Geography
Answer
The causes of shifting of pressure belts are inclination of Earth's axis and change in relative position of Earth with Sun -
- At the time of Summer solstice the Sun is vertical over the Tropic of Cancer and therefore, all the pressure belts except the northern polar high pressure belt shift northward.
- After Autumn Equinox, there is southward migration of the Sun which becomes vertically over the Tropic of Capricorn at the time of Winter Solstice and therefore the pressure belt shifts southward except in the southern polar high pressure belt.
- The Sun is overhead over the Equator at the time of Spring Equinox and Autumn Equinox and hence all the pressure belts occupy their normal positions.
The shifting of pressure belts has the following consequences:
- It influences the areas of Mediterranean climate and the position of Westerlies which move northward in the summer season (June) and southward in the winter (December) season.
- The summer and winter monsoons and the complete reversal of wind direction are also the results of shift of pressure belts.
- Both the trade and anti-trade winds are thus closely influenced by the shift of belts.