What is the climatological significance of light snow?

Every year from June 22nd to 23rd in Gregorian calendar (1 1), when the sun reaches 240 degrees of the yellow meridian, it is a light snow with 24 solar terms. Light snow, as its name implies, indicates the time and degree of snowfall.

As the "Twenty-four Solar Terms" said: "In mid-October, it rained and the cold was thin, so it condensed into snow. The words of the villain are not prosperous. " During this period, the weather gradually became cold, and the average first snow period in the middle and lower reaches of the Yellow River basically coincided with the light snow season. Although it began to snow, the amount of snow was generally small, and the night was frozen and the day turned. If the cold air is strong and the warm and humid airflow is active, it may snow heavily. For example, from1993165438+10/0 to 20, some areas in the north experienced heavy snowstorms.

Around the light snow, agricultural production in most areas of China began to enter the period of winter management and farmland water conservancy capital construction. The north wind is blowing and snowflakes are floating, and the area north of the Yellow River has reached Mengdong. At this time, there will be snowfall in northern China. Although the amount of snow is not large, it reminds us that it is the season when it is warm and cold. Before and after the light snow solar terms, the weather is usually cold and gloomy, and people's mood will also be affected by it at this time, especially those who suffer from depression are more likely to aggravate their illness, so in such solar terms, we must learn to regulate our emotions.

"Xiaoxue" coincides with the Gregorian calendar 165438+ the second half of October of the lunar calendar. "Light snow" is a solar term reflecting weather phenomena. The ancient book "Qunfangpu" said: "A light snow will snow when it is cold, but the ground is not cold and the snow is not heavy." That is to say, due to the cold weather, in the "light snow" solar term, the form of precipitation changed from rain to snow, but at this time, because the ground is not very cold, the amount of snow is still limited, so it is called light snow.

With the arrival of winter, the climate turns cool, not only the dew on the ground condenses into frost, but also the rain in the sky turns into snowflakes. After the snow fell, the earth was wrapped in silver. However, because the weather at this time is not too cold, the snow is often half frozen and half melted, or melts immediately after landing, which is called "wet snow" in meteorology; Sometimes it rains and snows together, which is called "sleet"; There are sometimes white ice particles as big as rice grains, which are called "rice snow". The precipitation in this solar term is still relatively scarce, which is far from meeting the demand of winter wheat. There is more fog in the morning than in early winter.

Light snow indicates the beginning time and degree of snowfall. Snow is a sign of cold weather. Light snow solar terms, the northern part of the southern region began to enter winter. "Lotus has no shelter from the rain, but chrysanthemums still have branches in Ao Shuang", which is the scene of early winter. Because the Qinling Mountains and Daba Mountain in the north blocked the invasion of cold air, the power of the cold wave decreased, leading to an obvious "warm winter" in South China. The number of snowfall days in the whole year is mostly less than 5 days, which is much less than that in the middle and lower reaches of the Yangtze River at the same latitude. It is unlikely that snow will fall before the heavy snow. Even in the dead of winter, it is rare to see the charming scenery of "blowing open the petals of ten thousand pear trees"

Because the surface temperature in South China is often above 0℃ in winter, it is more difficult to snow than to snow.

Sometimes, although the sky is "very busy", there is no "broken jade" on the ground. In the cold northwest plateau, snow usually starts at 65438+ 10 all year round. The number of snowfall days in the northwest of the plateau can reach as many as 60 days, and some alpine regions may have snowfall all the year round.