls of circular currents multiple kilometers wide, known as eddies or ocean rings, stay intact. Ocean rings are crucially important for transporting heat and nutrients throughout the ocean and can last from a few months to several years.
A new study published in the journal Geophysical Research Letters by Larry Gulliver and Professor Timour Radko explains what makes some ocean rings last up to a decade while others dissipate within a few months: seafloor topography.
This new understanding of how the ocean floor affects surface currents will improve complex, numerical models used by the Navy’s meteorology and oceanography (METOC) community.
Gulliver and Radko call their finding the “sandpaper effect” – making reference to the small abrasive particles of sandpaper that can grind down much larger objects. In the same manner, the small-scale texture of the seafloor slows down currents near the ocean bottom, which improves the longevity and stability of ocean rings near the surface.
Scientists have been trying to figure out what makes large vortices stable and long-lived for about 50 years, but no one thought to look at the ocean floor’s small-scale topography because ti seemed too distant to impact these ocean rings. Topographic roughness is usually not even considered by scientists when looking at surface water activity.
https://phys.org/news/2022-06-unravel-stability-mystery-ocean.html