The winter of this year was extremely cold in Dalian, Liaoning Province, and some people noticed that the sea near Dalian appeared to be smoking hot despite the weather being clearly cold.

Dalian Ocean University, Marine Science and Technology and Environmental College Professor Song Jun said, this phenomenon is called evaporative fog. Due to the high temperature of seawater, the evaporated water vapor will be supersaturated when it meets colder air, and water molecules will precipitate out. If there are condensation nuclei, water droplets or ice crystals will be formed to float in the air. Therefore, there are two necessary conditions for this phenomenon, first, the seawater and the air at the surface should have a temperature difference of more than 15 ℃, and the air is colder than the seawater, so this situation is usually accompanied by a windy process. Second, with condensation nuclei.

On November 14, the first freezing fog landscape of this winter appeared in Jilin Province. Many people think that freezing fog is a phenomenon unique to the northeast, but in fact, it also occurs in many areas in southern China, such as the alpine areas of Chongqing, Guizhou, Guangxi, Anhui and other places.

Yun Tian, a senior engineer at Jilin Meteorological Bureau, said that fog freeze is mainly formed by ice crystals on objects with temperatures below freezing point as the white opaque grain-like structure of deposits. It is formed by the process when supercooled water mist, that is, water mist with a temperature lower than 0°C, collides with an object that is also lower than the freezing temperature, then freezing fog is formed.

Cold weather also affects rivers, and as the temperature drops, rivers can also experience ice run dates. Ice run date is the flow of ice and river water together before the river freezes over. It is crystal clear and looks beautiful, but it is also a hidden danger. Once the flooding starts, it will form a disaster, the flooding will be sudden, destructive and difficult to prevent and control.

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