Snow surface has a high reflectivity (about 0.9) to solar radiation and a high absorption rate (up to 0.99) to infrared radiation, which explains the ground.

In fact, your problem stem is the key to solve the problem. The two main reasons for the cold weather on the ground are the two points mentioned in the title. One is that the snow surface reflects a lot of solar radiation, making it impossible for heat to remain near the ground. The other is that the infrared radiation that carries a lot of heat energy in the part where the solar radiation reaches the ground is absorbed by the snow surface (under the sunlight, the heat energy is mainly distributed in the red and infrared bands), so it is conceivable that there is such a large mirror that it will reflect light and absorb heat on the ground in snowy days.