In winter, the lowest temperature in northern China usually drops to -40 ~ 30 ° C, and everywhere in the field is covered with dense snow. In contrast, the South’s temperature is all 0 ° C or above, and the minimum temperature is not below zero. In summer, the temperature difference between the North and the South is very small; what is the rule?
Because the temperature elevation in Earth’s air is determined by the amount and intensity of solar radiation absorbed by the Earth’s surface, it is more or less strong or weak. If the light shines with a strong intensity for a long time, the Earth’s surface will receive a large amount of heat from the Sun’s rays, and at the same time cause the amount of heat in the air to be emitted will also be much, the temperature is zero. The gas will rise; otherwise, the air temperature will drop.
In the Northern Hemisphere of China, the Sun is often shining in winter; all of it is tilted. Due to the varying degrees of the Sun’s inclination-slanting degrees, some areas in the North are more inclined than in the South. The amount of heat from the Sun per unit area of the ground in the North, Obtained less than in the South, also to say, the light intensity in the North is weaker than in the South of China.
From the perspective of the length of the lighting time, in winter, the lighting time in a day is longer in the South than in the North. For example, during winter, the lighting time in Haikou City, Hainan Province, is about 10.9 hours a day, but in Harbin City, Heilongjiang Province, it is only about 8.6 hours a day. In contrast, in summer, the lighting time in the North is longer than in the South. For example, during the summer, Harbin daytime is about 15.7 hours long, while Haikou is only about 13.2 hours.
On the other hand, in winter, the North is often affected by the airflow of the North, bringing cold weather in the far latitudes; In the South, there is very little airflow like in the North, so the temperature is still relatively high. But in summer, the Southeast monsoon is active in the South, can also bring warm winds blowing from the South to the North.
Thereby, in winter, the light intensity in the South is stronger than in the North. The lighting time is long; this makes the temperature between the North and the South very different. In summer, although the light in the South is stronger than that in the North, but the lighting time is shorter than the North, and there is also an active Southeast monsoon, which can continue to blow up to the North. This also reduces the temperature difference between the two seasons. So the temperature difference in summer between the two South and North China is relatively small, so every year in summer, in Heilongjiang province, farmers can still grow rice as usual.