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Angular speed of the Earth's atmosphere

  1. Jun 16, 2010 #1
    Does the Earth's atmosphere match the angular speed of the Earth (i.e. is it stationary with respect to the Earth's surface, or is it "sliding" over the Earth's surface)? I'm trying to understand if the Coriolis effect that is creating the spiral pattern present in hurricane would be the same pattern if the hurricane was somehow "fixed" to the Earth's surface (if perhaps the water droplets could be represented by bowling balls rolling on the ground in the pattern of a low pressure system).

    Is the Corliolis effect stronger for planets with greater angular speed?
  2. jcsd
  3. Jun 16, 2010 #2
    CE apparently works for stationary polar ice caps. Replace your bowling balls with dust and ices.


    Great Red Spot, Batman
  4. Jun 18, 2010 #3
    Thank you for guiding me to that article. The wind at the martian ice cap is being steered/twisted by the CE as it collects and subsequently deposits ice crystals into the spiral pattern.

    I was also wondering if the Earth's atmosphere matches the angular speed of the Earth? Or does the Earth "slide" underneath the atmosphere, the movement of which is driven primarily by temperature and pressure gradients and independent of interaction with Earth's surface?
  5. Jun 20, 2010 #4
    How could you even imagine that the atmoshere is spinning 'round as though attached to the surface?? Influenced, yes .. by gravity and friction and certainly other forces (solar convection, etc) .. Were it 'attached' there's be no winds!
  6. Jun 20, 2010 #5


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    Were the atmosphere not spinning with the earth we would experiance (at the equator) winds on the order of 1000mph. So while the atmosphere may not be attached, it does spin with the same angual velocity as the earth.
  7. Jun 21, 2010 #6


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    I would have guessed the angular velocity of the atmosphere was a function of the distance from the surface with distortions around mountains.
  8. Jun 30, 2010 #7
    From what I understand, the atmospheric circulation is caused by differential heating of the Earth's surface, which subsequently causes a pressure gradient in the atmosphere, and the Coriolis effect, which acts to deflect air currents moving through the pressure gradient. I don't understand why convection currents couldn't occur and drive weather patterns while the atmosphere as a whole is stationary wrt the Earth's surface?

    From http://en.wikipedia.org/wiki/Wind#Cause": "Wind is caused by differences in pressure. When a difference in pressure exists, the air is accelerated from higher to lower pressure. On a rotating planet the air will be deflected by the Coriolis effect, except exactly on the equator. Globally, the two major driving factors of large scale winds (the atmospheric circulation) are the differential heating between the equator and the poles (difference in absorption of solar energy leading to buoyancy forces) and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, the large-scale winds tend to approach geostrophic balance. Near the Earth's surface, friction causes the wind to be slower than it would be otherwise. Surface friction also causes winds to blow more inward into low pressure areas."

    Why does the Earth's atmosphere spin with the same angular speed as its surface? Purely a transference of friction from its surface?
    Last edited by a moderator: Apr 25, 2017
  9. Jun 30, 2010 #8


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    Within naive models, the entire atmosphere has the same rotational velocity - there is no drag at the top of the atmosphere and the whole block of air behaves somewhat like a rigid body attached to the earth. The question of how true this is was important back as early as the 1960s, when satellites were starting to go up, and it was important to correct for drag at the upper atmosphere. Measurements from a number of these early satellites showed that the upper atmosphere was, in fact, rotating faster than the Earth!

    See, for instance, D. G. King-Hele, Planetary and Space Science, Volume 12, Issue 9, September 1964, Pages 835-853

    Last edited by a moderator: Apr 25, 2017
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