- #1
hagar
Gold Member
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How much affect does the rotation of the Earth (such as drag friction) have on the motion of the atmosphere (if any).
Respectfully,
Hagar
Respectfully,
Hagar
The rotation of the earth/atmosphere affects air flow due to the coriolis effect. The Earth and the atmosphere as a whole rotates together at the same rate. However, the sun causes convective flows within that rotating atmosphere and this causes moving air masses to rotate due to coriolis effects (eg. hurricanes).hagar said:How much affect does the rotation of the Earth (such as drag friction) have on the motion of the atmosphere (if any).
Respectfully,
Hagar
Tropical cyclones are called hurricanes, typhoons, or cyclones, based on where they occur. That's just a naming convention. They are all manifestations of the same phenomenon. To answer your question, tropical cyclones rotate rotate counter-clockwise (when viewed from above) in the northern hemisphere, clockwise in the southern hemisphere.hagar said:Thank you for the response .
Does the coriolis effect change direction of the hurricanes rotation depending on whither they are in the northern or southern hemisphere ?
That's a load of malarkey. If you take a trip to a place right on the equator, you will be able to find people who will show you (for a fee, of course) water draining from a pan in one direction north of the equator and in the opposite direction south of the equator. The people who show you this supposed effect are charlatans. They are using pans that are designed to drain in one direction.I have been told rotating water such as water going down a drain turns in a reverse direction if it is located in the opposite hemisphere and if this is true ...
The Earth rotates from west to east. The speed of the rotating air/earth varies with latitude. So as air moves away from the equator, it begins traveling to the east at a faster rate than the Earth below it so it appears to be pushed to the east. For air moving to the northern hemisphere this effect results in counter-clockwise rotation of air being drawn into a low pressure area (such as the eye of a forming hurricane). In the southern hemisphere the effect is clockwise.hagar said:Thank you for the response .
Does the coriolis effect change direction of the hurricanes rotation depending on whither they are in the northern or southern hemisphere ? I have been told rotating water such as water going down a drain turns in a reverse direction if it is located in the opposite hemisphere and if this is true I wonder if it would be the same with wind rotation.
That's not a good way to look at the coriolis effect. How do you explain the trade winds (which flow from east to west with respect to the rotating Earth) with that model?Andrew Mason said:The Earth rotates from west to east. The speed of the rotating air/earth varies with latitude. So as air moves away from the equator, it begins traveling to the east at a faster rate than the Earth below it so it appears to be pushed to the east.
I said much the same (I said it's a load of malarkey). That is indeed the case for a small pan.But the effect is not observable in drains.
The one video I saw of this being shown to a bunch of tourists, had a symmetrical bowl on a stand, with a drain in the centre, which drained to a bucket underneath. The bowl was then carried a few metres farther, 'over the equator', where it was refilled from the bucket and allowed to drain again. The direction of rotation was induced during the refill phase (which direction the bucket was emptied towards), leading to the residual rotation being amplified as the water drained.D H said:The effect won't be observed if the pan is asymmetric or if there is any residual rotation. The specially-prepared pans used by charlatans at the equator to demonstrate the coriolis effect are asymmetric. A rotation does result, but it's because of this asymmetry rather than the coriolis effect.
Water draining out of a bath tub most definitely does develop a nice swirl, but this is not due to the Coriolis effect. There are several things that work against seeing the Coriolis effect set up in a draining bath tub:hagar said:Thanks to all for your answers. They resolved my question completely. I had not thought about using a small pan but I was referring to a larger amount of water like a bath tub drain because of course I have seen that occur.
I wasn't attempting to explain trade winds. Air movement occurs due to convection currents created by the sun and the effects of heat absorbed by land masses and water and the movement of water in the ocean currents. The direction of those movements is very complicated and requires detailed study. I don't know if the coriolis effect has much to do with the direction of those winds.D H said:That's not a good way to look at the coriolis effect. How do you explain the trade winds (which flow from east to west with respect to the rotating Earth) with that model?
No! The direction in which water drains from a bathtub has **nothing** to do with which hemisphere the bathtub is in.hagar said:Very interesting. It would seem the draining water left to its own devices will always spin anticlockwise, at least for us.
Would you provide a scholarly or peer reviewed reference to substantiate this particular sentence, please?Andrew Mason said:The Earth and the atmosphere as a whole rotates together at the same rate.
D H said:No! The direction in which water drains from a bathtub has **nothing** to do with which hemisphere the bathtub is in.
The first thing to note is that is not a bathtub. It is a specially designed circular tank with a drain at dead center. The second thing to note is that Tumlirz didn't wait long enough. Various people tried to recreate his experiment and the results were inconclusive. They were conclusive with an even longer wait time than the mere 24 hours that Tumlirz used.Dotini said:With respect to this question, I ran across this: ...
rootone said:...overall the Earth is a single body and the atmosphere is just it's outermost region.
This is the coriolis effect.Dotini said:Now a new answer is introduced with inertia and conservation of momentum as noted in post #18 above. ...
"The momentum the air has as it travels around the Earth is conserved, which means as the air that's over the equator starts moving toward one of the poles, it keeps its eastward motion constant." http://www.srh.noaa.gov/jetstream/global/jet.htm
The rotating reference frame is the rotating earth. The apparent "deflection" of moving air moving over the Earth surface is due to inertia of the air: the air tending to maintain its west-east velocity as it moves across the Earth surface.Dotini said:The Coriolis effect is a deflection of moving objects when the motion is described relative to a rotating reference frame.
Andrew Mason said:I wasn't attempting to explain trade winds. Air movement occurs due to convection currents created by the sun and the effects of heat absorbed by land masses and water and the movement of water in the ocean currents. The direction of those movements is very complicated and requires detailed study. I don't know if the coriolis effect has much to do with the direction of those winds.
I was just saying that if air is drawn for whatever reason from the equator northward, it will tend to curl east and if it is drawn from the north toward the equator it will tend to curl west. This results in counterclockwise rotation of air drawn to a low pressure area situated north of the equator and a clockwise rotation of air drawn into a low pressure area south of the equator.
AM
Earth's rotation is caused by the planet's initial spin when it was formed, as well as the gravitational pull of the moon and other celestial bodies.
Earth's rotation creates the Coriolis effect, which causes the paths of moving objects in the atmosphere (such as winds and storms) to curve.
The rotation of the Earth causes winds to move in a curved path, which can lead to the formation of high and low pressure systems, as well as the direction of storms and hurricanes.
The faster the Earth rotates, the stronger the Coriolis effect becomes, leading to more significant curved paths of atmospheric motion. This can impact the strength and direction of winds and storms.
Yes, factors such as the tilt of Earth's axis, changes in the Earth's crust, and variations in the Earth's orbit around the sun can also impact the rotation and atmospheric motion on our planet.