The difference between strong tropical storms and typhoons
1, severe tropical storm
Strong tropical storm is a kind of tropical cyclone, and the continuous wind force near its center is 88- 1 17 km per hour, that is, the wind force of storm level. Tropical storms form on the sea in tropical or subtropical areas.
Tropical storm is a warm core structure developed from the latent heat released by steam cooling and solidification. So when a tropical storm lands, or when a tropical storm moves to a low-temperature ocean. It will weaken and dissipate due to the loss of warm and humid air supply energy, or lose the characteristics of tropical storms and become an extratropical cyclone.
The most destructive of all natural disasters. Every year, hurricanes sweep inland from the ocean, leaving only a mess after strong winds and storms. Tropical storm is a kind of typhoon, which refers to a typhoon with the maximum wind force at the center of -9 (17.2-24.4m/s).
2. Typhoon
Typhoons often bring strong winds, heavy rains and storm surges. Typhoons usually form in tropical areas (such as the North and South Pacific, the North Atlantic and the Indian Ocean) 3-5 latitudes away from the equator, and their movements are mainly affected by large-scale weather systems, and eventually dissipate at sea, or degenerate into temperate cyclones, or dissipate after landing.
Typhoons with winds above 12 are divided into three grades, while hurricanes have more grades and higher upper limits. A first-class hurricane is equivalent to a typhoon or a strong typhoon, a second-class hurricane is equivalent to a strong typhoon, a third-class hurricane is equivalent to a strong typhoon or a super typhoon, and a fourth-class hurricane and a fifth-class hurricane are equivalent to a super strong typhoon.
In China, tropical cyclones in the northwest Pacific are classified into six grades according to the maximum average wind force near the bottom center, in which the wind force is 12 or above, which is collectively called "typhoon". Typhoon can be divided into general typhoon (maximum wind 12- 13), strong typhoon (maximum wind 14- 15) and super typhoon (maximum wind ≥ 16).
The formation of severe tropical storms and typhoons;
1, severe tropical storm
To have a wide enough tropical ocean surface, this ocean surface requires not only that the surface temperature of seawater is higher than 26.5℃, but also that the water temperature exceeds this value in a layer of seawater 60 meters deep.
The strong wind rotating around the tropical cyclone will cause the sea water to churn around the center, even in the typhoon center where the air pressure drops very low, the sea surface will swell and then spread around, so the sea water will churn around from the typhoon center.
In a typhoon, this sea churning phenomenon can affect the depth of 60 meters. On the ocean surface where the seawater temperature is lower than 26.5℃, it is difficult to maintain a typhoon due to insufficient heat energy. In order to ensure that the sea surface temperature is always above 26.5℃ during this tumbling process, this warm water layer must have a thickness of about 60 meters.
2. Typhoon
The sea surface water temperature is above 26.5℃; Initial disturbance of a positive vorticity; The shear of ambient wind in the vertical direction is very small; Low pressure or cloud disturbance is at least several latitudes from the equator.
The initial stage of typhoon is tropical depression, and it usually takes about 2 days from the initial low-pressure circulation to the maximum average wind force near the center, only three or four days for the slow one and only a few hours for the fast one. In the development stage, the typhoon continuously absorbs energy until the central air pressure reaches the lowest value and the wind speed reaches the maximum value. After the typhoon landed, under the joint influence of ground friction and insufficient energy supply, it will quickly weaken the death.
Baidu Encyclopedia-Severe Tropical Storm
Baidu Encyclopedia-Typhoon