Weather is created due to the day by changes in the atmosphere, and the motion of the earth spin, drags the atmosphere around with it, with the overall result being a combination of global patterns of wind which follow a regular yearly cycle.
Wind is created by the action of the Sun, heating up different parts of the land and sea by varying amounts. For example, the sun is overhead in the tropics, therefore it has less atmosphere to pass through so the effects of heat are greater. Warm air rises and cooler air flows alongside, replacing the displaced air resulting in large scale air movement or wind as we know it.
In the days of the sailing ship, wind was especially important because it gave the vessels the power to carry cargoes around the world. These main winds, such as the South East and North east Trades, the Westerlies and the Easterlies, got their names from these ancient mariners who relied on their charts to chart their vessels and avoid the worst effects of the weather.
The rotation of the earth means that it is a spinning globe where at one point of the equator is traveling at 1100 km/hour, whilst a point at the poles is not affected by rotation. This results in what is known as Coriolis forces which act to cause an apparent deflection of a motion. This can be explained in terms of an imaginary force that can be translated into terms of gravitational pressures.
In the Northern Hemisphere, winds circle around low pressure zones counter clockwise and around high pressure zones clockwise. In the southern hemisphere the opposite applies with the winds flowing round clockwise around low pressure zones and anti clockwise around high pressure zones.
Winds flowing into a low pressure area can develop into what is known as the Bernoulli Effect. This is when winds reach a high enough speed and begin to rotate around a low pressure zone. As the speed increases the winds are pulled closer inwards, gathering outer forces and marshaling them into an organized and controlled spin. This is what causes types of storms such as hurricanes.
The circulation of the Earth’s atmosphere gives us a similar effect. Due to the effects of the Sun and the effect of varying degree of heat on certain areas such as the equator and the Poles, resulting in surface winds or air moving towards the equator at the surface and towards the Poles at altitude. “At mid-latitudes we can see that air moves towards the Poles via the surface and moves to the Equator at altitude”.
The effects of wind force and direction dictates to a great extent to the type of weather we are going to experience. Winds are governed by gravitational effects of the Earth and are pushed into motion by the the heating effects of the sun.
As we gather more scientific evidence from the use of satellite and radar systems, a much clearer picture is emerging as to how the motion of the Earth, the effects of the sun and the composition of our atmosphere combine together to create what we have come to understand about the varying weather systems experienced on Earth.
Meteorologists are improving their knowledge daily, keen on unraveling the deeper mysteries of the most powerful force on Earth.