What are the distribution characteristics of winter temperature in China, and what are the main factors that cause this characteristic?

Main characteristics of winter temperature distribution in China;

In China, there is a great difference in winter temperature between the north and the south. In winter, the sun shines directly in the southern hemisphere. The height of the sun at noon in the north is lower than that in the south, and the length of a day is shorter than that in the south, so the height of the sun is less than that in the south. At the same time, the winter wind aggravated the cold in the north. The lowest temperature in winter in China appears in Mohe area in northern Heilongjiang.

In winter, Chinese mainland is mainly controlled by polar continental air mass or denatured polar continental air mass. At the height of 80~90 degrees east longitude, most of them are high-pressure ridges, while the coastal height is often large troughs. The cold air behind the front ridge goes south continuously, which strengthens the cold high pressure on the ground (Mongolian high pressure), and the warm ocean is mostly controlled by low pressure. The airflow constantly flows from the high pressure area to the low pressure area, which makes the northwest wind, north wind and northeast wind prevail in the lower troposphere in winter in China. The polar continental cold high and its accompanying polar front or sub-cold front are the main weather control system in winter in China, and the weather and climate are characterized by less precipitation, low temperature and dryness. Especially the cold wave or strong cold air weather process, which lasts for a long time, has a large influence range, is harmful to industrial and agricultural production, and the wind cools down.