What happens in a global convection cell

The wind pattern that occurs in the atmosphere of the earth over a large scale refers to the convection cells. The water in the equatorial region receives a maximum amount of sunlight, as a result of which it becomes warm and less dense. This lighter is then rises up forming a low-pressure one and starts moving towards the poles in both the hemispheres. These lighter air mass then cools down as it reaches the poles and eventually gets denser and sinks down. This dense cold water further flows back to the equator moving at the seafloor.

During its motion from the equator to the poles, the air gets deflected due to a force that generates because of the earth's rotation. This force is known as the Coriolis force. This causes the wind to flow in a clockwise manner in the northern hemisphere, and anticlockwise in the southern hemisphere.

Due to this motion of wind and the effect of Coriolis force, the low-pressure zones are formed at the equator and the Arctic and Antarctic circles, whereas the high-pressure zones are formed at the near-tropical region and the poles.