CHARLOTTE, NC (WBTV) - Have you ever wondered why we have weather? It isn't just so that we can have rain for the crops and wind to distribute seeds. We NEED weather so that the earth doesn't overheat.
Here's how it works. The earth is round and not flat. (Hopefully we all know that.) What you may not realize is that because it isn't flat, the sun's rays don't fall evenly across the earth's surface. The equator gets more direct sun than the poles. That means the equator heats up more than the poles. That makes for one out of balance planet! In order for the earth not to overheat, the warm air needs to be redistributed. "Weather" is how that happens.
The atmosphere is all about balance. It wants to get the extra warm air to where it's cooler. There are two main ways the air can move – vertically and horizontally.
An example of heat being transported vertically is when you have convection – which is basically rising air. On a hot day, warm air rises. As it does, it cools and condenses. By this process, heat is liberated. The heat is moved from the earth's surface and set free higher up in the atmosphere, where it's cooler.
Heat is transported horizontally by wind. Remember the wind belts you learned about in high school? Their purpose is to get extra heat from the equator to the poles. Have you noticed that our weather in the US typically goes from west to east? That's because we live in the wind belt called the "westerlies". That's part of the bigger system of winds belts, sending the extra heat toward the north pole. Also, the purpose of our high and low pressure systems is to send warm air toward the north and cooler air toward the south.
Clouds, wind and precipitation are all products of the uneven heating of the earth's surface. Isn't it cool how these things work?