In today's expedition, you will be looking at the flow of the surfce waters of the ocean, called surface circulation, by tracking surface buoys with satellites in the major oceans.
Once again, you will be the scientist, using floating and drifting buoys out in the ocean to determine the flow of ocean and in the end compare it to a very simplified, generalized diagram of the surface flow in the ocean.
By analyzing the drifting buoys, you will see how scientists determine the flow of the surface circulation, second you will see how the data are analyzed, going from the raw drifter motion each month to an average or mean velocity of the drifters per year, for example, one year, to get a generalized view of circulation and then to a very simple diagram for the layperson that does not exhibit some of the fascinating complications that we see in the data.
We will end with an examination of the boundary currents, along the edges of the ocean, on either the western side of the ocean, called western boundary currents, or the eastern side, called eastern boundary currents, for example the California current as an eastern boundary currents, which brings cold water south from the subpolar regions, so eastern boundary currents tend to be slow and carry cold water.
Western boundary currents, which are on the western side of the ocean basin, like the Gulf Stream off the U.S., and the Kuroshio, off Japan, move away from the equator, carrying warm water and they are also intensified due to the rotation of the earth and are fast.-moving.
The speed of the current is realted to the rotation of the earth, something called vorticity, and the piling up of water on the western side of the basin, which then has to flow back eastward.
Let's now look at the flow of the surface waters of the ocean.
Objective: Students will use a scientific approach to study a problem of the Earth and environment, specifically the global flow of surface waters in the ocean basin.
Let's first review where we left off last time with the ending page from the previous expedition -- your worksheet begins on the next web page.
Remember the previous map of the global wind patterns?
The directions of the winds form big circular loops with the
major circular loop in the northern hemisphere rotating in a clockwise direction and in
the southern hemisphere, in a counterclockwise direction.
We can trace the direction of surface currents below these
winds in many ways, for example with current meters attached to the seafloor or with floats that are carried with
the currents, just like the Nike tennis shows and rubber that you learned about in the previous expedition
Here are "high tech" methods to determine the
Listen to the brief Ocean Report again: Transcript:
These drifters phone home -- they are drifting buoys used for ocean research. These drifters go with the flow and send messages home via satellite.
I'm Peter Benchley and this is the Ocean Report.
The U.S. National Oceanic and Atmospheric Administration, or NOAA, uses drifting buoys, called drifters, to study ocean currents. Drifters have parachuted out of airplanes into the ocean around Antarctica and have been placed in the path of hurricanes.
A little closer to home, are a set of moored buoys. NOAA uses them to predict weather patterns by tracking ocean conditions. These buoys are found all along the coast of the United States and in the Great Lakes. They measure things like ocean temperature, wind speed and wave height.
A NOAA website has picture of the buoys, which we will see in a later expediton, and let's you see the wind and wave measurements taken by the buoys, and students in some schools are adopting a buoy to watch the weather and ocean conditions. The website is also great place for answers to ocean questions, like what happens during a hurricane.
If you want to hang around with some drifters go to www.ndbc.noaa.gov (not now as we will go there in a subsequent expeditions).
The Ocean Report is a project of the Pew Charitable Trust