Jet streams are typically located near which atmospheric boundary?

• A. The surface
• B. The tropopause
• C. The stratopause
• D. The mesopause

Answer: (B)

Jet streams are fast, narrow bands of winds that form high in the atmosphere. They arise near the boundary between the troposphere and the stratosphere—the tropopause—where the temperature contrast between cold polar air and warm tropical air creates a strong horizontal pressure gradient. The thermal wind relationship shows wind speeds increase with height where this gradient is steep, producing the jet stream right at the top of the troposphere. The surface is too rough and friction slows flows, and the stratopause or mesopause lie in different atmospheric layers where such fast, organized jets don’t typically form.