Introductory Meteorology

Lesson 11. The Tropics: Patterns of Wind, Water, and Weather


beach scene
The tropics are known for their persistent weather patterns.

Ah... the tropics! The perfect vacation spot. Sun, sand, surf, and the ever changing weather. What, you say? The reason why the tropics are a great vacation spot is because of the seemingly endless days of sunny skies and balmy breezes? Well, that's partly true about the tropics. Certainly the weather in the tropics is not dictated by the same driving factors as in the mid-latitudes -- namely temperature gradients. There are no cold fronts, warm fronts, and mid-latitude cyclones to contend with. But don't be fooled into thinking that the tropics don't have their share of interesting weather.

Aside from the occasional tropical cyclone (covered in the next lesson), the tropics are a region of persistent patterns. But what causes these patterns to remain the same over long periods? Why does the wind only seem to blow from one direction in the tropics? This means that the general pressure pattern within the tropics doesn't change much over fairly long time scales. Why is that? How can one area of the tropics be known for its abundance of sunny days, while other locations are known for persistent rain (i.e., the rain forests that ring the equator)? What about seasonal variations in weather? What's meant by saying a location has a "wet season" and a "dry season"? Furthermore, did you know that the tropics have some of the tallest thunderstorms on the planet? However, the organization mechanism for these thunderstorms is far different that for storms over the mid-latitudes. All this and I haven't even mentioned the Indian Monsoon and El Nino -- two of the more famous weather patterns in the tropics.

Indeed, tropical cyclones aside, the tropics are full of "weather" that needs studying. So, pull up a beach chair and let's get started!