On 28 m=E4rts, 00:09, Rich Rostrom <rrostrom.21stcent...@[EMAIL PROTECTED]
> wrote:
> Crown-Horned Snorkack <chornedsnork...@[EMAIL PROTECTED]
> wrote:
> >However, if he reversed the rotation of Earth (which would have solved
> >his immediate problem, that of preventing the moon from moving on),
> >the centrifugal forces would be unchanged.
>
> >The Coriolis forces, however...
>
> That's an interesting point.
>
> One could argue that "the Earth" includes its
> atmosphere, hydrosphere, and other loose change,
> and that all of this would stop (or reverse)
> as well. But the indirect consequences of
> rotation couldn't very well change, too.
>
> Coriolis force is the most obvious.
>
> >If Coriolis forces instantly change sign, how long does it take for
> >trades and westerlies to overcome the inertia of moving air, and
> >reverse? What about the cyclones in being - does the changed
> >geostrophic force and the inertia of the rotation cause them to fill
> >and invert into anticyclones? What about ocean currents - how long
> >will the Gulf Stream need to reverse?
>
> The effect would be gradual. All the existing
> cyclonic vortexes would continue to spin for a
> while, then run down, and eventually spin up
> in the other direction (or be replaced by new
> opposite vortexes).
>
Essentially, a cyclone has the potential energy of the lack of air,
kinetic energy of moving air and the momentum of the moving air. The
reason why a cyclone does not fill is that Coriolis force prevents air
from moving inwards.
If you reverse the Coriolis force, it will force air inwards (which
the low pressure was already doing).
> The very-high-inertia vortexes (such as the
> oceanic currents) could persist for decades,
> till exhausted by friction.
>
> >As for tides, reversing the rotation of Earth would change the tidal
> >period from 12 hours 25 minutes to 11 hours 35 minutes. A minor
> >change, but how far would the amphidromes move?
>
> Amphidromes (googles)?
>
> Quite possibly to wholly different locations.
>
> One would need a good simulator to figure that out.
One obvious case is the direct effect of Coriolis force on
amphidromes.
Relevant to southern England - English Channel. The tidal range is
modest around Isle of Wight - though nonzero - because of near-
amphidrome. Whereas the French shore of English Channel, gulf of Saint-
Malo and Channel Islands have a huge tidal range.
It is the Coriolis force that causes the amphidrome to be near English
shore. The Irish sea likewise has amphidrome on the Irish shore, south
of Dublin, and a huge tidal range on the opposite shore, Wales and
Mersey.
Switching the direction of Coriolis force would tend to move the
amphidromes across English Channel and Irish Sea - generating high
tidal range on Channel shore of England where it was previously low
etc.
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