When does it snow? What month? What day? 2023

The time of snow in 2023 is 65438+February 7.

Snow is a natural phenomenon. The water vapor in the air condenses and then falls to the ground again. Water is the foundation of all kinds of life on the earth. The change and movement of water created our world today. On the earth, water is constantly circulating. The water in the ocean and on the ground is heated and evaporated into the sky, and the water vapor moves to other places with the wind. When they encounter cold air, they form precipitation and return to the earth's surface.

There are two kinds of precipitation: one is liquid precipitation, which is rain; The other is solid precipitation, which is snow or hail.

In summer, in mountainous areas, there are often many supercooled water droplets frozen around the crystal nucleus in the sky, forming a white, dull round particle. Meteorology calls this kind of thing graupel, and in many places, it is popularly called Smiling or Snow Graupel. The diameter of graupel is generally between 0.3 and 2.5 mm, which is brittle and easy to crush. Graupel does not belong to the category of snow.

Formation mechanism

One condition is that water vapor is saturated. The maximum amount of water vapor that air can hold at a certain temperature is called saturated water vapor, and the temperature at which air reaches saturation is called dew point. When saturated air is cooled to a temperature below the dew point, the excess water vapor in the air becomes water droplets or ice crystals. Because the saturated water vapor content on the ice surface is lower than that on the water surface, the water vapor saturation required for the growth of ice crystals is lower than that of water droplets.

That is to say, water droplets can grow only when the relative humidity (relative humidity refers to the ratio of the actual vapor pressure in air to the saturated vapor pressure of air at the same temperature) is not less than 100%; As for ice crystals, they tend to grow when the relative humidity is less than 100%. For example, when the temperature is -20℃ and the relative humidity is only 80%, ice crystals can grow. The lower the temperature, the less humidity is needed for the growth of ice crystals. Therefore, in the high-altitude and low-temperature environment, ice crystals are more likely to be produced than water droplets.