How many grades are there in the wind?

In meteorology, at present, it is generally divided into twelve grades according to the magnitude of wind power:

Level 0 wind is also called no wind.

1 The wind is called soft wind, and the smoke shows that there is no water drop at the microwave peak of the wind direction.

Level 2 wind is called breeze, the leaves are slightly noisy, and people feel windy.

The third-grade wind is called breeze, with standard diffusion and broken peaks.

Level 4 wind is called breeze, and the twigs of trees shake, which can blow up dust and paper on the ground.

Level 5 wind is called strong wind, and young trees sway in waves and foam peaks.

The 6-level wind is called strong wind, the branches are shaking, the wires are whistling, and it is difficult to walk with an umbrella.

The 7-level wind is called gale, so it is difficult to walk.

Level 8 wind is called strong wind, and the twigs of trees can be broken, which makes people walk against the wind and has great resistance.

Grade 9 wind is called gale, and the peaks of small houses are all rolled back.

10 wind is called gale, which is rare on land. Trees can be pulled up and buildings are seriously damaged.

1 1 The wind is called a storm, and the damaged peaks are all water drops.

Winds above 12 are called typhoons or hurricanes, which are extremely destructive and rarely seen on land.

In fact, in nature, the wind sometimes exceeds 12. For example, the central wind force of a strong typhoon or tornado may be much larger than the magnitude of 12, but the wind above the magnitude of 12 is rare, so the magnitude is generally not specified.

In the weather forecast, we often hear the expression "the north wind is 4 to 5", in which the wind refers to the average wind; If you hear the expression "gust 7", gust refers to the wind with high and low wind speed, and the wind at this time refers to the maximum wind force.

The magnitude of wind speed is often expressed by several winds. The level of wind is determined according to the degree of influence of wind on ground objects.

Graded ballad

Zero-level windless cooking smoke; The first-class soft wind smoke is slightly inclined;

The leaves of the second breeze ring; Three-level breeze swaying branches;

Level 4 gale dust; Five-level breeze waves;

Six-level strong wind shakes trees; Seven winds are difficult to walk;

The branches of the eight-strong wind are broken; Nine-level gale chimney was destroyed;

Ten-level gale uprooting; Eleven storm lands are rare;

12 hurricane has terrible waves.

Historical origin

In the Tang Dynasty more than 1000 years ago, our people not only recorded weather phenomena such as rain and snow, but also measured the wind. At the beginning of the Tang dynasty, an accurate instrument for measuring wind speed was not invented, but at that time, the moving speed of wind could be calculated according to the characteristics of wind to objects, and the wind grade could be determined. There is such a record in Li's "Phenomenon Play Zhan": "The moving leaves are ten miles, the songs are hundred miles, the branches are two hundred miles, the leaves are three hundred miles, the dead branches are four hundred miles, the big branches are five hundred miles, the stones are three thousand miles." This is to estimate the wind speed according to the influence of wind on trees. "moving leaves for ten miles" means that the leaves are slightly fluttering and the wind speed is ten miles a day; What "sings" is the rustling of leaves, and the wind speed at this time is hundreds of miles a day. In addition, some wind grades are determined according to the symptoms of trees, such as "first-class moving leaves, second-class ringing, third-class shaking branches, fourth-class falling leaves, fifth-class broken branches, sixth-class broken branches, seventh-class broken trees, flying sand and stones, and eighth-class uprooting". These eight winds, plus "no wind" and "gentle wind" (when the wind comes, it is cool and gentle, so it is called gentle wind), which can be combined into ten levels. The grades of these winds are not much different from those imported from abroad. This can be said to be the earliest wind level in the world.

More than 200 years ago, there were no instruments for measuring the magnitude of wind, and there were no unified regulations. Every country expresses itself in its own way. At that time, there was a man named beaufort in England. He carefully observed the situation of various objects on land and at sea in different winds, and accumulated 50 years of experience before he divided the wind into 13 in 1805, which is also commonly known as Beaufort wind scale. Later, after research and supplement, the original explanation was explained more clearly, and the speed of each wind level was improved, which became the "jargon" for forecasting wind power now.