at the average salinity of the ocean, it is right around 4C (plug and chug into inverted mile's calculator and you can find out exactly where).Originally Posted by archman
i'm typically referring to water below the thermocline, which is always below 4C... it slowly keeps dropping. however, the depth at which the thermocline occurs varies for certain.Deep-sea temperatures vary quite a bit, around six degrees or so. Sometime it's above 4C, more often it's below it.
without a true model of all the ocean, i.e. sea floor depth, salinity, etc., all you can really do is approximate based on averages. i.e. we know about 70% of the oceans' water is below the thermocline, which means <4C. we can also pick some average value for salinity. otherwise, massive finite element analyses would be required to figure out what really would happen.
the point then, is to show averages and run the numbers from there. everybody has to do the same thing simply due to the sheer complexity of the problem.