China is a vast country with a long distance between the north and the south. Affected by the cold high pressure in Mongolia and Siberia in winter in the north, cold air often goes south to form a cold wave, which greatly reduces the temperature. Therefore, in winter, we should pay more attention to cold and warmth, strengthen exercise and maintain health.
The cause of wind
Wind is a kind of air flow phenomenon on the earth, which is generally caused by solar radiation heat. Sunlight shines on the earth's surface, causing the surface temperature to rise, and the surface air to expand and become lighter and lighter. After the hot air rises, the cold air with low temperature flows in horizontally, and the rising air falls down because it gradually cools and becomes heavier. Because the surface temperature is high, it will heat the air and make it rise. This airflow is the wind.
When the gathered water vapor (cloud) forms water, its volume shrinks, and the surrounding water vapor comes to replenish it, forming wind. The wind on the earth is related to water sources. The expansion and contraction of water and steam produce wind. The wind blows from the ocean to the land, or the land blows to the ocean.
In summer, when the ground temperature is high, the air and water vapor expand and rise, so the air space on the ground should be supplemented with air and water vapor heavier than the sea surface. When the sea surface temperature is low and the air shrinks, the sea surface air space should be supplemented by the rising air and water vapor from the air with high ground temperature. In winter, when the sea surface temperature is high, the sea surface air rises, and when the ground temperature is low, the proportion of air is heavy, which supplements the sea surface space along the ground.