Antarctica and the THC. Seasonal pulses ! ! !

Derek · Antarctica and the THC. Seasonal pulses ! ! !

Hi All,
I'd like to ask an open question.
The Thermohaline Circulation, has there been any "improvement" in our understanding of it in recent times.
I've seen "old" pictures like, (1991 for goodness sake..)

which do not seem any improvement on far, far older pictures.

I have heard vaguely that the Gulf Stream is thought to have seasonal fluctuations, presumably because of spring melt of Arctic sea ice,
is this "understood" rather than merely observed.

The THC diagrams I've seen, appear to be bit "primative", is there anything better. Just a pointer would be nice,
but if anyone knows more, I'd be grateful if you'd share some more upto date knowledge,
or good links.

There are two things that (mainly) sort of puzzle me at present about the explanations of the THC I've read so far.

1) There does not seem to be any seasonal fluctuations incorporated in the explanations.
Antarctica doubles in area due to sea ice in winter, this melts "back" the following spring.
Surely an area equivalent to 1 and a half times the size of the USA melting annually must have quite an effect on the THC,
a seasonal pulse or pulses, or different "regimes" would seem a reasonable suggestion.

2) Many will have seen the film clips of killer whales "beaching" themselves to catch seal pups on the West coast of South America.
This is a "common" occrence, therefore the deep water upwelling that
feed the plankton, that feed the anchovies, that feed the seals, that feed the killer whales, is it a "regular" occurance as well.
Seal breeding patterns would seem to suggest so.
None of the THC explanations I've seen show such a deep water upwelling along the West coast of South America...
Maybe it is wind driven overturning, I do not know, but any pointers, or help would be greatly appreciated.

Incidentally I'LL consider any / all points of view, mainstream or otherwise.
Then I'll consider for myself, as I hope we all do anyway.

billiards

I must first say that my oceanography is very rusty, I did do very well in my oceanography course back at uni, but that was about two years ago now. One thing I remember about the THC, though, is that it is not meant to be a very accurate description of ocean circulation. Rather, it is intended to be an extremely simple, rough guide to ocean circulation which is easily committed to memory. If you were to look at local currents you would see far more complexity, and furthermore, these complexities will often be seasonally dependent.

Derek

The seasonal variability of the THC.
It is very difficult to imagine the world's oceans as "one" with the normal map projections.
If viewed from Antarctica, remembering the circum polar current, and seasonal sea ice variations
would it be easier to visualise the possible seasonal pulse Antarctica could have on the THC.

I was pondering this the other day whilst peeling a tangerine.
This gave me an idea. Draw the world's oceans on a tangerine,
and then peel it so you could lay them flat.
Would it look something like,

You can see how I got to this here,
http://s53.photobucket.com/albums...kJohn_photos/Tangerine%20project/