When is the season with the lowest sun height at noon?
Because of the revolution of the earth, the sun travels between the Tropic of Cancer and the Tropic of Cancer at the direct point of the earth within one year. Take the area where the Tropic of Cancer passes in the northern hemisphere as an example: when the sun shines directly on the Tropic of Cancer in a year, it is the summer solstice solar term in northern China. At noon, the sun is directly above the head, that is, the solar altitude angle is 90, which is the maximum value in a year.
When the sun shines directly on the tropic of Capricorn, it coincides with the solar term of winter solstice in northern China. At this time, the solar altitude angle is 43, which is the minimum value in a year. Due to the rotation of the earth, the apparent motion of the sun (rising in the east and setting in the west), that is, the daily variation of the height of the sun.
Extended data
1. In the area between the Tropic of Cancer, there are opportunities for direct sunlight twice a year, and the height of the sun is the highest at noon, which is 90. There is a minimum when the sun shines directly on the Tropic of Cancer. Among them, except for the two minima of the equator, the other areas are the smallest when the sun shines directly on the Tropic of Cancer.
2. In the area above the Tropic of Cancer, there is an opportunity of direct sunlight once a year, that is, the solstice in summer and the solstice in winter.
3. Outside the Tropic of Cancer, which may include the Tropic of Cancer, the sun is the largest when it is directly on the Tropic of Cancer in this hemisphere, and the smallest when it is directly on the Tropic of Cancer in another hemisphere. For example, Beijing is about 40 north latitude. During the summer solstice in the northern hemisphere, the sun shines directly on the Tropic of Cancer. At this time, the height of the noon sun here is the highest, about 73.5; On the solstice of winter, the sun shines directly on the tropic of Capricorn. At this time, the noon sun height here is the smallest, about 26.5.
Baidu encyclopedia-noon sun height