SIO 210: Fall 2002

Thermohaline Circulation I: Basic Concepts

Pickard and Emery, Descriptive Physical Oceanography: An Introduction Section 5.3
The Labrador Sea Deep Convection Experiment, Bulletin of the American Meteorological Society: Vol. 79, No. 10, pp. 2033-2058. [Online]
Stommel, H., Arons, A.B., Faller, A.J., Some examples of stationary planetary flow patterns in bounded basins.Tellus, v.10:2, pp. 179-187, May 1958 [electronic reserves]

What are the four terms of heat exchange between the ocean and atmosphere? Which term always heats the ocean? Which terms can change sign depending on local conditions? What is the dominant mechanism for cooling the ocean?
What are the effects of cloud cover on the heating of the ocean?
What are typical values for evaporation and precipitation over the ocean?
What physical conditions are typically necessary for open-ocean convection? Deep water formation on the shelf?
What are the key features of deep water circulation expected from application of basic fluid dynamics?

A 50m thick water column is observed to cool by 3^oC over the course of 40 days. Assuming all the cooling is due to local heat loss to the atmosphere, what is the mean heat flux (in W/m²) across the air-sea interface? [Heat capacity of seawater c_p = 3985 J/(kg ^oC)]. During this time the water also freshens from 35.1 to 34.6 psu despite a calculated evaporative loss of 4 mm/day. What is the net rainfall (in cm) over the 40 days?
If the total global production of deep water is 30 Sv, what is the mean upwelling velocity of the abyssal ocean? How does this compare with the magnitude of Ekman pumping at the ocean surface?

Last modified: Wed Nov 13 16:29:45 2002