twenty-four solar terms
Source: internal company
Greater Snow, the 21st of the twenty-four solar terms, is the third solar term in winter, when the sun reaches 255 degrees of yellow longitude, on December 6-8 of the Gregorian calendar each year. The twenty-four solar terms are the products of farming civilization, and the climatic elements affecting agricultural production are mainly precipitation, temperature and light. Like the Light Snow, the Greater Snow is a festival reflecting the trend of changes in temperature and precipitation, and it is a reflection of the farming culture for the festival. Daxue is a festival that reflects the characteristics of climate, and the elements of climate include precipitation, air temperature and light, among which precipitation is an important element of climate. Meteorologically, rain, snow, hail, and other water vapor condensation from the sky down to the ground are called "precipitation". The arrival of the snowy season means that the weather is getting colder and the amount of precipitation is increasing.
Ancient texts say, "Greater Snow is a November festival, when snow is abundant. " As "snow" is a product of cold, representing cold and rainy weather, this festival is characterized by a significant drop in temperature, and strong cold air can often bring rain or snow. The name "Greater Snow" is a metaphor, reflecting the climate change during this festival period, with active cold spells, decreasing temperatures and increasing precipitation, and is not meant to indicate that a lot of snow falls during this festival period. However, the weather gets colder and colder after the snowy season, and the likelihood of snow increases dramatically. There is no necessary connection between "Greater Snow" in the sense of the festival and "great snow", which describes the amount of snowfall in weather forecasts. The "Greater Snow" is a climatic concept, and it represents the climatic characteristics during the Greater Snow period. The "heavy snow" in the weather forecast refers to snowfall with greater intensity. Meteorological regulations: when it snows, visibility is very poor, the horizontal visibility distance is less than 500 meters, the depth of snow on the ground is equal to or greater than 5 centimeters, or the amount of snowfall in a 24-hour period of 5. 0 to 9. 9 millimeters between the snowfall is called heavy snow.
The "Greater Snow" is a festival that reflects the characteristics of the climate. It is characterized by a significant drop in temperature and an increase in precipitation compared to autumn and early winter. At the time of the snow, most of China has entered the cold winter, the lowest temperature in some areas of the north have fallen to 0 ℃ or below. Precipitation (rain or snow) increases in areas where strong cold air fronts warm and cold air. Meteorology will rain, snow, hail and other water vapor condensation from the sky down to the ground are called "precipitation".
The meaning of the Greater Snow is different from the weather snow. In fact, the snow of Greater Snow but often not as big as the snowy season, the year's snowiest season is not in the snowy, snowy season. For example, in the middle and lower reaches of the Yellow River, the largest annual snow festival, neither "Greater Snow", more not "Light Snow" (because then the temperature is lower, less water vapor in the atmosphere), but in the spring "The Rains"!It is the "rain" season in spring. The amount of snowfall is not the greatest during the Greater Snow season. The reason for this is similar to the fact that the snow is heavier than the heavy snow. That is, late February has passed the coldest period of the year, the early spring weather, the southern warm air began to be active, water vapor began to be rich, and at this time the northern cold air is still strong, strong confrontation, warm air in the back of the density of the cold air flow strong, long-lasting rise, so it may fall heavy snow.
Ancient Chinese people categorized heavy snow into three seasons: it is said that at the first time because of the cold weather, the chilling bird is no longer chirping; at the second time is the most prevalent yin gas, the so-called peak and decline, the yang gas has been sprouting, the tiger began to courtship behavior; "Li" for the Aster indicus L., it is said to be able to feel the sprouting of yang gas and draw out the new shoots.
Agriculture is the foundation of the world. Farming refers to agricultural work, and farming time refers to the timing of farming, according to the agricultural time to do farming, will achieve twice the result with half the effort. Due to the great difference in climate characteristics between the north and the south of China, accordingly, the main agricultural activities in the north and the south are also different. Winter in the northern region of a blanket of ice, snow, basically no way to plant crops, at this time the northern region of field management is also very little, is the idle season. Southern areas of wheat, rape and other crops are still growing slowly, strengthening the field management of spring flowering crops is very important. During Greater Snow, there will often be cooling, blizzard, freezing rain, freezing fog, streaming and other weather disasters. If frost damage, but also timely loosening of the soil to increase fertilizer, water storage and warming, and strengthen the middle and late management, and strive to minimize frost damage losses.
(resource: Baidu Encyclopedia)