Typhoon is a tropical cyclone, why is its central pressure low?

First of all, you must first understand and master the following knowledge:

1. Cyclone is the center of low pressure and anticyclone is the center of high pressure.

2. Cyclones generally correspond to convergence and upward movement, symbolizing rainy weather; Anti-cyclones generally correspond to divergent and sinking movements, symbolizing sunny weather.

3. Cyclones can be divided into temperate cyclones and tropical cyclones, as well as tropical depression (the maximum wind force near the center is less than 8), tropical storm (the maximum wind force near the center is 8-9), strong tropical storm (the maximum wind force near the center 1 0-1) and typhoon (the maximum wind force near the center1)

The following explains why the typhoon center (technically called the eye of the typhoon) belongs to the downflow:

Typhoon temperature field: warm center structure

Horizontal flow field: from inside to outside, it is typhoon eye area (downward flow, less clouds and light wind), typhoon vortex area (storm and updraft) and peripheral gale area (strong wind and precipitation, updraft, weak). So generally speaking, the typhoon flows downward, which does not violate the second item above, but only produces the special area of typhoon eye.

Then, why is the eye of the typhoon flowing downwards in calm and sunny weather?

Typhoon is a tropical cyclone with strong development, and the air pressure near the center is extremely low (in the third item above, tropical cyclones with maximum wind force 12 or above near the center are called typhoons), so the horizontal pressure gradient force from all directions to the typhoon center is extremely great, and the resulting wind speed is also extremely high; The greater the typhoon wind speed, the greater the influence of geostrophic deflection force on the horizontal airflow movement, so the airflow rotates and rises around the typhoon center; However, in the process of high-speed rotation, strong inertial centrifugal force is generated, just like the drying effect of washing machine, which makes it difficult for airflow to reach the typhoon center, which is a warm center structure, so the air density in the typhoon center is small; However, in the typhoon vortex area and the peripheral gale area, the airflow rises, and after reaching the top, due to the low air density in the center below, the airflow sinks from the air to supplement, thus forming a clear windless typhoon eye (prevailing downward airflow instead of horizontal airflow).

High school geography seems to have an explanation. See Resources.