Although I never took an oceanography class, Fred Larsen asked in 1983 if I could teach intro-level Oceanography at Norwich, to which I instantly answered yes. It was a physical oceanography course and I assumed it couldn’t be much different from marine geology (thank you Dr. Parks). It turns out that it’s one of my favorite courses. Labs are particularly exciting, with a highlight each winter being our Sunset Lake study – three labs for each section on the ice to measure depths, record temperature-depth profiles, and collect cores for analysis during the following two weeks.

Another lab focuses on turbidity flows, using a tank built by Fred (Fred’s Sed Bed). The upper video illustrates behavior of a turbidity flow in a fluid of constant density. We use the same tank and build a two-layer “ocean” with ice-cold, high salinity blue water on the bottom, and warm fresh yellow water on the top (lower video). The turbid slug of water in this case slides down the “delta front” and initiates an internal wave that doesn’t disturb the surface in the least. A small fraction of turbid water has a density between those of the two layers and shoots out behind the wave as a tongue between the layers.

[powerpress url=”http://voices.norwich.edu/davewesterman/files/2010/10/Turbidite-in-clear-water.m4v”]

[powerpress url=”http://voices.norwich.edu/davewesterman/files/2010/10/Turbidity-flow-generating-internal-wave.m4v”]

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