Winds are fast streams of air moving horizontally. They can be light and barely noticeable, and can be strong and powerful so that they demolish everything in its path. What is the nature of the wind? What is this “wind rose”? Let's find out.
Wind - what is it?
Wind exists not only on Earth. In its broadest sense, winds are flows of particles. They are present in space and on other planets and consist of matter inherent in one or another celestial body.
For example, on Neptune it is represented by hydrogen, helium, methane, ammonia and hydrogen sulfide. And the solar wind is represented by radiation streams that are emitted into outer space.
On our planet, winds are streams of air that moves in a horizontal direction. They appear due to the uneven heating of the Earth's surface by the Sun. So, different pressures form in different corners of the planet. The air begins to tend from the area of high pressure to the area with lower, hence the wind.
Winds are distinguished by force and speed, scale, impact on nature. Some flows occur suddenly and do not last long. Others are natural and appear only in a specific region and in a specific period. The graph that shows the air flow regime in a particular area is a wind rose.
Global winds
Global or predominant air masses participate in the general circulation of the atmosphere. They blow, as a rule, in one direction and participate in the formation of the climate on Earth. These include trade winds, monsoons, western temperate zones and eastern winds of the polar regions.
The polar front and subtropical ridge are peculiar boundaries. Here the air masses move mainly vertically. In the subtropics, however, they change direction once every six months, coming either from the temperate zone or from the tropics.
Westerly winds blow within 35-65 latitudes. In the Northern Hemisphere they come from the southwest, in the Southern Hemisphere from the northwest. They are strong in winter and very weak in summer. These air currents influence the formation of powerful currents in the ocean, carrying the warm waters of the tropics to the poles.
Eastern polar winds are not as strong and regular as western ones. These are dry masses coming from the northeast in the Northern Hemisphere and southeast in the Southern.
Trade winds and monsoons are characteristic of tropical areas. They blow year-round from the northeast (above the equator) and southeast (below the equator). A border of several hundred kilometers runs along the equator line between them. Over the oceans they go without deviations, and near land they can change direction under the influence of local conditions.
Monsoons are winds that change direction twice a year. In winter, they come from land, bringing dryness and coolness, and in summer - from the oceans, bringing moisture and rainfall. Monsoons are most characteristic for the tropics of Southeast Asia, but they also reach the coastal regions of the Far East. In a weak form, they reach the south and east of the subtropical regions.
Local winds
Local or local winds are air masses that form within narrow territories. The most famous of them: breeze, bora, foehn, samum, mountain-valley winds, dry wind, mistral, marshmallows, etc. Sometimes they are branches of global flows that have acquired slightly different properties in a particular area.
A breeze arises on the coast of the sea, near lakes and large rivers. It changes twice a day, in the afternoon coming from the side of the reservoir, and in the evening - from land. Its speed rarely exceeds 5 m / s. It often happens in the summer, in mid-latitudes and is clearly visible only on calm days.
Samum appears in deserts from excessive heating of air and lasts up to two hours. It is foreshadowed by the “singing of sand”, after which a sharp barrage and storm begins, carrying hot air and hot sand and dust.
Bora is a strong wind blowing in gusts. It occurs in places where the seashore is surrounded by mountains. The wind appears from the outside of the mountains and, overcoming the obstacle, collapses on the coast with a powerful cold stream. It lasts from one day to a week and can lead to storms and destruction.
Devastating winds
Some winds may have extreme power and strength. They turn settlements into debris, sink ships in the ocean, surging waves. They are not classified according to the area where they appear, but according to their strength and characteristics.
Storms and storms are winds at a speed of 20-32.6 m / s (from 9 to 11 points). They periodically occur in different parts of the world during tornadoes, squalls and cyclones. Squalls are a sharp increase in wind speed and strength in minutes. The wind itself can last several hours and at the same time be accompanied by a dust storm and thunderstorm.
Hurricanes and typhoons occur during tropical cyclones. They are stronger than storms and longer than squalls. In fact, these are the same phenomena, but in America the name "hurricane" is accepted, and in Asia - "typhoon". They are accompanied by showers, the rise of waves. Such winds cause flooding, destroying buildings, lifting up heavy objects and tearing up trees.