Carl-Gustaf Rossby was a very smart man who knew a lot about how the air moves around the Earth. He found out that there are big rivers of air called jet streams that move really fast high up in the sky.
He also discovered that the Earth's rotation (like when a spinning top keeps spinning around) makes the jet streams bend and turn in a certain way. This is really important because it helps us predict things like the weather, and it explains why certain parts of the world are warmer or colder than others.
Overall, Carl-Gustaf Rossby was a very important person who helped us understand how the Earth's air moves and why it's so important!