Equatorial ocean waters have high surface temperatures and low surface density, while high latitude waters are cold with high surface density. The Subtropical Convergence accounts for higher average surface densities in the Southern Hemisphere due to the mixing of cold, dense waters with warmer waters. Thermohaline circulation is controlled by temperature and salinity, which influence water density.
48) The surface temperature and surface density of ocean waters in equatorial regions tend to be higher and lower, respectively, due to intense solar heating.
Warm water is less dense and therefore does not sink.
49) In contrast, at high latitudes, the surface temperature of ocean waters is cold and the surface density is high due to cooler atmospheric temperatures and the fact that cold water is more dense.
This higher density leads to sinking of water, which contributes to thermohaline circulation.
50) One reason higher average surface densities are found in the Southern Hemisphere is due to the Subtropical Convergence.
Here, the cold, dense waters of the Southern Ocean sink below the warmer waters of the Pacific, Atlantic, and Indian Oceans, causing upwelling and mixing that increase productivity for organisms such as phytoplankton and krill.
51) The two controlling factors in thermohaline circulation are temperature and salinity, which collectively affect the density of seawater.
Changes in these factors drive the movement of ocean currents and the overall circulation patterns that redistribute heat globally.
Question:
48) Describe the surface temperature and surface density of ocean waters in equatorial regions.
49) Describe the surface temperature and surface density at high latitudes. 50) What is the reason for the fact that higher average surface densities are found in the Southern Hemisphere? (Review the diagram showing the surface currents you examined earlier in the lab and look at the southern hemisphere)
51) What are the two controlling factors in thermohaline circulation on the planet?