Characteristics, names, causes, effects of the wind
The wind is present everywhere on Earth, it is a powerful and complex force that manifests itself in different ways at different intensities. There is no place where it is not present, it is the breath of our Earth. In this article we aim to explore the wind, understanding its characteristics, the causes of its movement, the various types and the effects it has on the environment and on human beings.
What is the wind for?
The wind is a natural phenomenon, it is the movement of air volumes that originates from the different temperatures of the Earth, it is the continuous movement of air from one area of depression to another. It has multiple uses for the ecosystem and for humans: for example, it is responsible for spreading seeds and spores, thus allowing vegetation to expand and move into new areas. The wind contributes to the formation of clouds and their “transportation” in the sky, becoming the absolute protagonist of the essential water cycle, the basis of life on our planet.
Furthermore, the wind is a real instrument of civilisation for human beings, because it has always been used for millennia as energy to navigate and thus discover new lands or increase traffic and communication between different civilisations and to exploit it as a primary source for work from the first mills to the dawn of the industrial revolution.
Windmills were invented in the Mesopotamian area (now Iraq) and were initially used to grind wheat and other cereals. Over time they have also been used for other activities, such as pumps to draw water up to the production of electricity in the modern age. Traditional windmills consisted of a wooden or stone structure with wooden or metal blades that were rotated by the wind and most mills were in the shape of a cylinder with a single sail (some even had multiple blades).
Today, wind turbines use wind energy to produce electricity, contributing to the transition to renewable energy sources. Additionally, the wind is used in many sports and leisure activities. In short, the wind is a natural phenomenon that is the protagonist for life on Earth.
Why does the wind blow: the causes
The wind is caused by pressure differences between different areas of the Earth. The atmospheric pressure is the force exerted by the air on the Earth’s surface and it varies according to place and time: when there are pressure differences between two areas, the air tends to move from the high pressure area to the low pressure area, thus creating the wind. The main cause of pressure differences is the temperature difference between areas.
Warm air, being less dense than cold air, tends to move upwards, creating an area of low pressure. Conversely, cold air, being denser, tends to move downwards, creating an area of high pressure. This process, known as convection, is the basis of surface-level winds.
The cyclonic wind, on the other hand, is caused by a lower pressure at the center of a depression and a higher pressure at the periphery. In addition, ocean currents and atmospheric disturbances can affect pressure differences and cause high winds and storms. In general, wind is caused by interactions between the Earth and the atmosphere, and its intensity and direction are influenced by many factors, including temperature, pressure, rotation of the Earth and atmospheric perturbations.
The types of wind: names, characteristics, periodicity
The wind can be classified according to its origin and its intensity, let’s see some types of wind below.
Surface-level winds are those that occur a few meters from the earth’s surface and are caused by differences of pressure and temperature between areas. Among these, the most common winds are breeze winds, caused by the temperature differences between the earth and the air, and monsoon winds, periodic and repetitive in tropical and subtropical regions.
Among the most common winds, we also find the trade winds, which occur between 30 and 60 degrees latitude and are caused by the pressure differences between the hot and cold air in that area of the globe and the jet stream winds which occur at great altitudes and are caused by the rotation of the Earth and by pressure differences between latitudes.
Then there are the seasonal winds, such as the monsoon winds, and local winds, such as the breeze winds that we find along the coasts: each of these winds has specific characteristics, such as direction, speed, frequency and duration.
Regarding the classification based on intensity, we can use the Beaufort scale, where a light breeze corresponds to a value of 2, a moderate breeze is classified with a number between 6 and 7, while a strong wind is classified with a number between 8 and 10. Beyond the number 10 it is a storm or hurricane.
The monsoon winds are seasonal winds that blow from south to north in some tropical and subtropical regions, such as Australia and Central America, and have a duration of about three months. Monsoon winds bring rain and humidity to affected regions, but they can also cause flooding and damage to crops.
In general, periodic winds are an important phenomenon for meteorology and human activities, as they have implications for agriculture, navigation and others, therefore their understanding and prediction are crucial for risk management and for the sustainable development of the regions concerned.