Why is the North cold abnormally?

The impact of La Nina is the cause of climate abnormalities in many parts of the world, in which northern Vietnam faces a colder winter than usual.

Ms. Dao Thi Thuy, School of Climate Forecasting, Institute of Hydrometeorology, explains part of the cause of the current deep and prolonged cold spell.

Madam, does the North have an unusual cold wave because of?

Last year there was an unusual double phenomenon between El Nino and La Nina . It was the beginning of the year with El Nino, La Nina appeared last year. La Nina's expression is becoming more and more obvious, causing abnormal cold phenomenon.

Snow ice appears on Sa Pa

La Nina is a cold phase in the Enso phenomenon (a double phenomenon, showing a periodic fluctuation of the ocean atmosphere), including two atmospheric phenomena, El Nino, with sea surface temperatures rising more than the average. year and La Nina with sea surface temperature decreased more than the average for many years.

La Nina has the effect of reducing temperature in the eastern and central Pacific. Vietnam is in the northwest Pacific, but is also affected. Therefore, this cold spell is due to the impact of La Nina on the climate of Vietnam. La Nina has an impact on the major months of winter - December, January and February, pulling the temperature down to lower than normal.

Besides, Vietnam is cold due to the post-humidity climate. While the countries are cold and dry, so it doesn't cut off the skin like in Vietnam. In the country we only need a temperature of less than 3 degrees to have snow; In other countries, it must be cold or 4 degrees. So in countries like Europe, they still don't feel as cold as in Vietnam.

According to scientists around the world, maybe 2011 is an unusually cold year. This cold is an anomaly of the climate all over the world, not just Vietnam.

Other normal years still have the phenomenon of El Nino and La Nina interwoven, so why not feel cold like now?

Yes, In previous years, there were El Nino and La Nina phenomena in succession, which could last longer. In 2010, both of these phenomena took place in a year.

Normally, in the cycles of El Nino and La Nina, when either of these phenomena ends, it is followed by an intermediate year (ie a year of normal climate). Each cycle lasts about 2-7 years. For example, after El Nino in 2007, the winter of the following year was very cold due to the influence of La Nina.

Many people still think that, when it comes to El Nino is hot, La Nina is cold. What do you think?

This is true only for Vietnam. Ie El Nino is associated with hot weather, while La Nina is associated with cold weather. In other countries, it is not so, because the impact of the weather phenomenon is different in different regions.

How long can the impact of La Nina phenomenon on Vietnam last?

The coldest weather only falls in January 2011. Scientists predict that La Nina phenomenon lasts until the end of spring this year. If the impact is late, prolonged, summer may be relatively cool. This year's Lunar New Year, I affirmed that it cannot be hot, can only be warmer than the present, even spring rains may appear, causing cold feeling.

Unable to conclude, winter 2011 is the period with the coldest winter in history or not . Because knowing somewhere, there will still be a time when the temperature is lower than the current. So far the coldest time recorded in Vietnam is 1974 (minus 6 degrees Celsius).