We have always understood wind as the movement of air from one area to another, something we cannot see unless it carries sand or other materials. People's curiosity about wind stems from how something we cannot see can be measured.
How do they measure the wind and what types of wind are there? What do experts use to refer to moving air by different names?
Why does the wind form?
There are several ways wind can be produced. The most common is when there are two points in different areas where a difference in pressure or temperature exists between them. When there are two points where the pressure varies, air masses will tend to move from the area of ​​higher pressure to the area of ​​lower pressure. This is similar to how, when we squeeze a tube of toothpaste, we create a pressure difference. The toothpaste tends to move from the area of ​​higher pressure to the area of ​​lower pressure. Meteorologists call this pressure difference a gradient.
Because wind and pressure are closely related, isobar maps are created. These maps represent pressure differences, which in turn provide information about wind speed and direction. Isobars are lines of equal pressure . Therefore, a map where isobars are close together indicates stronger winds, because the pressure changes significantly over a small area. It's also interesting to note how winds behave in different regions.
Source: http://sarablogcen.blogspot.com.es/2012/11/mapa-de-isobaras.html
When wind forms due to temperature differences, something else happens. When an air mass becomes warmer than its surroundings, its volume increases, which decreases its density. Due to buoyancy, the warm air mass rises, and its place is taken by other air masses, whose movement creates wind . This movement of warm and cold air masses is the origin of many summer storms and, on a larger scale, of the prevailing winds in the tropics. We can also see how these changes influence natural phenomena, such as Storm Éowyn.
The effects of Storm Garoe are another example of how winds can affect the climate of certain areas.
How is the wind measured?
Wind can be measured in different ways and in different units. The most used are:
- Measurement of horizontal wind speed: the most used instrument is the anemometer of cups, in which the rotation of the same is proportional to the speed of the wind. The unit of measurement is km / h or m / s.
- Direction measurement: for this they are used the weather vanes, which indicate the geographical origin of the wind. We speak of north, northeast, southwest wind, etc. depending on where it comes from.
To better understand the relationship between wind and its speed, it is important to refer to the Beaufort scale , which classifies wind intensities.
Some special types of wind
Sea breezes
You've surely felt a pleasant sea breeze on a hot beach day as you approach the shore. This happens because: During the day, the land heats up faster than the sea surface, so the air from the land rises and is replaced by cooler air from the sea. At night, the land cools down faster than the water, so the air above the sea surface is warmer and tends to rise, creating a flow of wind from land to sea. In this regard, it's also useful to know the prevailing winds in the Mediterranean.
Mountain and valley breezes
You may have also felt the cool breeze that occurs in many valleys at night. In this case, the following happens: During the day, the air in the valley heats up quickly and tends to rise up the hillside. At night, the cooling air becomes denser and descends from the peaks into the valley. This phenomenon is related to another type of wind, such as the katabatic wind.
It is important to take into account the effects of winds that generate extreme phenomena.
Hurricanes
The devastating effects of hurricanes are well known, especially when they strike populated areas where houses and buildings are not designed to withstand the force of the wind. A hurricane is a violent weather phenomenon that originates over tropical oceans, usually at the end of summer or the beginning of autumn. It originates from a uniform mass of hot, moist air that rises rapidly. Air pressure is distributed symmetrically around the center of the system, and isobars are concentric circles very close to each other. In a hurricane, winds can reach speeds of up to 250 km/h, although more typical values ​​are around 119 km/h. For more information on hurricanes, see the article on Hurricane Kirk . At the center of the hurricane is the so-called "eye ," an area of ​​clear skies and light winds.
Tornadoes
A tornado is a whirlwind of intense winds associated with the formation of cumulonimbus storm clouds. Tornadoes can originate over land or at sea from a rapid updraft of very warm air. The spiraling movement of the air gives it the typical funnel or waterspout appearance. Its path over land can range from 1,5 km to 160 km in the case of an intense tornado. Those that form over the sea are called waterspouts. The winds generated are around 180 km/h, although tornadoes with speeds of up to 500 km/h have been recorded. For more details, you can check the information about tornadoes in Spain.
