Natural Science Forum / Earth Science / Oceanography / January 2007

of the sky.

If I remember correctly, the planet will easily fit into the famous red
spot on Jupiter.

There is a gyre on earth that is some 2000 miles across -if I remember
something I read a long time ago. It is composed of the surface water
several hundred feet deep, that washes along the coast of the North
American continent to about 55 to 60 degrees north, then heads east to
Norway and Britain.

gets to the tropics where it heads west once again to drive up the
coast of some of the Americas.

With a disk some 8000 miles in diameter and a gyre of that size (the
North Atlantic Basin) the earth has a proportionately larger optical
phenomenon than that of Jupiter's 3 or 4 hundred year old storm.

Does anyone know what causes either?

Some people (one hesitates to call one's peers sheep, as that puts
oneself at a disadvantage) consider the event on the earth is caused by
the lack of air pressure.

(How a Low can have a force is beyond me but that is by the by.)

Perhaps more lucid experts have been able to a.ses the physics of
something a little more distant.

If so, is there a link to the effort?

It would be nice to have any proffered explanation deal with the
physics rather than the observation. I know that somewhere between Adam
and Pasteur there was a great darkness about diseases that due to
ignorance, called for the treatment of the symptoms rather than their
cause; it would be good if such an abuse of facts were avoided here.)

*That it can't be air pressure is seen by the fact that on the equator
there exists something akin to the jet stream. A narrow current of
water flowing straight and true, the other way.

The ocean flow in the N Atlantic basin is some 30 million cubic metres
of water per second through the straights of Florida and 80 million
past Cape Hatteras. (According to the 1998 Encyclopedia Britannica)

Also from the Enc Brit:

Movement of water through the oceans is slowed by friction, with
surrounding fluid moving at a different velocity. A faster-moving fluid
layer tends to drag along a slower-moving layer, and a slower-moving
layer will tend to reduce the speed of a faster-moving layer.

This momentum transfer between the layers is referred to as frictional
forces

The momentum transfer is a product of turbulence that moves kinetic
energy to smaller scales until at the centimetre scale it is dissipated
as heat. The wind blowing over the sea surface transfers momentum to
the water. This frictional force at the sea surface (i.e., the wind
stress) produces the wind-driven circulation.

Currents moving along the ocean floor and the sides of the ocean also
are subject to the influence of boundary-layer friction. The motionless
ocean floor removes momentum from the circulation of the ocean waters.

But:

in fluid mechanics, thin layer of a flowing gas or liquid in contact
with a surface such as that of an airplane wing or of the inside of a
pipe. The fluid in the boundary layer is subjected to shearing forces.
A range of velocities exists across the boundary layer from maximum to
zero, provided the fluid is in contact with the surface.

[How much more so if the fluids are miscible? It stops becoming fluid
mechanics there doesn't it and branches off into hydrostatics. Or is
that pneumodynamics?]

The peculiar flow in boundary layers can be treated in a simpler way
than the flow in the free stream farther from the surface.

Boundary layers are thinner at the leading edge of an aircraft wing and
thicker toward the trailing edge. The flow in such boundary layers is
generally laminar at the leading or upstream portion and turbulent in
the trailing or downstream portion. See also laminar flow; turbulent
flow.

[There won't be much kinetic energy imparted to the sea's surface
where: "..the flow in such boundary layers is ... laminar..." will
there? Water is considered a perfect fluid. It's viscosity is such that
in a cylinder, it will remain -or tend to remain, stationary if the
cylinder containing it is rotated. How much less will the force of air
effect it?]