What is the term for the area of low upper-level heights above the polar regions?

• A. Polar vortex
• B. Subtropical high
• C. Intertropical convergence zone
• D. Mid-latitude cyclone

Answer: (A)

The term for the area of low upper-level heights above the polar regions is "polar vortex." This phenomenon refers to a large area of low pressure and cold air surrounding the Earth's poles. The polar vortex develops in the upper atmosphere, particularly during the winter months, and can significantly influence weather patterns by affecting the movement of the polar jet stream. The weakened polar vortex can lead to abnormal cold temperatures and weather patterns in mid-latitude regions, as exchanges of polar air masses with subtropical regions can occur.

In contrast, subtropical highs are large areas of high pressure typically found around 30 degrees latitude, influencing global weather patterns but not specifically related to the polar regions. The intertropical convergence zone is a region near the equator where trade winds from both hemispheres meet, causing convergence and often leading to cloud formation and precipitation, which is distinctly different from the dynamics of the polar vortex. Mid-latitude cyclones are low-pressure systems that form in the mid-latitudes, resulting from the interaction of warm and cold air masses, but they are not specifically tied to the polar regions in the same way as the polar vortex.