How do meteorology and agriculture classify cold dew wind?

Meteorology is the biggest factor affecting agriculture. In the long-term production practice, people have encountered all kinds of meteorological disasters. They try their best to predict and take preventive measures to reduce the losses it brings to agricultural production. Then I'll introduce you to a cold dew wind, which is a frequent meteorological disaster in southern China, and let you know how the grades of cold dew wind are divided.

What is cold dew wind?

Cold dew wind is actually a chilling injury caused by low temperature in autumn in southern China. Refers to the phenomenon that cold air invades in autumn, causing significant cooling, which in turn leads to the reduction of rice production. Because in southern China, this phenomenon mostly occurs before and after the solar terms of cold dew wind, so it is called cold dew wind.

Cold dew wind is one of the main meteorological disasters in the growth period of late rice in southern China. Every autumn, around the cold dew solar term, is the key period for heading and flowering of late rice in South China. At this time, if the low temperature is harmful, it will affect the normal heading and flowering of double-cropping late rice and late rice in South China, resulting in empty shells and shriveled grains, resulting in reduced production and great harm to crop production.

Classification of cold dew wind grade

According to the daily average temperature, the daily minimum temperature and the number of rainy days, the grades of cold dew wind are divided into dry cold type and wet cold type, and they are divided into mild and severe respectively. The daily average temperature, daily minimum temperature and rainy days corresponding to each grade are shown in the figure.

Classification of regional cold dew wind grades

The classification of regional cold dew wind can be divided into three grades: mild, moderate and severe according to the number and grade of stations where cold dew wind appears.

Regional mild cold dew wind

The number of stations with mild cold dew wind in this area has reached more than 35% of the total number of stations in this area.

Regional moderate cold dew wind

The number of mild or severe cold dew wind stations in the region reaches more than 50% of the total number of stations in the region, and the number of severe cold dew wind stations accounts for more than 10% of the total number of stations in the region.

Regional severe cold dew wind

The number of stations with severe cold dew wind in the region has reached more than 35% of the total number of regional stations; Or the number of stations reaching mild or severe cold dew wind reaches more than 60% of the total number of regional stations, and the number of stations reaching the standard of severe cold dew wind accounts for more than 20% of the total number of regional stations.