What phenomenon is primarily responsible for keeping atmospheric conditions stable over Antarctica?

The phenomenon primarily responsible for keeping atmospheric conditions stable over Antarctica is the polar vortex. The polar vortex is a large-scale circulation pattern in the stratosphere that influences weather conditions in polar regions. It is characterized by a powerful, counterclockwise flow of air that locks cold air over the polar areas, thus maintaining stable, frigid temperatures. During the winter months, the polar vortex strengthens, further isolating Antarctica from warmer air masses found at lower latitudes.

This is significant as it helps to create and maintain the extreme cold and stable atmospheric conditions typical of the Antarctic region. The stability contributed by the polar vortex is essential for the preservation of the Antarctic ice sheets and the cold desert conditions prevalent in the area.

In contrast, El Niño primarily affects tropical and subtropical climates, influencing weather patterns globally but not specifically maintaining stability over Antarctica. Jet streams are also important for weather patterns, but they can lead to more variability and movement of air masses rather than the stability provided by the polar vortex. Trade winds are important in equatorial regions for ocean currents and weather but do not play a major role in the atmospheric conditions of Antarctica.