How is lightning formed? What's the difference between thunderstorm and general lightning?

Lightning is the natural discharge of Lei Yun (charged cloud) to buildings and the earth, which will cause serious damage to buildings or equipment. Therefore, we should understand the formation process of lightning and its discharge conditions, so as to take corresponding measures for lightning protection of buildings.

When the weather is hot and humid, the water on the ground is heated and turned into steam, which rises with the heated air on the ground and meets the cold air in the air, so that the rising water vapor condenses into small water droplets and forms cumulus clouds. The water droplets in the cloud are blown by the powerful airflow and split into small water droplets and large water droplets, and the larger water droplets are positively and negatively charged. Tiny water droplets gather with the wind to form a negatively charged Lei Yun; Larger water droplets with positive charges often fall to the ground to form rain or are suspended in the air. Due to electrostatic induction, negatively charged Lei Yun induces a positive charge on the earth's surface. Thus, a large capacitance is formed between Lei Yun and the earth. When the electric field intensity is very strong and exceeds the breakdown intensity of the atmosphere, a discharge occurs between Lei Yun and the earth.

Thunderstorm is a local convective weather accompanied by lightning strike and lightning. They must be generated in strong cumulonimbus clouds, so they are often accompanied by strong showers or heavy rains, and sometimes hail and tornadoes, belonging to a strong convective weather system. Cumulonimbus clouds that form thunderstorms develop vigorously, and there are often ice crystals on the upper part of the clouds, which make the clouds generate charges. The charge distribution in the cloud is very complicated. The upper part of the cloud is dominated by positive charges, and the middle and lower parts of the cloud are dominated by negative charges. There is also a small positive charge region in the strong updraft in front of the lower part of the cloud. Therefore, a potential difference is formed between the upper and lower parts of the cloud. When the potential difference reaches a certain level, lightning will occur. In the process of discharge, the temperature in the flashover suddenly rises, which makes the air volume expand rapidly, thus generating shock waves and leading to strong lightning. When a discharge can sometimes form between clouds, it is called lightning strike. Therefore, thunderstorm is the product of atmospheric instability, and it is the general name of cumulonimbus clouds and their accompanying disastrous weather. The duration of thunderstorms is generally short, and the life history of a single thunderstorm is generally less than 2 hours. There are more thunderstorms in the south of China than in the north, and there are more thunderstorms in the mountains than in the plains. They occur in summer and autumn, only occasionally in winter in southern China. Thunderstorms occur in the afternoon. At night, they are cooled by cloud top radiation, which makes them in the clouds.