Jet streams

Definition

Jet streams are fast-flowing, narrow air currents found in the atmosphere, typically located at altitudes of 6 to 12 kilometers (20,000 to 40,000 feet) above the Earth's surface. They play a crucial role in shaping weather patterns and influencing climate by transporting heat and moisture across long distances. These high-altitude winds are generally found in the tropopause and can have significant effects on storm development, precipitation patterns, and temperature distribution around the globe.

5 Must Know Facts For Your Next Test

1. Jet streams are typically found in the upper levels of the atmosphere and are strongest during winter months when temperature contrasts between polar and tropical air masses are most pronounced.
2. There are two main types of jet streams: the polar jet stream, which forms at the boundary between polar air and mid-latitude air, and the subtropical jet stream, located closer to the tropics.
3. Jet streams can influence the path of storms and weather systems, often steering them from west to east across continents.
4. Changes in jet stream patterns can lead to unusual weather phenomena, such as prolonged droughts or extreme winter conditions in certain regions.
5. The strength and position of jet streams are affected by various factors including ocean temperatures, such as El Niño and La Niña events, which can have global climate impacts.

Review Questions

• How do jet streams affect weather patterns across different regions?
  • Jet streams have a significant impact on weather patterns by influencing the movement of air masses and storm systems. They act like highways for weather fronts, guiding them from west to east. When jet streams dip southward, they can bring cold Arctic air into warmer regions, leading to sudden drops in temperature or winter storms. Conversely, when they shift northward, warmer tropical air can move into cooler areas, causing unseasonably warm weather.
• Evaluate how changes in jet stream behavior might contribute to extreme weather events.
  • Changes in jet stream behavior can significantly alter regional climates and contribute to extreme weather events. For instance, a slower-moving or meandering jet stream can result in prolonged periods of extreme temperatures—either hot or cold—as weather systems become stationary. This can lead to extended droughts or persistent heavy rainfall in certain areas. Additionally, alterations in jet stream patterns can amplify storm systems, leading to more intense hurricanes or blizzards.
• Synthesize information about how climate change may be influencing jet streams and the implications for global weather systems.
  • Climate change is believed to be affecting jet streams by altering their speed and position due to changes in temperature gradients between the poles and the equator. As the Arctic warms faster than other regions, this could lead to weaker and more erratic jet streams. This synthesis of information suggests that if jet streams become less stable, it could result in more extreme weather patterns globally—longer droughts in some regions, increased flooding in others, and greater variability in seasonal weather could all stem from these changes.

Related terms

tropopause: The boundary between the troposphere and stratosphere where jet streams are often located, characterized by a temperature inversion.

trade winds: Persistent east-to-west winds that occur in the tropics, contributing to ocean currents and influencing weather systems.

cyclones: Large-scale air mass that rotates around a center of low atmospheric pressure, heavily influenced by the presence and behavior of jet streams.