148
The Last Resource
'
currents do exist but, apart from locally rapid movements, they seem
slow and weak compared to their surface counterparts. For instance,
water moves along the bottom of the Atlantic Ocean from north to
southat an average speed of a thousandth of a knot compared with
the Gulf Stream’s speed of four to ve knots.
_
.
In general, the surface currents for—m loops called
each one
almost the full Width of the ocean. In the Northern Hemisphere
there are two—One in the Atlantic and the other in the Pacic—
rotating sloWl‘y in a clockwise directi0n. South of the equator there
are three anti—clôckWise gyres—in
Atlantic, Indian and Pacic
a fourth one which surrounds the Antarctic continent.
These currents correspond roughly to the prevailing winds—the
Westerliès and the Trade Winds—'——indicang the part these wind
systems play ….in creating them. They do not Correspond exactly,
because the” Earth…‘s rotation applies a force, the Coriolis force, on
the movingwater. This force, Which increases with the distance
from the Equator, deects the…currents to
in the Northern
Hemisphere and to the:left in the
NOrth‘èm and southern
gyres are separated by an Equatorial Counter—cürrent which runs in
the opposite direction
“ow of these parts of the
gyres. In the equatoal regi0n the winds are solig‘ht and variable
that it is called the
and the lack of any preVailing, driving
force permits water ‘piled up’ against the shores
the westernsides
of the oceans to ow back—asa;counter—Current.
…»
g ,
:
’
_
Nothing like as much is known,about the.deep-oceanÎcurrents as:
the surface ones. According to one theor‘etical_hmdel, proposed by
the American oceanographer Dr Henry Stommel,cold water found
in the ocean deepsfarises from',twOpr1ncrpalsources—the
Sea in the Antarctic andthe extreme
Thé cold polar
run, as deep counter—currents
the
weSternsides of the
eastwardsæas they go,.
_
TheAtlanti‘cä ,0œan‘hàs5b‘œn ?th6'mostintenSelÿ s'tudied.f‘G@ld North
be Ïtraced. as a“, distinct mass—throughout the
Atlantic,fOcean {but-in the South even colderfAntarctic Water liesIn the Southern He$phere both—Arctic and Antarcticwaters
by: the Antarctic Intermediate : Water f0rmed =
water meets warmer ghter water*fr“om equatorial.
regions and sinks
it. Theserandî ôther deep-Waters «like the
denSeï
0wing out of the
be detected…
by their;
such as temperature,
The Last Resource
'
currents do exist but, apart from locally rapid movements, they seem
slow and weak compared to their surface counterparts. For instance,
water moves along the bottom of the Atlantic Ocean from north to
southat an average speed of a thousandth of a knot compared with
the Gulf Stream’s speed of four to ve knots.
_
.
In general, the surface currents for—m loops called
each one
almost the full Width of the ocean. In the Northern Hemisphere
there are two—One in the Atlantic and the other in the Pacic—
rotating sloWl‘y in a clockwise directi0n. South of the equator there
are three anti—clôckWise gyres—in
Atlantic, Indian and Pacic
a fourth one which surrounds the Antarctic continent.
These currents correspond roughly to the prevailing winds—the
Westerliès and the Trade Winds—'——indicang the part these wind
systems play ….in creating them. They do not Correspond exactly,
because the” Earth…‘s rotation applies a force, the Coriolis force, on
the movingwater. This force, Which increases with the distance
from the Equator, deects the…currents to
in the Northern
Hemisphere and to the:left in the
NOrth‘èm and southern
gyres are separated by an Equatorial Counter—cürrent which runs in
the opposite direction
“ow of these parts of the
gyres. In the equatoal regi0n the winds are solig‘ht and variable
that it is called the
and the lack of any preVailing, driving
force permits water ‘piled up’ against the shores
the westernsides
of the oceans to ow back—asa;counter—Current.
…»
g ,
:
’
_
Nothing like as much is known,about the.deep-oceanÎcurrents as:
the surface ones. According to one theor‘etical_hmdel, proposed by
the American oceanographer Dr Henry Stommel,cold water found
in the ocean deepsfarises from',twOpr1ncrpalsources—the
Sea in the Antarctic andthe extreme
Thé cold polar
run, as deep counter—currents
the
weSternsides of the
eastwardsæas they go,.
_
TheAtlanti‘cä ,0œan‘hàs5b‘œn ?th6'mostintenSelÿ s'tudied.f‘G@ld North
be Ïtraced. as a“, distinct mass—throughout the
Atlantic,fOcean {but-in the South even colderfAntarctic Water liesIn the Southern He$phere both—Arctic and Antarcticwaters
by: the Antarctic Intermediate : Water f0rmed =
water meets warmer ghter water*fr“om equatorial.
regions and sinks
it. Theserandî ôther deep-Waters «like the
denSeï
0wing out of the
be detected…
by their;
such as temperature,