Is the coldest time of the day in winter late at night or early in the morning?
With the continuous weakening of solar radiation, at a certain moment, when the heat gained by the ground is less than the heat lost by the ground radiation, that is, when the heat on the ground changes from surplus to loss, the ground temperature will reach the maximum value within one day. It's about 13 in the afternoon.
Next, the ground will transfer heat to the atmosphere through radiation, convection, turbulence, etc., which still needs a process, so the temperature will not reach the highest until about 14 in the afternoon.
Therefore, the highest temperature in a day appears in the afternoon 14. After 14: 00, the solar radiation gradually decreases, and the ground temperature drops, so does the temperature. After sunset, there was no solar radiation income, only heat expenditure, and the ground temperature continued to decrease until around sunrise the next day, when there was solar radiation income again, and the temperature reached the lowest value of the day.
Extended data:
Every year between 65438+1October 5-7, the sun is located at longitude 285. It's a slight cold. For China, a slight cold marks the beginning of the coldest day of the year. According to China's meteorological data, slight cold is the lowest temperature solar term, and the temperature of great cold is lower than slight cold in only a few years.
The temperature change of the earth in a day or a year has nothing to do with the distance between the sun and the earth, but with the angle between the sunlight and the ground level. At noon 12, the solar altitude angle is the largest, and the equivalent solar radiation passes through the shortest atmosphere, is weakened by the atmosphere at least, and reaches the ground at most. At the same time, the solar radiation is strongest at 12, because the solar altitude angle is the largest, the area affected by the same amount of solar radiation is the smallest, and the solar radiation per unit area is the most on the ground.