Be alert to the trend of typhoons, pay attention to listening to media reports or learn the latest situation of typhoons through meteorological consultation telephones and meteorological websites. When the typhoon comes, close the doors and windows to prevent it from raining, and remove the flowerpots on the windowsill or balcony to prevent them from falling. After the typhoon warning is issued by the Meteorological Observatory, don't go to the area where the typhoon passes or swim on the beach, let alone sail out to sea.
Cyclones go through many stages and their intensity will change constantly. It may reach the land after strengthening and weakening, and then return to the ocean and become stronger again. The formation of a typhoon requires a large area of quiet and warm ocean. The surface temperature of the ocean exceeds 26.5 degrees Celsius and lasts for a period of time before warm air can be formed above the surface of the ocean.
Typhoons also need low-level winds. When the air in the ocean is heated, it will expand and become lighter, and then rise. Other winds blow into the rising air and will rise when heated. Generally speaking, the rising air contains water evaporated from the ocean surface. When it rises, it cools and condenses to form a large number of clouds, which can reach a height of about ten kilometers.
Warm air enters and rises, and is attracted by the airflow above, bringing water into the upper atmosphere and thickening the clouds. The latent heat in water vapor can be released by condensation, which provides more power for cyclone and forms a self-sustaining thermal cycle. By releasing new energy, the clouds rise further, and the height can reach 12 to 15 km.
The Coriolis effect produced by the earth's rotation makes the updraft around the typhoon center spiral up, the cyclone matures to form a storm eye, the rising air cools down and forms a bright and calm eye, in which the cyclone burns angrily.
The eye wall is the strongest part of the typhoon, like a rotating cylinder. Cyclones in the southern hemisphere rotate clockwise and cyclones in the northern hemisphere rotate counterclockwise. The center of tropical cyclones usually has the lowest air pressure, about 950 mbar or lower, while the average air pressure on the earth's surface is about 1000 to 10 10 mbar.
Because of the low pressure of typhoon, the wind is strong, and the greater the pressure difference, the greater the wind. After the cyclone is formed, it will be carried away by the global wind circulation and its source will gradually expand. Warm current will make cyclones absorb heat and water continuously.
Typhoon (English: Typhoon) is a tropical cyclone. Tropical cyclone is a low-pressure vortex that occurs on the surface of tropical or subtropical ocean, and it is a powerful and profound "tropical weather system". In China, tropical cyclones in the northwest Pacific are classified into six grades according to the maximum average wind speed near the center of the surface layer, and the wind force near the center reaches 12 or above, which is collectively called typhoon.
Typhoons often bring strong winds, heavy rains and storm surges, which not only bring disasters to human beings, but also bring benefits to human beings. Typhoon has brought abundant fresh water resources to human beings, which is of great significance for improving fresh water supply and ecological environment.
In addition, typhoons also keep the global cold and heat relatively balanced; The climate in the equatorial region is hot. If the typhoon does not disperse this heat, the tropics will be hotter, the frigid zone will be colder and the temperate zone will disappear from the earth.