Exercise - Thermo-Haline Circulation
T-S plot
Consider the T-S plot, made from the south to north Pacific.
Consider the southern-most TS profile. There are three endpoints representing the core waters - identify them.
What direction does the deep water move, and how does it change as it moves?
As you move along the path of the water, why does the water at about 5 degrees C get saltier and then fresher again?
This plot is also available in
- higher resolution (390 Kb).
- full resolution (5 Mb).
Inverse modelling
Suppose we have a basin that is 1000 km wide at each end, running north to south, and 3000 km long. We want to constrain the water denser than an isopycnal that comprises the top of the volume.
At the south end: Thickness of the layer encompassed by the isopycnal is 2500 m, the average temperature in the section beneath the isopycnal is T=3.2 deg C, the average salinity, S=33 psu, and the average speed through the section is V=0.02 m/s (positive to the north)
North end: Thickness = 2200 m T= 3.3 deg C, S = 33.105 psu, V=??
If the average temperature at the bounding isopycnal is 7 deg C, what is the velocity out the north end and the velocity out the top of the basin? (Hint conserve heat, or more directly temperature).
What must the average salinity be at the top of the surface?