Mysterious striped currents


It may seem hard to believe, but the oceans have stripes. These stripes are not visible without looking very closely, but they are visible through their effect on currents, temperatures, and sea surface heights.

They were first spotted in a careful analysis of the Mean Dynamic Ocean Topography (MDOT) dataset, but had to be confirmed by looking directly at ocean buoy and vertical temperature profile data.

These stripes are being reported in an upcoming issue of Geophysical Research Letters by an international group of scientists lead by Nikolai Maximenko at the University of Hawaii.

Each stripe is approximately 200km across and they are oriented roughly east-west. In the northern hemisphere, they appear to be oriented more southwest-northeast at an angle of 13 degrees, while in the southern hemisphere they are closer to northwest-southeast at an angle of 9 degrees.

Finding these stripes was difficult because they are very subtle features that are superimposed on much larger ocean current, topography, and temperature fields. The stripes have velocities around 1-1.5cm/s, while major ocean currents often travel at 40-50cm/s.

The change in sea surface height from one stripe to the next is roughly four centimeters