What are the structures and characteristics of typhoons?

The horizontal distribution of various meteorological elements and weather phenomena in a typhoon can be divided into three areas: the outer layer (including the outer cloud belt and the inner cloud belt), the cloud wall area and the typhoon eye area, and the vertical distribution can be divided into the low-altitude inflow layer (below 1 km), the high-altitude outflow layer (above1km) and the middle-level updraft layer (1). There are several spiral rain belts in the corresponding cloud system. The more spiral airflow involved in a typhoon, the faster the tangential wind speed becomes. At a certain distance from the typhoon center, the airflow no longer hovers, so a lot of wet air is forced to rise strongly, forming a towering cloud wall around the center. The top of the cumulonimbus cloud wall can be as high as 19 km, which is the cloud wall area.

In typhoon, the maximum wind speed occurs inside the cloud wall, and the maximum rainstorm occurs in the cloud wall area, so the cloud wall area is the storm area most prone to disasters. When the updraft in the cloud wall area reaches high altitude, due to the weakening of the pressure gradient, a large amount of air is forcibly thrown out, forming an outer layer, and only a small amount of air flows inward into the typhoon center and sinks, forming a clear typhoon center, which is the typhoon eye area. The radius of typhoon eye is about 10 ~ 70km, with an average of about 25km. The release and warming of latent heat in the cloud wall area and the sinking and warming of the typhoon eye area make the typhoon a warm-hearted low-pressure system.

At the lower level, typhoons mainly flow into low-pressure inflow. Because of the angular momentum balance, the inner region can produce strong wind speed, and the outflow airflow of anticyclone is in the upper layer. Strong upward movement connects the upper and lower circulation, which is the main feature of typhoon circulation. The hottest temperature in a typhoon is caused by the sinking movement, which occurs at the inner edge of the eye wall, where there is the strongest sinking movement. Convergence is strongest at the maximum wind speed radius in the lower layer of typhoon, and the maximum wind speed radius does not change much with height, which is located in the eye wall. In addition, the asymmetry of typhoon structure is also a major feature. The analysis shows that there is obvious asymmetry in the inner and outer areas of the typhoon, which plays an important role in the development of the typhoon and the transportation of momentum and kinetic energy.