Polar jet stream

Definition

The polar jet stream is a fast-flowing, narrow air current found high in the atmosphere, typically located between 30° and 60° latitude in both hemispheres. It plays a crucial role in influencing weather patterns by separating cold polar air from warmer air to the south, thereby affecting storm tracks and temperature distribution across regions.

5 Must Know Facts For Your Next Test

1. The polar jet stream can reach speeds of over 200 miles per hour, especially during winter months when temperature contrasts are greatest.
2. It typically follows a wavy pattern, which can lead to significant variations in weather, including prolonged cold spells or heat waves in certain areas.
3. Changes in the polar jet stream can influence the occurrence and intensity of storms, such as mid-latitude cyclones, impacting precipitation patterns.
4. The position of the polar jet stream can shift due to factors like sea surface temperatures and Arctic warming, which may alter typical weather patterns.
5. Meteorologists monitor the polar jet stream closely as its behavior is key to predicting short-term weather changes and long-term climate trends.

Review Questions

• How does the polar jet stream influence regional weather patterns?
  • The polar jet stream acts as a boundary between cold polar air and warmer southern air, playing a vital role in shaping regional weather. Its position determines where storms develop and track, affecting temperature and precipitation patterns. For example, when the jet stream dips southward, it can bring colder air and increased storm activity to lower latitudes.
• Discuss the relationship between the polar jet stream and Rossby waves. How do they interact to affect weather systems?
  • Rossby waves are large undulations in the jet stream that help to redistribute heat and influence weather systems across the globe. As these waves interact with the polar jet stream, they can amplify or weaken its flow, leading to changes in weather patterns. For instance, when Rossby waves are more pronounced, they can cause extended periods of unusual weather by trapping air masses in certain regions.
• Evaluate how climate change might impact the behavior of the polar jet stream and what implications this could have for global weather patterns.
  • Climate change is expected to alter the behavior of the polar jet stream by affecting its strength and position. As Arctic temperatures rise faster than those in lower latitudes, this temperature contrast diminishes, potentially leading to a weaker jet stream. A weaker or more erratic polar jet could result in more extreme weather events, such as prolonged heatwaves or cold spells, altering rainfall patterns globally and posing challenges for agriculture and water resources.

Related terms

Jet Stream: A narrow band of strong winds in the upper levels of the atmosphere that influences weather patterns and can be found at various latitudes.

Rossby Waves: Large-scale meanders in high-altitude winds that affect the movement of air masses and are closely associated with the polar jet stream.

Thermal Wind: The difference in wind speed and direction with altitude that arises due to temperature gradients, which is essential for understanding jet streams.