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It has become clear in recent years that a fairly strong analogy exists between the circulation of the ocean and that of the atmosphere. The programme begins by laying the foundation of the analogy... by introducing the idea of the equivalents of weather and climate in the ocean, and a brief introduction to MODE (Mid Ocean Dynamics Experiment) is given by Walter Munk. Sandra Smith gives a resume of some of the classical 'climatic' topics in ocean circulation - namely surface and bottom circulation, baroclinic geostrophic flow and intensification of western boundary currents - using animation and models. Coming back to MODE, the programme uses film shot during the main experiment to show the deployment of swallow and SOFAR floats, and deep ocean current meters. The experiment succeeded in discovering ocean weather and an animation showing the development of a 'storm' or eddy as observed, during MODE is included. Peter Rhines talks about the role of the computer in simulating these eddies to help further our understanding, but Walter Munk concludes on the note that we have a long way to go before we can claim to fully understand them.
Metadata describing this Open University video programme
Module code and title: S334, Oceanography
Item code: S334; 06
First transmission date: 18-05-1978
Published: 1978
Rights Statement:
Restrictions on use:
Duration: 00:24:00
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Producer: John Stratford
Contributors: Walter Munk; Sandie Smith
Publisher: BBC Open University
Keyword(s): Circulation; Computer model; Current meter; Eulerian analysis; Geostrophic balance; Isobars; MODE (Mid Ocean Dynamics Experiment); Swallow float
Footage description: Sandra Smith and Walter Munk introduce the programme. Sandra Smith, with the aid of animated maps of the world and of Europe, points out the difference between long term overall wind directions which control climate and short term fluctuations which determine weather. She then introduces a possible analogy for the world's ocean currents. Shots of a map of the world showing ocean currents. Walter Munk joins the discussion. Sandra Smith, pointing to maps of the world's oceans, discusses the difference between surface and ocean bottom circulation. Sandra Smith goes on to explain how, by taking density, temperature and salinity measurements oceanographers were able to determine long term water movements in the deep ocean. An animated cross section diagram of the Atlantic showing isotherms, isopycnals and isobars illustrate her points. Using a globe and a pendulum, Sandra Smith demonstrates vorticity, the effect of the earth's rotation on ocean currents. Walter Munk and Sandra Smith describe, briefly how the experiments by John Swallow in the 1960's changed this picture of ocean currents. Sandra Smith (mostly voice over film) explains how readings of ocean currents are taken. Film of recording floats being prepared and launched. Film shots of deep sea current meters being prepared and launched. Commentary by Sandra Smith explains how they work. An animated diagram of the area in which one of these probes operates helps to illustrate the principles by which they work. Using a contoured map (partly animated) of the MODE area, Sandra Smith sums up how the data collected in this project builds up a picture of the ocean analogous to an atmospheric weather map. Peter Rhines, with the aid of an animated map, explains how deep ocean eddies were discovered after project MODE was finished. Walter Munk speculates on the possible causes of these eddies. Peter Rhines shows a computer animation of part of the Gulf Stream. This illustrates a possible mechanism for the formation of surface and deep ocean eddies. Walter Munk sums up the programme.
Master spool number: 6HT/72600
Production number: 00525_1298
Videofinder number: 877
Available to public: no