NationStates Jolt Archive

Does a planet's rotational speed affect the Coriolis in any way?

Of course it does. The Coriolis force is completely relient on the planet's rotation; without it, the effect wouldn't exist.

Okay...

Take this good old fashioned hurricane.

http://www.weatherworks.com/satellite/hurricanes_folder/hurricane2.jpg

Now, imagine a very slow spinning planet, with a day of, say, 622.9 hours. What would the above hurricane look like on that planet?

Like one of those miniature dust tornadoes you get sometimes with leaves in parking lots. Basically nonexistent.

What about gravity? How does that affect coriolis?

It doesn't. The effect is generated by the Earth's rotation; slow it down or speed it up, and you will similarly slow down or speed up the effect. It's the only thing that generates the effect; nothing else will affect it.

What about airflow between low and high pressure systems? In a slow spinning planet, would the airflow pretty much go straight from high pressure systems to low pressure systems, since the coriolis is too weak to bend the flow?

EDIT: I'm refering to storm systems.

That's where I'm not too sure...but I believe that it's safe to say that the coriolos is what causes wind patterns and the like to begin with, so the weaker it is, the weaker the storm systems and pressures will be. Thus, I think you'd actually have the same effect you do with our own weather system, only on a smaller scale due to the weaker effect.

So basically, the chance of seeing a tornado on a slow-spinning planet is about the same as winning the powerball?

Pretty much. Especially if it has a thin atmosphere.

What about a thicker atmosphere? (NOT venuslike-thick).

Even so, without the rotational speed, the effect will be minimal at best.

Thanks for your help, PIcaRDMPCia. ;)

Others, feel free to pitch in. :)

pretty much it, similar thing is seen in any rotating system, momentum and curved surfaces.

I think that a change in gravity would alter the coriolis effect, simply by increasing the atmospheric pressure, thus causing the effected air molecules to be pushed into the ground. The coriolis force would be the same, but it seems to me that the resulting spiral would be widened.

The Coriolis force on any object in a rotating reference frame is given by:

F(coriolis) = -2m(w x v)

Where:
m = mass of the object
w = angular velocity of the rotating reference frame (ie, Earth) (also, the 'w' is supposed to be 'omega', but I can't input that here, and they look similar)
v = velocity of the object in the rotating reference frame

That 'x' indicates a cross-product of vectors. If you don't know what that means, I don't have time to explain it to you.

The Coriolis force is an imaginary force, much like the centrifugal force. It only applies with regards to a rotating reference frame, from the perspective of something within the rotating reference frame. It only appears that there is a force, but in reality it's just an artifact of inertia.

Gravity has nothing to do with it, since motion tangential to the gravitational force is not affected by gravity.

Furthermore, in determining the deflection of an object as caused by the Coriolis force, the mass of the object will cancel out of the equation. All objects of any mass will deflect equally under otherwise identical circumstances.

The Coriolis force on any object in a rotating reference frame is given by:

F(coriolis) = -2m(w x v)

Where:
m = mass of the object
w = angular velocity of the rotating reference frame (ie, Earth) (also, the 'w' is supposed to be 'omega', but I can't input that here, and they look similar)
v = velocity of the object in the rotating reference frame

That 'x' indicates a cross-product of vectors. If you don't know what that means, I don't have time to explain it to you.

The Coriolis force is an imaginary force, much like the centrifugal force. It only applies with regards to a rotating reference frame, from the perspective of something within the rotating reference frame. It only appears that there is a force, but in reality it's just an artifact of inertia.

Gravity has nothing to do with it, since motion tangential to the gravitational force is not affected by gravity.

Furthermore, in determining the deflection of an object as caused by the Coriolis force, the mass of the object will cancel out of the equation. All objects of any mass will deflect equally under otherwise identical circumstances.

Yes that is the coreolis force. The coreolis effect however is the spiral nature of storm systems and toilet bowl flushing water. Since a change in gravity would produce a change in atmospheric pressure, why would it not cause a change in the coreolis effect, namely, increase or decrease in the radius of the spirals?

It doesn't. The effect is generated by the Earth's rotation; slow it down or speed it up, and you will similarly slow down or speed up the effect. It's the only thing that generates the effect; nothing else will affect it.
It does. You need gravity to keep an atmosphere. Or liquid water for that matter. I guess you could see the coreolis effect in molten rock on a small, hot planet with not atmosphere, nevermind.

Yes that is the coreolis force. The coreolis effect however is the spiral nature of storm systems and toilet bowl flushing water. Since a change in gravity would produce a change in atmospheric pressure, why would it not cause a change in the coreolis effect, namely, increase or decrease in the radius of the spirals?
So basically, a planet twice the size of earth could have superstorms as depicted below?

http://img160.exs.cx/img160/1909/bellehadesmegastorm3se.png

(Yes, this planet is the same one from my Deneb region. :D)

Yes that is the coreolis force. The coreolis effect however is the spiral nature of storm systems and toilet bowl flushing water. Since a change in gravity would produce a change in atmospheric pressure, why would it not cause a change in the coreolis effect, namely, increase or decrease in the radius of the spirals?

The Coriolis force of Earth spinning is not strong enough to affect the toilet bowl. Read the text about this "Bad Coriolis" myth: http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html

But the strength of the Coriolis effect is the function of the Coriolis force. Neptune is a big planet, and so there are storms with windspeeds of 2000 km/h in Neptune.

www.badastronomy.com also has a very nice explanation of the toilet-bowl myth, as well as a lot of other astronomical misconceptions. Very excellent website.

And the coup de grace for the toilet-bowl misconception: the water in a toilet-bowl is nozzled. It would spin in the same direction even if you ripped it out of your wall, flew to Australia, and hijacked Steve Irwin's water main to flush it, because there are holes in the toilet rim that direct the water.

Just one additional point here ... don't forget the impact of the temperature differential between night and day, arctic and temperate regions, etc. In a slow-rotating planet, the night/day temp differential would be higher, so the prevailing winds would most likely be faster. Yes??