SIO 210 Lecture 1: Introduction to ocean circulation.

Lynne Talley, September 26. 1996
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Reading and study questions

Reading:

Geography: Pickard and Emery, chapter 2 (skim - not too important)

Introductions to circulation: Tomczak and Godfrey, chap. 1 or Pickard and Emery, chap. 7.1

surface circulation: P&E figs. 7.9, 7.31, 7.41 or Tomczak and Godfrey maps in each chapter on different oceans or Ocean Circulation chapter 3 (very old, disreputable map of surface circulation)

Broecker, W.S., 1991. The great ocean conveyor. Oceanography, 4, 79-89.

Further reading

Gill text, sections 1.2 and 1.6
McLellan text, chapters 3.1-3.5, 4, 5

Other sources for viewgraphs (either the figure or data for the figure):

Barnier, B., L. Siefridt and P. Marchesiello, 1994. Thermal forcing for a global ocean circulation model using a three-year climatology of ECMWF analyses. J. Marine Systems, 6, 363-380. (net surface heat flux; gif plot data)

Gordon, A.L., 1986. Interocean exchange of thermocline water. J. Geophys. Res., 91, 5037-5046. 339-359. (source of popularized conveyor belt idea)

Hellerman, S. and M. Rosenstein, 1983. J. Phys. Oceanogr., 13, 1093-1104. (wind stress maps)

Hsiung, J., 1985. Estimates of global oceanic meridional heat transport. J. Phys. Oceanogr., 15, 1405-1413. (excellent net heat flux maps)

Levitus, S., 1982. Climatological atlas of the world ocean. NOAA Prof. Paper 13, 173 pp. (climatological data used for average property maps; source of data for gif plots)

Lynn, R.J. and J.L. Reid, 1968. Characteristics and circulation of deep and abyssal waters. Deep-Sea Res., 15, 577-598. (good reference with meridional vertical sections)

Reid, J.L., 1969. Sea-surface temperature, salinity, and density of the Pacific Ocean in summer and in winter. Deep-Sea Res., 16 (suppl), 214-224. (surface property maps)

Schmitt, R., P. Bogden, C. Dorman, 1989. Evaporation minus precipitation and density fluxes for the North Atlantic. J. Phys. Oceanogr., 19, 1208-1221.

Schmitz, W. J., 1995. On the interbasin-scale thermohaline circulation. Rev. Geophys., 33, 151-173. (recent updated conveyor belt ideas)

Worthington, L.V., 1981. The water masses of the world ocean: some results of a fine-scale census. In Evolution of Physical Oceanography, MIT Press, 42-69.

Other viewgraphs personal communications from L. Talley.

Study questions:

1. How much of the earth is covered with water? In what latitude ranges is the earth covered by water all the way around? What effect does the presence of continental boundaries at most latitudes have on the circulation? What happens where there is no continental boundary?

2. What are the forcing mechanisms for the ocean?

3. What are the usual flows associated with subtropical and subpolar gyres? Which has low pressure in the center? Which way do they circulate in both hemispheres and why? Name the major currents associated with these gyre circulations for each ocean. Name a major southern hemisphere current which has no northern hemisphere counterpart.

4. What are typical horizontal velocities for the ocean? What are typical vertical velocities?

5. How deep is the ocean on average? How does this compare with the average zonal dimension of the three major oceans? What effect might this difference between the horizontal and vertical dimensions have on the relative magnitude of flow in the horizontal and vertical?

Study calculations:

1. What is the volume transport in m3 /sec of a current which is flowing at 10 cm/sec over a width of 200 km and a depth of 5000m?

2. If 10 x 10e6 m3 /sec of water upwells from one deep layer into the overlying layer over the area of the North Atlantic, what is the approximate vertical velocity associated with it? Assume that very crudely the North Atlantic is 6000 km by 6000 km.