How is the cold weather damage?

What is damaging cold malaria?

Bold cold is when the average daily temperature in the area ranges from 13 to 15 degrees Celsius.

Damage is when the average daily temperature in the area falls below 13 degrees C.

In the weather forecast news, it often refers to the cold, damaging cold phenomenon. This phenomenon is mainly understood for the Northern and midland regions and the North Central, where agricultural production is most active in the cold season. These terms do not apply to mountainous areas because there are cold, cold colds that do not occur in waves but occur almost every month. For example, in Sapa (Lao Cai), cold weather mostly occurs during December, January and February.

In fact, production in Vietnam with rice is the main food crop. The cold, damaging cold term is mainly used for agricultural production. Scientists have calculated that the average daily temperature below the cold, damaging threshold will affect the photosynthetic capacity of rice.

If the cold, damaging cold occurs in a day, the rice plant is still capable of photosynthesis and normal development. If it lasts for 2 days or more, the rice will no longer be able to photosynthesize and protect itself, leading to the possibility of resistance and death.

It is noted that the average daily temperature is below 15 degrees Celsius and 13 degrees Celsius must be associated with cloudy, cloudy weather conditions and may have small rain , when it is considered cold, damaging cold. In fact, on cloudy days at night, the temperature drops very low, but in the sunny day the temperature is very high, the average daily temperature can still be below 15 degrees Celsius but not considered cold.

How many types of cold air forecasts are available?

Depending on the specific situation of each cold air, with or without a cold front, the cold air forecasting message will be broadcast according to the following headings:

Believe the northeast monsoon is released when:

Cold air has the ability to penetrate into our country, fundamentally altering the existing wind system into the north wind, causing strong winds of level 6 or higher and lasting more than 3 hours above the North Bay. Ministry (and off the Central Coast);

Or when the cold air is able to penetrate into the North of our country, fundamentally changing the existing wind system from the front to the wind toward the north (not considering the wind speed), and also changing markedly weather in an area: cloudy, sudden increase in rainfall and average daily temperature of 3-5 degrees or more for more than half of stations in at least one area.

Or fundamentally alter the existing wind system from north to north wind (without considering wind speed), and cause heavy rain and thunderstorms in an area, there may be strong winds on the level. 6 or elements, whirlwinds, hail . and the maximum temperature drops by 5-7 degrees or more for more than half of the stations in at least one area.

Believe the northeast monsoon and cold: emitted like the northeast monsoon, but if you see a cold air wave, it is possible to reduce the average daily temperature in the northern delta and midland. less than 15 degrees (cold and damaging cold) and likely to last for 2 days or more.

Believe that cold air intensifies: This news is broadcast in the event that cold air intensifies to our country. While cold air exists in the northern provinces, the wind direction has not changed (still northward wind), but wind speed has been relatively weak, offshore wind has fallen below level 5, but the ability there is another round of cold air, causing strong winds of level 6 or higher and lasting more than 6 hours in the Gulf of Tonkin (and off the Central Coast).

News of cold air intensifies and colds : This news is distributed in the case of increased cold air but is capable of making the average daily temperature in the Northern Delta and midland areas fall below 150C and potentially lasts 2 days or more.