Why is the temperature difference between day and night so big in winter?

The earth's dark hemisphere radiates heat into space. On a clear night, there is no cloud to block the heat, so the temperature will become very low. It is already very low in late autumn and winter, and frost is easy to appear.

Artificial smoke screen can enhance the atmospheric inverse radiation, reduce the heat lost by ground radiation at night, and keep the ground warm, so it can defend against frost.

Reason:

1. This is related to the atmospheric inverse radiation, that is, the atmosphere has the function of heat preservation. The thicker the clouds at night, the stronger the atmospheric inverse radiation and the slower the heat loss; On the contrary, if the night is sunny, the heat preservation effect is poor and the temperature is low, frosting will occur.

2. The old farmer's fire in the field is equivalent to increasing the thickness of the atmosphere, enhancing the inverse radiation of the atmosphere, and playing the role of heat preservation, thus reducing the first frost and mainly protecting crops.

3. If it's sunny day and night, the temperature difference is bigger than cloudy day and night. It is also the heat preservation and weakening effect of the atmosphere.