Task: Text Categorization
Input (English): This phenomenon causes the formation of yardang ridges. The foehn and Chinook types of it are observed on the downward slopes of mountains. Its speed can be measured by an anemometer (ANN-uh-MOM-ett-er), but is usually given by the Beaufort scale. One specific type of it is the jet stream. This phenomenon is often nonexistent in the doldrums. For 10 points, name this flow of gases that moves kites by producing gusts and breezes.
Output (English): Science