Is it cold in the northeast?

In winter, the northern part of China is very cold, and the lowest temperature drops to MINUS 30-40 degrees Celsius. People have to wear thick cotton-padded clothes or fur coats, and migratory birds have already flown to the south, because the temperature there is mostly above zero, and the lowest temperature is only a few degrees below zero.

The south and the north of our country are on the same earth, in the same atmosphere and under the same sun. Why is the temperature difference so big?

It turns out that the temperature around the earth depends on the amount of solar radiation energy absorbed by the surface and its thermal radiation ability. If the intensity of sunlight is large and the time is long, then the ground will receive more heat from solar radiation and naturally release more heat into the air, so that the temperature will receive less heat from solar radiation and release less heat into the air, and the temperature will naturally be low.

We know that the winter sunshine shines obliquely in the northern hemisphere of the earth instead of directly, which means that the winter sunshine shines obliquely on our land, because China benefits in the northern hemisphere! The degree of inclination of sunlight to the north and south of China is also different. The north is more inclined than the south, and the ground in the north gets less solar heat than the south. In other words, the light intensity in the north is much smaller than that in the south.

In addition, from the perspective of the length of illumination, the illumination time in the south is longer than that in the north in winter. For example, in winter, the illumination time of Hainan Island in China is about two hours longer than that of Heilongjiang. It is precisely because the winter light intensity in southern China is greater than that in the north, and the light duration is longer than that in the north, which leads to the lower temperature in the north and much colder in the north.