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2. Tracking the Ocean Surface Currents 
with Drifters

Expedition Menu

1. Introduction
2. Tracking Drifters
3. Drifters Pacific
4. Drifters Atlantic
5. Drifters Indian
6. Velocity Pacific
7. Velocity Atlantic
8. Velocity Indian
9. Global Circulation
10. Counter Currents
11. Boundary Currents

Ocean currents are tracked in a number of ways, such as by:

1. following the paths of drifting buoys,

2. using current meters at fixed locations,

3. using acoustics (sound),

4. or by tracing temperature or chemical properties of the water.

Let's join the R/V Ronald Brown to deploy drifter buoys in the Pacific Ocean, prior to analyzing drifters in all of the ocean basins.

R/V Ronald Brown of NOAA

On this expedition, you will participate as a scientist in generating a conceptual diagram of the surface circulation in the ocean basins.

Deploying a Drifter Buoy of WOCE Experiment
Courtesy of Project Oceania

The Drifting Buoy Data Assembly Center has generated the data for you by tracking drifters with satellites -- you will analyze these data to generate a map of the currents.

The diagram below shows the movements of drifting buoys in the tropical Pacific Ocean during March-April 2009. The linear segments of each trajectory represent a one week displacement. 

Red paths show buoys with trailing drogues to 15-m depth; blue paths show undrogued buoys.

Notice the heads on the arrows showing direction of movement.

You will need to examine the maps of the web pages in this expedition and generalize your observations by drawing a few arrows on the maps in your handout, in order to show the direction of surface flow of the ocean in each region.

The heads of the arrows are a little subtle in this figure, but improve on the subsequent pages.

Also note that the length of the arrows signifies the distance traveled of the period of time in question (November 2010) -- this represent the speed of the current carrying the drifter. 

 

Map of Buoy Trajectories in Equatorial Pacific in October 2012

Let's next examine the North Pacific and South Pacific