Winds which **** from high pressure belts to the low pressure belts in the same direction through out the year are called planetary winds, permanent winds or prevailing winds. Characteristics: The chief characteristics of planetary winds:
- They are connected with the pressure belts. So they **** from the high pressure belt or area to the low pressure belt or area.
- They are regular through out the year.
- They deflect to their right in the northern hemisphere and to their left in the southern hemisphere.
- As a result of the shifting of the pressure belt northward in summer and southward in winter, the planetary winds also shift northwards in summer and southwards in winter. They are permanent and **** over vast areas of the globe. These winds include trade winds, westerlies and polar winds.
1. Trade winds: The winds that **** in the tropics form the subtropical high pressure belts towards the equatorial low pressure belt are called “Trade winds”. They found approximately between 8° and 30° latitudes on both sides blowing from the east. They are also known as “Tropical Easterlies”.
The trade winds due to the law of deflection from the northeast in the northern hemisphere and from south-east in the southern hemisphere. Trade winds from the cooler subtropical areas to the hotter area, hence they do not bring rain. However, when they **** over the open sea they gather moisture and bring heavy rainfall to the east coast of the continents.
2. Anti trade winds: The wind blowing from sub-tropical high pressure belts towards sub-polar low pressure belts are known as anti-trade winds. They are south-west to north east in the northern hemisphere and Nor west to south-east in the southern hemisphere.
Hence they are called ‘Westerlies”. They prevail largely between 40° and 650 north and south of the equator. They from the north-west in the southern hemisphere and south – west in the northern hemisphere. As they from hotter areas to colder areas they bring rain through the year.
3. Polar winds: Winds blowing from polar high pressure belts toward the sub-polar low pressure belts are known as polar winds. They from the north east in the northern hemisphere and south east in the southern hemisphere. As they form the snow cov4red areas they are very cold winds. They are constant in the southern hemisphere.
