What causes the wind current to …

Wind Currents Are Generated Due To Uneven Heating On The Earth:

Wind is the movement of air which depends on the difference in air pressure in the two regions. The greater the difference in air pressure the faster the air moves.

There are following situations:

1. Uneven heating between the equator and the poles: The regions close to the equator get the maximum heat from the Sun. The air in these regions gets heated and warm. The warm air rises in the equatorial regions of the earth creating an area of low air pressure and the cooler air from the regions in the 0–30 degrees latitude belt on either side of the equator moves in. This makes the wind to blow from the north and the south towards the equator. At the poles, the air is colder than that at latitudes about 60 degrees. The warm air at these latitudes rises up and the cold wind from the Polar Regions rushes in, to take its place. In this way, wind circulation is set up from the poles to the warmer altitudes. The winds would have flown in the north-south direction from north to south, or from south to north. A change in direction is however, caused by the rotation of the earth on its axis.
2. Uneven heating of land and water: The land near the equator of earth heats up faster than the water in oceans in summers. The air over the land gets heated and rises. This causes the winds to flow from the oceans towards the land. These are monsoon winds. The monsoon winds carry lot of water from the oceans and bring large amount of rains on land. The process in which the winds coming from the oceans carry a lot of water vapour and bring rains is a part of the water cycle in nature. The summer monsoon is very important to the farmers because most of the annual rainfall occurs at this time and helps in growing crops.