Calculation of gale level

Wind speed refers to the horizontal distance of air flow per unit time. According to the phenomenon caused by the wind to the ground objects, the wind is divided into 13 grades, which are called wind grades. . The "East Wind Level 3" that people usually hear in the weather forecast refers to the "Beaufort Wind Level". "Beaufort Wind Scale" is a wind scale determined by Francis Beaufort in England in 1805 according to the influence degree of wind on objects on the ground (or at sea), and * * * is divided into 0~ 17.

Note: The wind speed listed in this table refers to the wind speed value at10m above the flat ground.

Intuitive ballad

Wind speed songs are generally written to let kindergarten children and primary and secondary school students remember the characteristics of wind power levels. Through the wind speed song, you can know the intuitive impression of the wind level. The following is one of them:

Zero wind, straight smoke; The first grade wind, the smoke is slightly biased;

Secondary wind, leaves ring; The third wind, the flag fluttering;

Four winds, dust; Five winds and waves;

Six winds, big trees shake; Seven winds, difficult to go;

Eight winds, broken branches; Nine winds, the chimney collapsed;

Ten winds, uprooted; Xi. Scarcity of land;

Twelve grades, even less, the wind roared and the waves were high.