What data should be taken into account to anticipate the arrival of spring frost?

The importance of real-time data and their accuracy in anticpating the risk of spring frosts

From an agricultural point of view, the occurrence of a specific temperature cannot be considered as frost, as there are plants that suffer the consequences of low temperatures without it reaching zero degrees.

However, depending on the origin of the frost, it can be classified in different ways.

Advection frosts

In the first place, advection frosts are characterised by the arrival of a mass of cold air whose temperature is below 0ºC. Wind is an important parameter in this type of frost as it is not characterised by a thermal inversion (i.e. the temperature decreases as the altitude increases). It is usually above 15 km/h.

Radiation frosts

In contrast, radiation frosts are caused by a stratification of the air where the lower layers are colder and the higher layers are warmer (thermal inversion). This is due to the loss of terrestrial heat by irradiation during the night. This type of frost occurs in calm or low wind conditions, as the absence of wind prevents the mixing of these layers, and with clear skies that allow greater heat loss from the earth's surface. Heat loss is greater when nights become longer and the humidity of the air is lower. Areas of humidity accumulation and covered soils favour this type of frost. However, the roof can act as an insulator, preventing heat loss from the ground if it is controlled.

Evaporation frosts

Finally, there are evaporation frosts. These are caused by the loss of water by evaporation from the surface of the plant. This occurs when the relative humidity decreases and the dew evaporates. This transfer of energy to evaporate the water, requires heat which leads to cooling of the plant.

This type of frost can be classified into two categories based on visual effects;

• Fistly, white frost. This occurs when ice formation is observed on the plants. This type of frost occurs with humid air masses, calm wind and clear skies.
• And black frosts, where no ice forms. They are so called because of the colour that plant organs can have due to their destruction by the cold. This type of frost occurs when the air mass is dry. Overcast, semi-overcast skies or turbulence in the lower layers of the atmosphere favour the formation of this type of frost.

In concrete terms, how can I prevent spring frosts?

Monitoring each of the above parameters locally, at plot level, accurately and continuously is essential to protect crops equipped with some form of control system.

Monitoring the humidity temperature makes it possible to anticipate the minimum temperature that can be reached in the next few hours in order to act at the right time.

This is why Sencrop already integrates a frost sensor in its connected weather stations. Thanks to it, the farmer can observe the development of the temperature, dry and wet, in real time and thus create alerts so that he can be notified when the temperature falls below a defined threshold. This allows for early prevention and better organisation.

In addition, the historical maps allow a subsequent analysis of the affected areas according to the duration and intensity of the last frosts.

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