Wordsmith.org: the magic of words

Wordsmith Talk

About Us | What's New | Search | Site Map | Contact Us  

Page 4 of 6 < 1 2 3 4 5 6 >
Topic Options
#66708 - 04/24/02 12:18 AM Re: Who lives the furthest from the coast?
stales Offline
old hand

Registered: 11/13/00
Posts: 866
Loc: Perth, Western Australia
Sorry Jazzo - the Southern Ocean is there.

The Pacific, Atlantic and Indian are merely its northern extensions.

stales


Top
#66709 - 04/24/02 10:33 AM Re: Who lives the furthest from the coast?
Bean Offline
old hand

Registered: 01/18/01
Posts: 1156
Poppycock! Since when is there a "Southern Ocean"? All that down there is the combination of the Indian, Pacific and Atlantic. The only circumpolar "ocean" is the Arctic. not that the oceans are really made of anything different anyway . . .

Careful Jazzo, there are oceanographers aBoard! The "Southern Ocean" is not one of the Big 3 but it is important in an oceanographic sense. The number one reason (which brings me to your second statment) is that it is the only circumpolar ocean. The Arctic has some little problems with that where LAND is in the way - preventing a current from running in a circle all around the world at a given latitude (called a zonal current). On the other hand, with the way the Southern Hemisphere turned out, you actually have a zonal current running in a circle around the South Pole between about 40S and 70S. It's called - wait for it - the Antarctic Circumpolar Current! (South America forces it to narrow a bit but there's still plenty of room for a zonal current.)

And of course they are all made of different things! Different temperatures and different salinities. They even have names for the different water types. The different water types are important for global ocean circulation. And global ocean circulation is important for many people aBoard, for example, because the Gulf Stream keeps the Eastern US and England warmer than they really should be in the winter (given their latitudes).

Anyway, there are noticeable "fronts" between water types in the ocean (just like between air masses on weather maps). Here is some explanation from the most boring book ever written (Descriptive Physical Oceanography by Pickard and Emery)

"Going north from the Antarctic continent the average sea surface temperature increases slowly until a region is reached where a relatively rapid increase of 2 to 3K [Kelvin] occurs. The surface water from south of this region is moving north and sinks when it reaches the region, continuing north below the surface. At the surface therefore the water is converging to this region which...is now called the Antarctic Polar Front (APF)...Continuing north from this APF the temperature rises slowly to a second region where it rises rapidly by about 4K and the salinity by about 0.5 [PSU]. This is referred to as the Subtropical Convergence."

And on it goes like that!

Some ocean factoids so you realize not all seawater is the same:
(1) The mediterranean has the most saline water.
(2) The coldest, densest water on earth (Antarctic Bottom Water) is formed near the coastal shelf of Antarctica.
(3) The Pacific Ocean has slightly less saline water than the Atlantic Ocean.
(4) The second-coldest, densest water is formed in the Labrador Sea or the Greenland-Iceland-Norwegian (usually called the GIN ) seas and is called North Atlantic Deep Water.
(5) There is a so-called "conveyor belt" of ocean circulation in which water moves very slowly all over the world called the Thermohaline Circulation because the driving forces are heat (thermo) and salt (haline). Roughly, water sinks in the Southern Ocean, moves northward in the Pacific and rises near the west coast of North America, continues along the surface north of Australia, south of Africa, joins up with the Antarctic Circumpolar Current but also moves north along the east coast of South and North America, including the Gulf Stream, sinks near Newfoundland and Greenland, and moves along the bottom back to the Southern Ocean.

Man, you guys have been giving my oceanographic muscles a workout this week! Isn't it just the neatest subject?

