What is the concept of a three-level typhoon?

What is the concept of a three-level typhoon?

The third-class typhoon gently shakes the branches, and when the wind blows, the red flag will fly in the air. In fact, the third-level wind is not a typhoon, but a breeze; In China, tropical cyclones in the South China Sea and the Northwest Pacific are classified into six grades according to the maximum average wind force near the bottom center, and those whose wind force reaches 12 or above are called "typhoons".

Typhoon is a kind of tropical cyclone. Tropical cyclone is a low-pressure vortex that occurs on the surface of tropical or subtropical oceans, and it is a powerful and profound "tropical weather system". Broadly speaking, the word "typhoon" is not the intensity of tropical cyclones. Tropical cyclones (including tropical storms, severe tropical storms and typhoons defined by the World Meteorological Organization) with sustained wind speeds of17.2m per second are called typhoons.

According to the National Standard for Tropical Cyclone Grades (GBT 1920 1-2006) issued by China Meteorological Bureau, tropical cyclones are divided into six grades according to the maximum surface wind speed near the center, namely tropical depression, tropical storm, strong tropical storm, typhoon, strong typhoon and super typhoon. The maximum wind speed of tropical depression is 6-7 (10.8 ~17.1m/s), the maximum wind speed of tropical storm is 8-9 (17.2 ~ 24.4m/s), and the maximum wind speed of typhoon is/kloc-0.

From the first edition of the wind-level ballad: "On the zero-level windless kitchen smoke, the first-level soft wind smoke is slightly inclined;" The leaves ring in the second breeze, and the branches shake in the third breeze; Four levels of wind and dust, five levels of breeze and water; The six-level strong wind shakes the tree, and the seven-level wind is difficult to walk; The branches of the eighth-level gale are broken, and the chimney of the ninth-level gale is destroyed; Ten-level storms are uprooted, and eleven-level storms are scarce; It can be seen that the third-class typhoon belongs to the breeze.