Okay kiddo, let's talk about barotropic. Imagine you have a big bowl of soup. If you mix the soup around, does it look the same everywhere in the bowl, or are there parts that are different than others? Well, the Earth is kind of like a big bowl of soup. But instead of soup, we're talking about the air and water in the atmosphere.
Barotropic is a big word that means the air and water in the atmosphere are all mixed up and look the same everywhere you go. Just like how the soup in the bowl looks the same everywhere once you mix it all around. It's like a big, even layer of air and water that wraps around the Earth.
So, when we say the atmosphere is barotropic, it means there aren't any big differences in the temperature or pressure of the air and water. Everything is pretty much the same from top to bottom and from side to side. It's kind of like having a nice, even blanket covering the Earth.