“1) Relative to the inertial frame, the earth is observed
to spin.
2) Due to friction, we are not surprised to find that
on average, the atmosphere spins along with the solid
earth. We take this as a zeroth-order approximation
to the actual behavior.
3) There are various local effects such as uneven solar
heating, orography, precipitation (which liberates a
lot of latent heat), et cetera. Sometimes these result
in a local updraft. This leaves us with a local low
pressure area.
4) As the rotating air mass falls into the low pressure
area, the rate of spin increases. This can be explained
in terms of conservation of angular momentum. It can
equally well be explained in terms of conservation of
linear momentum, in accordance with Newton's third law,
if you want to do things the hard way.”
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There seems to be a lacuna in this chain of reasoning:
How does spin of an air mass about the earth’s axis, stated in (2), become
spin about a low pressure center, presumed in (4) ?
There is lacking a mechanism for STARTING THE SPIN ABOUT THE LOW PRESSURE
CENTER. In the rotating frame this is provided by the Coriolis effect.
What is the dynamical mechanism as viewed from an inertial frame?