Before the advent of modern oceanographic instrumentation, scientists possessed only rudimentary ways of exploring our oceans. Surface currents could be inferred from their effect on ship’s tracks, and from the net drift of floating objects released at one location and found much later at another, like a message in a bottle from another place. Tracking drifting objects is still an important technique, but now the objects are carefully designed floats with drogues, and they are tracked using satellite navigation and communications. During the last 50 years, many instruments have been developed for measuring currents at all depths, not just at the surface.
From past to present
Scientists aboard Falkor have been measuring the small scale structure of currents and water properties (temperature, salinity, oxygen, etc.) for the last few weeks. On previous cruises the science party has worked in the western Pacific, but Dr. Richards and his team wanted observations from the central Pacific for comparison—are the small-scale structures as prominent there as they are in the west? The present El Nino episode
Crazy currents
On the surface of the ocean there is a mixed layer that can range from a few meters to tens of meters. The science team is looking under that layer, where mixing still occurs, but at slower rates. This mixing is a result of the vertical shear