Edit: Here's a link to a "cartoon" of thermohaline circulation (it's, of course, far more complicated than this looks). http://www.clivar.org/publications/other_pubs/clivar_transp/pdf_files/av_d3_992.pdf

Top
#66710 - 04/24/02 11:00 AM Re: Who lives the furthest from the coast?
of troy Offline
Carpal Tunnel

Registered: 10/17/00
Posts: 5400
Loc: rego park
Aren't there also Gyers? (that word is way to short but i can just barely remember the word..)

the one i am thinking of, is giant current of water, that sort of circles.. it move from the Aleutians islands in alaska, down the alaskan pan haddle, continues down the coast all the way to SF, moves out in a giant cicle, till it meets up again with the Aleutians islands ..

Its the current of water that helps make seattle so raining, and SF so foggy, and make the pacific water so cold at the coast line, compared to the Atlantic.

the gulf stream isn't quite a circle (but the atlantic is also not as big an ocean.) And it brings warm tropical waters up the US east coast, Turn just south of NY (but in the summer, scuba divers can find tropical fish off NYC beaches, brought there by the current.) and it make the east coast warmer.. it also bring coconut palm seeds to the coast of ireland, were they sprout, an live for 20 to 30 years, before a cold winter kills them off..

there is an other one of these currents off the coast of peru, all the way out to the galapagoes islands.. and i think there are more, in asia, but... well its far away, and i'm not sure..

and you can see the gulf stream waters.. on a clear calm day, you can actually see different shades of green in the water.. (best from the air) but even when swimming, you can see an eddy of warm water in the ocean.. and feel it as is swirls by!

_________________________
my other obsession

Top
#66711 - 04/24/02 11:54 AM Re: Who lives the furthest from the coast?
Bean Offline
old hand

Registered: 01/18/01
Posts: 1156
Yup, helen, you're thinking of "gyres" probably (close on the the spelling!) Those are surface currents and occur on a different timescale than the thermohaline circulation, which occurs on a "millenial" timescale. (And before you ask how on earth they figured that out - because I asked that too - they can track the circulation by observing different chemicals in the water that indicate where it originated.) There are both western and eastern boundary currents, and they are the ones you refer to. (In this case, west and east refer to the ocean basin, not the adjacent continent.) Because of the way the world turns, western boundary currents are more intense than the eastern ones, more closely constrained to the coastline. Western boundary currents move poleward and eastern boundary currents move equatorward. They are:

Western Boundary Currents: Gulf Stream (North Atlantic), Kuroshio (North Pacific), Agulhas (South Indian), Brazil (South Atlantic), East Australia (South Pacific)
Eastern Boundary Currents: California (North Pacific), Canary (North Atlantic), Peru (South Pacific), Benguela (South Atlantic), West Australia (South Indian)

There are also Equatorial Currents: the North and South Equatorial Currents (both going E-W), the Equatorial Counter Current (between them, going W-E), and the Equatorial Undercurrent (beneath them, W-E).

As for the cold upwelling (water from the deeper part of the ocean being drawn to the surface) during the summer on the west coast of NA, that is apparently caused by wind. The primary wind direction during summer in that region is north to south. When wind blows across the water, the net water transport is 90 to the right of the wind direction (Northern Hemisphere) rather than along the wind direction, as you might expect (creepy but true, blame Mr. Ekman for discovering that!) So the north-south wind causes water to move from east to west, and cold water comes up from the deep to take its place as it moves offshore.


Top
#66712 - 04/24/02 12:11 PM Re: Who lives the furthest from the coast?
of troy Offline
Carpal Tunnel

Registered: 10/17/00
Posts: 5400
Loc: rego park
i guess swimming in the ocean is a good learning experience!

Swimming in salt water, with waves, is the very best way to swim-- it might also be the most dangerous. two of my cousins and a neighbor (all three good swimmers) have drown in the atlantic. (cousins back in 1969, neighbor, 4 years ago.)

_________________________
my other obsession

Top
#66713 - 04/24/02 12:35 PM Re: Who lives the furthest from the coast?
Jackie Offline

Carpal Tunnel

Registered: 03/15/00
Posts: 11610
Loc: Louisville, Kentucky
Wow, Bean, this is so cool--thank you! [impressed as all get-out e]
2) The coldest, densest water on earth (Antarctic Bottom Water) is formed near the coastal shelf of Antarctica.
Does anyone know if this affects submarine performance enough that the crews get special training to go here?



