Subtropical highs

Definition

Subtropical highs are large, semi-permanent high-pressure systems that typically form around 30 degrees latitude in both hemispheres. These high-pressure areas result from the sinking motion of air in the Hadley cell circulation, leading to dry and stable conditions that influence weather patterns and climate in surrounding regions.

5 Must Know Facts For Your Next Test

1. Subtropical highs are often associated with deserts because their sinking air inhibits cloud formation and precipitation.
2. These high-pressure systems can affect ocean currents, contributing to phenomena like the North Atlantic Gyre and affecting marine weather.
3. Seasonal variations can cause changes in the strength and location of subtropical highs, which can impact monsoon systems in adjacent regions.
4. Subtropical highs are a key component of Earth's general circulation and play a vital role in understanding global climate patterns.
5. They influence jet streams, which can lead to significant weather events like droughts or heavy rainfall when displaced.

Review Questions

• How do subtropical highs influence local climates and ecosystems?
  • Subtropical highs influence local climates by creating dry and stable conditions due to their associated sinking air. This leads to reduced precipitation, which is why many desert regions, such as the Sahara and the Atacama, are found beneath these high-pressure systems. The lack of moisture affects ecosystems, often leading to specialized flora and fauna adapted to arid environments.
• Discuss the relationship between subtropical highs and trade winds in terms of atmospheric circulation.
  • Subtropical highs play a crucial role in shaping trade winds, which are the prevailing easterly winds found between 30 degrees latitude and the equator. The sinking air associated with these high-pressure systems creates a pressure gradient that drives the trade winds toward the equator. This movement is essential for maintaining the overall circulation pattern of the atmosphere, contributing to weather phenomena and ocean currents in tropical regions.
• Evaluate how changes in subtropical highs can impact global weather patterns and climate variability.
  • Changes in subtropical highs can have significant repercussions on global weather patterns and climate variability. For instance, if these high-pressure systems strengthen or shift position due to climate change, it could lead to alterations in rainfall distribution, affecting agricultural practices worldwide. Additionally, such shifts can impact ocean currents and exacerbate extreme weather events like hurricanes or prolonged droughts, highlighting the interconnectedness of atmospheric systems on a global scale.

Related terms

Hadley Cell:

A tropical atmospheric circulation system where warm air rises at the equator, moves poleward at high altitudes, and sinks in the subtropics, creating a loop.

Trade Winds: The prevailing easterly winds that blow from the subtropical highs toward the equator, significantly impacting weather patterns in tropical regions.

Doldrums: A region near the equator characterized by light winds and calm seas, situated between the trade wind belts of the northern and southern hemispheres.