Jet stream

Definition

A jet stream is a fast-flowing air current found in the atmosphere, typically occurring at altitudes of about 10 kilometers (6 miles) and flowing from west to east. Jet streams play a crucial role in shaping weather patterns and influencing temperature distributions, as they help transport air masses and can affect the movement of cyclones and anticyclones.

5 Must Know Facts For Your Next Test

1. Jet streams can vary in strength and position, significantly impacting global weather patterns by steering weather systems across different regions.
2. There are typically two main jet streams in each hemisphere: the polar jet stream and the subtropical jet stream, each located at different latitudes.
3. The speed of jet streams can exceed 200 miles per hour, making them some of the fastest winds on Earth.
4. Changes in the position and intensity of jet streams are closely linked to seasonal shifts and can be influenced by climate change.
5. Jet streams can create areas of turbulence for aircraft, particularly when flying near their boundaries where the winds change direction rapidly.

Review Questions

• How do jet streams influence weather patterns and the movement of air masses?
  • Jet streams influence weather patterns by acting as a steering mechanism for air masses. When a jet stream is positioned over a region, it can guide the movement of warm or cold air masses into that area, leading to significant changes in weather conditions. For instance, when a polar jet stream dips southward, it can bring colder temperatures and storm systems to mid-latitude regions.
• Discuss the relationship between jet streams and cyclones or anticyclones, including their development and movement.
  • Jet streams are essential in the development and movement of cyclones and anticyclones. They create favorable conditions for cyclogenesis by providing upper-level divergence that allows surface low-pressure systems to deepen. The position and strength of the jet stream can also dictate how quickly these systems move across regions; a strong jet stream may lead to rapid cyclone movement, while a weak jet may result in slower progression.
• Evaluate the potential impacts of climate change on jet streams and associated weather patterns.
  • Climate change is likely to alter jet stream patterns by affecting their intensity, position, and variability. Research suggests that warming temperatures could weaken the polar jet stream, leading to more stagnant weather patterns that might result in prolonged periods of heat or cold in certain regions. This could disrupt normal seasonal weather cycles and increase the frequency of extreme weather events such as heatwaves, heavy rainfall, or droughts.

Related terms

Tropopause: The boundary between the troposphere and the stratosphere, where jet streams are commonly found and characterized by a transition from decreasing temperature to increasing temperature with altitude.

Air Mass: A large body of air that has uniform temperature and humidity characteristics, which can be modified by jet streams as they interact with different regions.

Cyclogenesis: The process by which a low-pressure system or cyclone develops, often influenced by the positioning and strength of jet streams in the atmosphere.