Question

What causes the seasonal shifting of pressure belts?

Answer 1

The seasonal shifting of pressure belts is caused primarily by the tilt of the Earth’s axis (approximately 23½°) and its revolution around the Sun. Because of this tilt, the Sun's vertical rays fall on different latitudes at different times of the year, causing the heating and, consequently, the positions of the pressure belts to shift northwards by about 5° in summer and southwards by about 5° in winter.

• At the Summer Solstice (around June 21), the Sun is directly overhead at the Tropic of Cancer `(23 1/2°N)`, causing most pressure belts to shift northward.
• At the Winter Solstice (around December 22), the Sun is overhead at the Tropic of Capricorn `(23 1/2°S)`, causing the pressure belts to shift southward.
• During the Equinoxes (around March 22 and September 23), the Sun is overhead at the Equator, and the pressure belts return to their original positions.

This seasonal movement of pressure belts influences wind patterns, rainfall distribution, and climate, such as causing the monsoons with wind direction reversals and shifting rain zones. It also affects wind belts like the Westerlies and Trade Winds, which move accordingly with the pressure belts.