Top
#66714 - 04/24/02 12:40 PM Re: Who lives the furthest from the coast?
Bean Offline
old hand

Registered: 01/18/01
Posts: 1156
Does anyone know if this affects submarine performance enough that the crews get special training to go here?

I don't know about that but I do know another factoid: Apparently Australian ocean research vessels (or is it navy? stales?) aren't allowed to go further south than a certain latitude because that's the point at which the water becomes cold very suddenly (possibly one of the fronts mentioned above), and the hulls of their boats will crack. How's that for cool?




Top
#66715 - 04/24/02 01:05 PM Re: Who lives the furthest from the coast?
Jazzoctopus Offline
old hand

Registered: 07/03/00
Posts: 1094
Loc: Cincinnati & Loveland, Ohio, U...
The "Southern Ocean" is not one of the Big 3 but it is important in an oceanographic sense.

Well, color me naive, I've never seen a map with the Southern Ocean labelled. Someone's hiding things from us.

Seems like it would be just as big, or bigger than the Arctic Ocean, so why wouldn't it be a major one? Are there any other "oceans" that have been hiding from me? And also, are the noticable boundaries between the oceans, so that you can actually tell in a boat, that you've gone from one to another?


Top
#66716 - 04/24/02 01:27 PM Re: Who lives the furthest from the coast?
Capital Kiwi Offline
Carpal Tunnel

Registered: 11/13/00
Posts: 3146
Loc: Northamptonshire, England
Apparently Australian ocean research vessels (or is it navy? stales?) aren't allowed to go further south than a certain latitude because that's the point at which the water becomes cold very suddenly (possibly one of the fronts mentioned above), and the hulls of their boats will crack.

And that point was just off Fremantle for Kookaburra II ...

_________________________
The idiot also known as Capfka ...

Top
#66717 - 04/24/02 01:58 PM Re: Who lives the furthest from the coast?
of troy Offline
Carpal Tunnel

Registered: 10/17/00
Posts: 5400
Loc: rego park
are the noticable boundaries between the oceans, so that you can actually tell in a boat, that you've gone from one to another?

from what i have read, the answers is, sometimes yes..
that why there is a indian ocean, and not just a very big south pacific! at some point the water changed and sailor decided it was different enough..

and at places like the straits of magelean, or cape of good hope, (S. africa) the change is oceans is also marked by rough seas, as the different tempuratures, and densities merge.

_________________________
my other obsession

Top
Page 4 of 6 < 1 2 3 4 5 6 >

Moderator:  Jackie 
Forum Stats
8769 Members
16 Forums
13814 Topics
216150 Posts

Max Online: 3341 @ 12/09/11 02:15 PM
Newest Members
Rupak, DeathCake, malagachica, Jamie, pr3sedentedonut
8769 Registered Users
Who's Online
0 registered (), 43 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Top Posters (30 Days)
endymion6 105
LukeJavan8 104
wofahulicodoc 98
AlimaeHP 14
Tromboniator 11
BranShea 2
tsuwm 2
Storymom 1
sleeper54 1
wsieber 1
Top Posters
wwh 13858
Faldage 13803
Jackie 11610
tsuwm 10525
Buffalo Shrdlu 7210
LukeJavan8 6784
AnnaStrophic 6511
Wordwind 6296
of troy 5400
BranShea 5284

Disclaimer: Wordsmith.org is not responsible for views expressed on this site. Use of this forum is at your own risk and liability - you agree to hold Wordsmith.org and its associates harmless as a condition of using it.

Home | Today's Word | Yesterday's Word | Subscribe | FAQ | Archives | Search | Feedback
Wordsmith Talk | Wordsmith Chat

© 2014 Wordsmith