It is said that the climate will get hotter gradually, so why did the temperature in the south of China drop so low this winter, and was hit by a snowstorm?

Under the trend of global warming, why is it particularly cold this winter? Meteorologists explained that the frequent occurrence of extreme weather just shows that the trend of global warming remains unchanged.

"Generally speaking, the cold wave weather process takes one week as a cycle. The cold wave process that lasted for two weeks has not yet warmed up and will continue.

Gao Anning, chief forecaster of Guangxi Meteorological Observatory, said that global warming is a general trend and will increase meteorological extreme events. The extreme cold weather process that happened in the whole country is still a manifestation of global warming trend.

The National Climate Center predicts that the La Ni? a event, in which the sea surface temperature in the equatorial eastern Pacific dropped abnormally last year, will last until the summer of 2008, with moderate or strong intensity. In the winter when the La Ni? a event occurred, cold air activities were frequent.

According to experts, the intensity of cold air from Siberia and Mongolia this year is stronger than in previous years, and the scope of cold air activity is also larger than in previous years, which has a greater impact on the south of Henan and Anhui.

"Strong cold air constantly supplements the south and meets the warm and humid airflow in the southwest. It has been transiting over South China for a long time, and the rain and snow weather continued, which also caused the temperature to continue to drop. " Gao Anning said.

The second reason is that the two conditions that must be met when it snows or rains are 1. It comes from the warm and humid air flow in the tropics. There is cold air from high mountain area. The snowfall area in winter (the same as the rainfall area in summer) is distributed near the front, that is, the intersection of cold and warm air masses. This position is not fixed, but is determined by the strength of the two air masses. The cold air mass is weak, the front and precipitation areas have high latitudes, the cold air mass is strong, and the front and precipitation areas have low latitudes. The land cold high that affects China in winter is the Asian high centered on Mongolia and Siberia (also known as the Mongolian Siberian high), which has a very large sphere of influence and has a great impact on the weather in China, especially in the northern region. The cold air affecting our country in the early winter of this year is relatively weak, and the frequency is not much. Even with warm and humid airflow, it is not easy to snow without cold air. However, since 2008, the high pressure in Asia has been very active, and cold air masses have formed southward, affecting China and causing large-scale gale and cooling weather. However, due to the active warm air mass in the south this year, a large number of warm and humid air currents from the Pacific Ocean and the Indian Ocean frequently patronize the southern region. When the powerful cold air mass from Mongolia and Siberia quickly moved south to meet the warm and humid air mass, the cold and warm air just merged into one. Affected by these two air currents, there have been more rainy and snowy weather recently, especially in the Yangtze River basin, and the low temperature weather has lasted for a long time. If there is only a strong cold air mass without a large amount of water vapor provided by warm and humid air mass, there will only be strong winds and cool weather in the south; If there is only a large amount of water vapor provided by warm and humid air masses, there will be no disastrous weather at all without the arrival of cold air masses. And when both are ready, disaster comes ~