How many days, minutes and seconds will the great cold in 2020 enter?
During the severe cold solar term, the atmospheric circulation is relatively stable, and the circulation adjustment period is about 20 days. When this circulation is adjusted, there will often be large-scale rain and snow weather and strong winds to cool down. When the west of 80 degrees east longitude is a long wave ridge and East Asia is a coastal trough, sustained low temperature will occur in China under the influence of northwest wind flow control and constantly supplemented cold air. Like slight cold, great cold is also a solar term indicating the degree of cold weather.
According to the statistics of perennial climate data in China, the coldest period of a year in northern China is the middle of June 65438+1October (June 10 -20) of the Gregorian calendar every year. The annual slight cold solar term starts from 65438+1October 5-7, with a solar term of about 15 days, and the middle period is just within the slight cold solar term; Therefore, for most northern regions, slight cold is indeed colder than severe cold.
But for most parts of the south, it is the coldest during the great cold solar term; The severe cold solar term in the south generally starts from 65438+1October 20th, and the end of 65438+1October is the coldest time of the year in the south.
rural activity
In severe cold season, agricultural production needs to master the law of cold and warm changes, pay attention to the forecast of meteorological departments at any time according to different years, different geographical locations and topographic conditions, plant crops reasonably and avoid unnecessary losses.
For example, before introducing new crop varieties, it is necessary to have a clear understanding of the topography, surrounding environment, temperature, precipitation and humidity of the planting area, and to fully investigate and demonstrate whether the introduced varieties are suitable for the local meteorological environment.
Especially in the large-scale introduction of cash crops, it can not be ignored; Small-scale planting should also pay attention to the surrounding terrain and environment. For example, around large reservoirs, due to the temperature regulation of water, freezing damage is often light or non-existent. Before the cold winter comes, we can plant some cash crops and flowers around the reservoir that are easily frozen.
According to the weather changes, the temperature and humidity of greenhouse crops should be well controlled. Both ends of the greenhouse should be ventilated around noon, but they must be closed before 4 pm to maintain the temperature in the greenhouse.