Why is it generally good weather near high pressure centers?

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

1. A cyclone is a low-pressure center, and an anticyclone is a high-pressure center.

2. Cyclones generally correspond to convergent rising motion, symbolizing rainy weather; anticyclones generally correspond to divergent sinking motion, symbolizing fine weather.

3. Cyclones can be divided into extratropical cyclones and tropical cyclones. Tropical cyclones can be divided into tropical depressions (the maximum wind force on the ground near the center is less than level 8), and tropical storms (the maximum wind force on the ground near the center is level 8-9). ), severe tropical storms (maximum wind force near the center is level 10-11) and typhoons (maximum wind force near the center is greater than or equal to level 12, and the lowest air pressure at the center sea level is less than 960 hPa).

The following explains why the typhoon center (i.e., the typhoon eye area in professional terms) is a downdraft:

Typhoon temperature field: warm center structure

Horizontal Flow field: From the inside to the outside, there are the typhoon eye area (downdraft, light clouds and light winds), the typhoon vortex area (violent storms, updrafts), and the outer windy area (strong winds, precipitation, and weak updrafts). So generally speaking, typhoons are downdrafts, which does not violate Article 2 above, but creates a special area called the eye of the typhoon.

So why is the eye of a typhoon always a downdraft and a calm, sunny day?

A typhoon is a strongly developing tropical cyclone with extremely low air pressure near the center (Item 3 above, a tropical cyclone with maximum wind force of level 12 or above near the center is called a typhoon). Therefore, it points to the center of the typhoon from all sides. The horizontal pressure gradient force is extremely large, and the resulting wind speed is also extremely large; the greater the typhoon wind speed, the greater the geostrophic deflection force exerts on the horizontal airflow during its movement, so the airflow rotates around the center of the typhoon and rises; however, During the high-speed rotation process, a strong inertial centrifugal force is generated, just like the spin-drying effect of a washing machine, making it difficult for the airflow to reach the center of the typhoon, and the center of the typhoon is a warm center structure, so the air density in the center of the typhoon is smaller; while in the typhoon vortex area and the outer windy area, the airflow rises. After reaching the top, because the density of the central air below is very small, the airflow sinks from high altitude to supplement it. This forms a clear, windless (prevalent downdraft, not horizontal airflow) the eye of the typhoon.