The Coriolis Effect In Brief
September 27, 2011 Leave a comment
Bad Astronomy has a great, short explanation of the Coriolis Effect (at least I assume it’s great; it now comprises 100% of what I know about the Coriolis Effect). You should click over and read it, but if you’re really too lazy then I’ll take the challenge of trying to make the explanation even shorter; be forewarned that it’ll be only slightly shorter but much less goodtastic.
The Earth rotates. Different parts of the Earth rotate at different speeds; the equator rotates the fastest, the poles don’t rotate at all (I hope that’s intuitive). Say there’s a weather system at the equator; it’s rotating eastwards at max speed (but it’s stationary relative to the also-rotating-eastwards equator). If it moves away from the equator (north or south), suddenly its speed is faster than the rotation of the earth at that latitude, so it’s going to be moving east.
If a weather system is near the poles it’ll be rotating very slowly; now if it moves towards the equator, it’ll be going slower than the rotation of the Earth at that latitude, so it’ll start traveling west.
So if air is rushing into an area north and south, it’s going to end up rotating. If it’s in the northern hemisphere, the northbound air will loop east, the southbound air will loop west, forming a counterclockwise rotation, and the opposite in the southern hemisphere.
And that is why hurricanes rotate in those directions. Makes almost too much sense…