3 ms·

I suspect it's more to do with the fact that (as Retric alludes to) the atmosphere is not a monolayer.

byrneseyeview 17y ago
I'm having trouble visualizing how a weather system with multiple layers would allow some points to have a horizontal speed of zero without creating cyclones. Is the implication here that there could be some permanent vertical flow of air, iff the atmosphere is layered?
- RiderOfGiraffes 17y ago
  "Creating Cyclones" is a mis-leading phrase. Consider air flowing from North Pole to South Pole at the surface, rising from the South Pole to an upper layer, returning to the North Pole, descending, and repeating. There are no cyclones, the flow is constant, and there are places with zero horizontal velocity. In reality the Earth rotates and the Coriolis force would create cyclonic circulations, but that's another matter. Down that path lies chaos.
  - byrneseyeview 17y ago
    How do the particles of air immediately adjacent to the zero-horizontal particles move?
    - RiderOfGiraffes 17y ago
      Well, first problem is to define "immediately adjacent". In analysis, there is no point "next to" the point 0. I assume you mean a small neighborhood. There are several ways to define these things. For example, in a small neighborhood, the particles could move at a speed proportional (ish) to the distance from the point. When you take 3D into account, some move tangentially, some move radially (ish) and it can all be smoothed out. It's easiest to imagine the entirety, then try to extend the macro movement smoothly into the corners. By using tricks such as asymptotic slowing it can all be done. Are you having trouble visualising? Or are you worrying about the precise details. This is not a good medium for discussing either. A good text or tutorial on fluid mechanics will cover the various techniques for mapping an obvious flow into a less obvious flow.

I'm having trouble visualizing how a weather system with multiple layers would allow some points to have a horizontal speed of zero without creating cyclones. Is the implication here that there could be some permanent vertical flow of air, iff the atmosphere is layered?

RiderOfGiraffes 17y ago
"Creating Cyclones" is a mis-leading phrase. Consider air flowing from North Pole to South Pole at the surface, rising from the South Pole to an upper layer, returning to the North Pole, descending, and repeating. There are no cyclones, the flow is constant, and there are places with zero horizontal velocity. In reality the Earth rotates and the Coriolis force would create cyclonic circulations, but that's another matter. Down that path lies chaos.
- byrneseyeview 17y ago
  How do the particles of air immediately adjacent to the zero-horizontal particles move?
  - RiderOfGiraffes 17y ago
    Well, first problem is to define "immediately adjacent". In analysis, there is no point "next to" the point 0. I assume you mean a small neighborhood. There are several ways to define these things. For example, in a small neighborhood, the particles could move at a speed proportional (ish) to the distance from the point. When you take 3D into account, some move tangentially, some move radially (ish) and it can all be smoothed out. It's easiest to imagine the entirety, then try to extend the macro movement smoothly into the corners. By using tricks such as asymptotic slowing it can all be done. Are you having trouble visualising? Or are you worrying about the precise details. This is not a good medium for discussing either. A good text or tutorial on fluid mechanics will cover the various techniques for mapping an obvious flow into a less obvious flow.