What is the definition of ground cold high pressure?

Cold wave refers to a strong cooling weather process when a large range of cold air (cold high pressure in the air pressure field) invades China from the west or northwest of the Asian continent. In the weather forecast, it is defined as a cold wave weather process in which the temperature drops 10℃ within 24 hours and the lowest temperature in the process reaches below 5℃. The invasion of cold air in the north sometimes fails to meet this standard, but the temperature drop is also significant, so it is generally called strong cold air. In areas where cold waves or cold air fronts pass, there are often not only strong cooling, but also strong winds and precipitation (rain and snow). The formation of cold wave is due to the continuous accumulation and strengthening of cold air mass in Siberia in winter. When it becomes a strong cold high pressure, it will invade southward on a large scale under the guidance of the northwest airflow at the back of the high-altitude low pressure trough, thus forming a cold wave or a strong cooling weather process in the vast area north of Nanling in China. The cold wave invading China mainly has three paths: ① West Road: it enters Xinjiang from the west of Siberia and advances to the southeast through Hexi Corridor; ② Middle Road: After entering China from central Siberia and Mongolia, it passes through Hetao area and south-central China; (3) from eastern Siberia or eastern Mongolia into the northeast of China, south through North China.

Cold wave: the work is greater than the past.

The cold wave, that is, a large range of strong cold air heading south, like the tide, caused severe cooling and strong winds along the way.

The "passing" of the cold wave is the most impressive. It seems that when it comes to it, it will be associated with disastrous weather.

However, the benefits of the cold wave to human beings seem to be rarely mentioned. The research and analysis of geographers show that the cold wave contributes to the heat exchange on the earth's surface. With the increase of latitude, the energy received by the earth from solar radiation gradually weakened, so the earth formed tropical, temperate and cold zones. The cold wave injects a lot of cold air into tropical areas, which makes large-scale heat exchange on the ground, which is very helpful to maintain the ecological balance of nature and maintain the lush species.

Meteorologists believe that the cold wave is the guarantee of good weather. China is affected by monsoon, and the winter climate is dry, which is a dry season. However, whenever the cold wave invades the south, it will often bring a wide range of rain and snow weather, alleviate the winter drought and benefit crops. Why can the agricultural proverb "Xue Ruizhao has a good year" be circulated among the people for generations? This is because snow water has a high nitrogen content, which is more than five times that of ordinary water, and can greatly increase the nitrogen in the soil. Snow water can also accelerate the decomposition of soil organic matter, thus increasing the organic fertilizer in the soil. The heavy snow covered the overwintering crops and played the role of a quilt, keeping out the cold and keeping warm.

There is a saying that "winter is not cold, and the coming year is not abundant", which also has its scientific truth. Experts in crop pest control believe that the low temperature brought by the cold wave is the most effective natural "insecticide" at present, which can kill a large number of pests and germs lurking in the soil for the winter, or inhibit their reproduction and reduce pests and diseases in the coming year. According to the survey data of agricultural technology stations around the country, pesticides can be saved by more than 60% in the year of heavy snow and winter closure.

Cold waves can also bring wind resources. Scientists believe that wind is a valuable energy source without pollution.