Thread: Discussion THERMALS: what do you know?
View Single Post
Old Nov 10, 2012, 08:17 PM
Daemon is offline
Find More Posts by Daemon
Registered User
Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
30,728 Posts
Repeating myself from an earlier discussion on the effects of the Coriolis effect.

Coriolis force is simply the earth turning under your feet while
large moving masses tend to follow a straight path due to inertia. Problem
is, we're only talking a maximum of 4 tenths of one percent of 1 degree
(that's 0.004 degree) per second of rotation at the highest latitudes, and less as you
approach the equator. We're about in the middle. It acts upon moving air
masses the size of states or countries as they're pulled into a low pressure
area, encouraging enough bend in their paths (as viewed from the
earth's rotating frame of reference) to start slow rotation which is only
accelerated enough to observe by decreasing rotational inertia as the system
contracts. But at the scale of the masses of wind that we fly it
might as well be compared to the flapping of butterfly wings for all
the effect it has.

What makes thermals and dust devils start turning is local effects. Surface wind
combined with unequal heating, ridges, valleys, treelines.. etc..

Daemon is offline Find More Posts by Daemon
Reply With Quote