What is the standard of cold wave?

There are strict definitions and standards of cold wave in meteorology, but the standards of cold wave in different countries and regions are different. In 2006, it was stipulated in China that after a cold air invasion, the daily minimum temperature in a certain place decreased by ≥8℃ within 24 hours, or ≥ 10℃ within 48 hours, or ≥ 12℃ within 72 hours, and the daily minimum temperature in that place decreased below 4℃. The outbreak of cold wave has different characteristics in different geographical environments. In the northwest desert and loess plateau, it is characterized by less wind and snow, which is easy to cause sandstorm weather. On the grassland, it is windy and snowy, and the weather is cold. In North China and Huanghuai, cold waves are often accompanied by snow and snow. In the northeast, it is even more stormy, and in the south of the Yangtze River, it is often accompanied by biting rain.