Wind speed and direction
The wind is a movement of air that occurs parallel to the earth’s surface and is horizontal. The main property of such a flow is considered to be its velocity vector. In practice, this value represents a numeric value. Additional features are wind direction and strength. According to these criteria, there are several classifications at once.
The wind on planet Earth is a stream of air, mostly moving horizontally. A similar phenomenon is observed on other space bodies. However, in this case we are already talking about the flow of atmospheric gases. So distinguish solar and planetary winds.
Air flows on Earth are classified by speed, scale, strength, impact on objects and areas of distribution. However, the main characteristic is still the direction of the wind. Also, do not forget about its duration. It is by these criteria that winds are classified first. For example, short-term and long-lasting, strong and weak, etc.Powerful short streams are called squalls. Their duration rarely exceeds 1 minute. The longest can be identified breeze, storm, storm, typhoon and hurricane. All of them are additionally characterized by the forces of appearance and impact. In turn, the duration of the wind can be from a couple of seconds to several months. This phenomenon depends on the difference in the heating of air particles, relief features, and atmospheric circulation.
In rare cases, vertical winds occur. Their movement is directed upwards or vice versa. Such flows are called descending or ascending.
Methods for measuring performance
To find out which wind direction, you need to use one of the special devices. Each of these instruments shows the azimuth of the flow point. Totals will be in the range of 180 degrees.
Wind speed and direction can be measured with an anemometer. This device has found application in the energy industry. The flow hits a special membrane. The push is fixed by the sensor, the data is processed and displayed on the screen.
To measure the direction of the wind alone, you can use a conventional vane.This tool works even with the slightest whiff. As a result, the arrow will indicate the direction of the wind. The error depends on the quality of the weather vane. On average, it varies between 2-3%.If you do not have the necessary tools at hand, you can use your index finger. Just moisten it and set it up. Finger quickly feel the coolness. Thus, it is possible to determine from which side the flow is moving. On the other hand, this technology does not work in hot humid climatic conditions.
Direction of the wind
The movement of air flow is determined horizontally on the side from which it proceeds. If it blows to the north, then the wind direction is south. Such a movement is directly dependent on the force of rotation of the planet and the distribution of atmospheric pressure. The closer the flows to the surface of the Earth, the more variable they are.
As you know, water and land are heated at different speeds. In summer, the temperature of the earth's surface rises rapidly. Because of this phenomenon, the air heats up, expands and becomes much easier. In turn, above the surface of the water is always colder. Consequently, the air flow becomes heavier and more concise.Therefore, it is from the water side that the cool wind always blows. At night, streams often emanate from the shore.Another place of occurrence of winds can be mountainous terrain. In this case, the dry and warm stream is called "fen", and the strong and cold stream is called "boron".
Wind speed classification
This characteristic is measured in points or meters per second. Depends on the so-called baric gradient. The smaller its value, the lower the flow rate. Reference: 1 point is approximately equal to 2 m / s.
It is true that wind strength directly depends on its speed. In addition, the greater the pressure difference between the involved parts of the surface, the more powerful the flow will be. To date, there is a Beaufort scale, which is determined by the strength of the wind:
0 points. Category: calm. The determining flow rate is up to 0.2 m / s.
1 point Category: quiet. Speed - up to 1.5 m / s.
2 points. Category: easy. Its speed is up to 3.3 m / s.
3 points. Wind category: weak. The speed ranges from 3.4 to 5.4 m / s.
4 points. Category: moderate. Its speed performance is up to 7.9 m / s.
5 points. Category: fresh. The speed is from 8 to 10.7 m / s.
6 points. Wind category: strong.Its speed is up to 13.8 m / s.7 points. Category: strong. The speed varies from 13.9 to 17.1 m / s.
8 points. Category: very strong. Its speed is up to 20.7 m / s.
9 points. Category: storm. The flow velocity is up to 24.4 m / s.
10 points. Category: strong storm. Speed indicators - up to 28.4 m / s.
11 points. Category: hard storm. Its speed is from 28.5 to 32.6 m / s.
12 points. Stream category: hurricane. The speed ranges from 32.7 m / s and more.
The most powerful winds
A few years ago, the Beaufort scale was expanded by the US National Meteorological Service. Additions belong only to the category "hurricane":
- 12.1 points - strong windfall. Its speed ranges from 35 to 42 m / s. At the same time the wind changes direction constantly. The destructive impact extends to telegraph poles and wooden buildings.- 12.2 points. Such a hurricane has a speed of up to 49 m / s. Damage to roofs, doors and windows of stone buildings.
- 12.3 points. Wind with a speed of up to 58 m / s destroys the lungs of the house, catches up the waves with a height of up to 3.5 m. Flooding is possible.
- 12.4 points. Such a windfall is characterized by a speed of 59–70 m / s. The stream rips out the middle trees with roots, causing heavy damage to solid structures.
- 12.5 points.Wind with a speed of over 71 m / s destroys powerful buildings, including stone. Deep funnels remain in the ground. Heavy objects rise into the sky. Flooding is inevitable.
Most often, such flows are formed on the plains of the continent or above the sea. One of the most common species is breeze. In this case, the prevailing wind direction is characterized by the local circulation of warm air. It is formed due to the low pressure drop at a positive temperature.The speed of local winds rarely exceeds 4 m / s. More intense streams emanate from the mountain ranges. Formation occurs at heights, and a whiff - mainly in the valleys.
We are talking about monsoons and trade winds. The first kind of global winds is seasonal. He changes his direction only 2 times a year. Tropical monsoons move from mid-latitudes. They are mostly warm. Extra-tropical blows from polar and temperate latitudes, significantly reducing air temperature.
Trade winds depend on atmospheric pressure. More often blow from the west. In rare cases, you can observe the eastern and southern trade winds.The main distribution location is the equatorial zone.