Why is the autumn sky so high?

1. After autumn, the sun in the northern hemisphere gradually changes from direct to oblique around the summer solstice, with shorter daytime and longer nighttime. During the day, the ground absorbs less sunlight than in summer, and the water evaporated from the ground into the air is also reduced. ?

2. With the gradual withdrawal of warm and humid air and the gradual entry of cold air, and gradually occupying most provinces and regions in China, the temperature begins to decrease, which will also reduce the evaporation of water vapor on the ground. Therefore, Wan Li has clear skies during the day and stars at night, which makes people feel that the autumn sky is particularly high.

Extended data:

Autumn solar terms

There are six solar terms in autumn, namely beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew and First Frost.

An atmosphere/scene

The temperature will gradually drop in autumn, but it is generally slower than in winter. Due to the difference of dry and wet conditions, there will be cold and rainy weather conditions or dry and cool weather conditions in different regions. In the cold late autumn, due to the large temperature difference between day and night, the water vapor transpiration during the day will condense at night, either dew or frost.

astronomy

In autumn, the direct point of the sun gradually moves south from the northern hemisphere, passes through the equator after the autumnal equinox, and the sun directly shines in the southern hemisphere. Seen from the northern hemisphere, the angle of the sun gradually becomes lower, and the gap between day and night becomes smaller. At the autumnal equinox, the length of day and night is equal. In autumn, the distance between the earth and the sun is from far to near. Seen from the ecliptic plane, the sun is on the background of Leo, Virgo and Libra.

Reference: Baidu Encyclopedia-Autumn