count of nine days is divided into nine nine days, and each nine day has its own characteristics. At the same time, the weather changes are also different. When is the May 9th time in 2021? What are the specific days of May 9, 2020? Let's get to know it with the old yellow calendar!
What is the time of May 9, 2021? First day: January 26, 2021 second day: January 27, 2021 third day: January 28, 2021 fourth day: January 29, 2021 fifth day: January 30, 2021 sixth day: January 31, 2021 seventh day: February 1, 2021 eighth day: February 2, 2021 ninth day: February 3, 2021 The number nine ofand
in the day (beginning of spring) occurs during the winter solstice. The day is the shortest, the angle between the direct sunlight angle and the ground is the smallest, and the sunshine intensity received by the ground per unit area is the smallest. Therefore, the ground receives the least solar heat every day, and the inverse difference of daily heat budget has not reached the maximum. After the winter solstice, although the daytime increases day by day, the growth rate is very slow. From the winter solstice to the "March 9" period, the average daily growth is only about one minute. At the same time, the angle between the direct sunlight angle and the ground increases very slowly. The daily heat budget of the ground is still in deficit, so it continues to lose heat and the ground temperature continues to decline. The deficit of total ground heat budget reached its maximum in the "March 9th" season. As the air temperature is mainly affected by the ground temperature, it leads to the lowest temperature in the "March 9th" season (not in the whole country, but every year, which varies by region and year). In addition, the cold air mass in Siberia also developed to an extremely strong stage before and after the "March 9th" movement, and the frequent invasion of strong cold air is also one of the reasons for the low temperature.
the coldest period of winter usually occurs after the winter solstice. After the beginning of winter, it means entering winter, which does not mean starting to be cold. Therefore, the heat stored on the surface in the second half of the year still has some energy, so it is not very cold. There is a saying among the people that "October little sunny spring" refers to the sunny, warm and comfortable "little sunny spring" weather during Mengdong. Therefore, in fact, it is generally not very cold in early winter (Mengdong), but with the passage of time, the cold air frequently goes south and the temperature gradually decreases. In winter, the so-called "cold in March and September" is usually not very cold before the winter solstice. The real cold is after the winter solstice, especially "March and September" and "April and September".https://www.dailyq-a.com/Culture/30353.html
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