What factors affect air movement?

When you inflate a balloon, you create an area of high pressure; however, as soon as the balloon punctures, the air quickly moves from inside the balloon to the outside, where the air pressure is lower. Air flows from areas of high pressure to areas of low pressure.

Since there is almost constant air movement of some kind, we know that this is not the case. If that were the only factor affecting air movement, equilibrium would soon be reached and there would be no more air movement.

The Coriolis effect is the deflection of moving air caused by the Earth's rotation. To illustrate how air moves without the Earth's rotation being taken into account, take a paper plate and a marker, write a big H in the middle and a L near the edge, and draw a line from one to the other. Next, write a L at the 12 o'clock position and draw the line again, rotating the plate while you draw the line from the center to the 12 o'clock position. This time, however, you will have a curved line that doesn't actually connect the H and the L.

In the Northern Hemisphere, if you face the wind with your back to it, low pressure is on your left side. Similarly, if the plate were a ball and you continued to draw lines from the H to the L while the ball kept rotating, you would eventually end up with lines that run parallel between the H and L.

In the atmosphere, this means that the air near the surface of the Earth does not move directly parallel between areas of high pressure and low pressure, but rather gets slightly deflected inward toward a low pressure or outward from a high pressure. This is why low pressures eventually fill and high pressures eventually subside. Friction is the last factor, and it only affects the air movement in contact with the Earth (known as the boundary layer).

Several factors affect air movement, including temperature differences, pressure gradients, the Coriolis effect, friction, and geographic features such as mountains and bodies of water.