WIND Flashcards
What is wind?
The movement of air in the atmosphere horizontally, (the most common). Caused by horizontal pressure differences.
Closely spaced isobars mean
Steep pressure gradient and strong wind
Widely spaced isobars mean
Shallow pressure gradient, and relatively light wind
Pressure gradient
This is the rate of change of pressure over a distance indicated by the actual spacing of the isobars
Advection =
Horizontal movement of air
Convection
Rising heated air
Illustrate the Coriolis force
Two Kids on a merry-go-round. Kid, A standing in the middle of the roundabout, throwing a ball to person B who is standing at the edge of the roundabout, if A throws the ball, straight at B by the time the ball has reached the edge of the roundabout be has gone further around and will not be able to receive the ball.
Isobars
These are imaginary lines which join points of equal MSL pressure
Standard ISA, sea level pressure is what in hecto pascals
1013 hPa
Pressure gradient
This is the rate of change of pressure over a distance indicated by spacing of isobars
If the isobars are close together, what is the result?
MUST KNOW
The pressure gradient is steep, producing strong winds
Subsidence
The downward movement of air
Cold air sinking
Resultant wind
Geostrophic wind is the resultant wind at Heights approximately 2000 and 3000 feet above the ground
Buys ballot
His law states that if you stand with your back to the wind in the northern hemisphere, the low pressure is always on the left, and the high pressure is always on the right.
What direction is the Coriolis force?
The opposite direction to the pressure gradient force