Upper Winds & Jet Streams. Upper air circulation & winds. Friction is said to be insignificant in the upper air circulation. Why? How does it affect the upper wind air circulation?. Upper wind circulation. Winds at the top of the troposphere are generally poleward and westerly in direction.
Simplified global three-cell upper air circulation patterns.
Satellite view of the atmospheric circulation at the South Pole. (Source: NASA).
Jet streams – the narrow bands of extremely fast-
moving air within Rossby waves (>230 km/hr)
- winter vs summer
2. Different jet streams
- significant vs seasonal
a. Polar front jet stream PFJS
b. Subtropical jet stream STJS
c. Easterly equatorial jet stream
(~summer monsoon system)