Cyclones and counter-cyclones

Cyclone transit, low pressure control, rainy weather, typhoon disaster; Tropical cyclone

Anti-cyclone transit, high pressure control, sunny weather, crisp autumn, cold wave in winter and drought in summer.

Cyclone:

The ground is uneven in heat and cold. When the ground is hot in a certain place, the air expansion density becomes smaller, so the air flow rises, forming a low pressure near the ground, and the relative air pressure around it is high, so the air flow flows from high pressure to low pressure, that is, from the periphery to the center (the center rises) to form a cyclone.

Because the ground temperature is higher than the high altitude, the temperature drops gradually during the air rising, and the water vapor is easy to be supersaturated (due to the low temperature, the solubility of water vapor in the air is reduced), so it is easy to condense clouds and cause rainfall. So cyclones are prone to rainy days.

Cyclone prevention:

Because of the high ground temperature in the sky, the temperature rises gradually during the air sinking, and the water vapor is not easily supersaturated (because the solubility of water vapor in the air increases due to high temperature), so it is not easy to condense clouds and cause rain. Therefore, the anticyclone is sunny.

Extended data:

1, cyclone:

The horizontal airflow in the atmosphere is a large vortex rotating counterclockwise (clockwise), radiating from all sides to the center, counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. At the same height, the air pressure in the center of the cyclone is lower than that around it, which is also called low pressure. Cyclones are similar to circles or ellipses, and their sizes vary greatly. Small cyclones have a horizontal scale of several hundred kilometers, and large ones can reach three or four thousand kilometers.

The cyclone vertical airflow rises, and the rain is continuous. The typhoon that affects the southeast coastal areas of China in summer and autumn is a kind of cyclone. In cyclones, the weather often changes dramatically, which is the weather system that people are most concerned about and studied at the earliest. Usually classified according to the main areas or thermal structures where cyclones are formed and active.

According to the region, it can be divided into temperate cyclone, tropical cyclone and polar cyclone vortex According to the thermal structure, it can be divided into cold air rotation and hot low pressure. When a place is controlled by low pressure, rainy weather often occurs; When a place is controlled by high pressure, sunny weather often occurs. ?

2. Anti-cyclone

Anti-cyclone is a large-scale air vortex occupying three-dimensional space. In the northern hemisphere, the airflow in the anticyclone area rotates clockwise from the center to the outside and counterclockwise in the southern hemisphere. In the weather map, the anticyclone is a high-pressure area where the isobar is closed and the pressure value decreases from the center to the outside, so it is also called high pressure.

In the surface weather map, the range of anticyclone is represented by the outermost closed isobar. Its horizontal range is much larger than that of cyclone. When it is strong, it can often be compared with the whole continent or ocean, and small anticyclones are hundreds of kilometers. The intensity of anticyclone is expressed by the central pressure value. The higher the central air pressure, the stronger the anticyclone force.

The air pressure at the surface anticyclone center is generally 1020 ~ 1030 hectopascals, and the air pressure at the center of the strongest anticyclone can reach 1080 hectopascals. The intensity of anticyclone changes with time.

Baidu encyclopedia-cyclone and anticyclone