Talley, L. D., 2001. Ocean Circulation. In Encyclopedia of Global Environmental Change, vol. 1, T. Munn editor, John Wiley and Sons. (also in electronic reserves)
Study questions:
1. What are the common elements of the surface
circulation found in the N. Pacific and N. Atlantic?
2. Name the major surface western boundary currents in these two oceans, indicate which way they flow and what gyre circulation they are a part of. What are typical maximum velocities and dynamic height differences for these boundary currents?
3. What horizontal and vertical structure is typical of the subtropical gyre?
4. How deep are the western boundary currents?
5. How deep is the typical wind-driven gyre, excluding the western boundary current?
6. In which parts of the ocean is it currently assumed that the Sverdrup balance is approximately correct? Where is it clearly incorrect?
7. How deep is the directly wind-driven layer? How deep is the surface mixed layer in the North Pacific? How deep is it in the North Atlantic? How does this penetration depth differ between the subtropical and subpolar gyres?
Study calculations
1. If the Kuroshio Extension velocity is 10 cm/sec averaged
from top to bottom, and the current
width is 100km, assuming a depth of 5 km, what is its volume
transport? Express transport in Sverdrups. What is its
approximate mass transport assuming a constant density?
2. A steady wind field is blowing on a rectangular ocean basin 8000 km wide. At 25oN, the wind blows from the east at a speed of u10=8 m/s. At 40oN, the wind blows from the west at a speed of u10=8 m/s. What is the rate of wind-driven Ekman mass convergence between 25oN and 40oN (in kg/s)? What is the average Ekman pumping (in cm/s) between 25oN and 40oN? [1 degree of latitude = 111.12 km].