The weather this year is generally colder than before. Is it once in a hundred years or is it related to global warming?

A rare snowstorm has continued since the founding of New China. In the context of global warming, why is there such a large range of snowfall and low temperature weather in China? Xinhua News Agency reporter Xinhua Viewpoint interviewed experts from China Meteorological Bureau. According to the latest data provided by the Forecast and Disaster Reduction Department of China Meteorological Bureau, the precipitation in nine provinces, including Sichuan, Shaanxi, Gansu, Qinghai, etc., has exceeded 20 years from January to 28th this year 1 month/kloc-0. Judging from the duration of snowfall, from 1 month128, the snowfall days in Jiangxi, Hunan and other provinces 1 1 are more than once in 20 years, among which Henan, Shaanxi, Gansu, Qinghai and Shanxi are more than once in 100, and Anhui Province. As of 1 27, the daily average temperature in Wuhan and Changsha has been close to or below zero degrees Celsius for nearly half a month. Historical records also provide a reference index for people to understand this low temperature weather. The temperature in Hubei, western Anhui, northwestern Jiangxi, Hunan, Guizhou and other places is 2-4 degrees Celsius lower than normal. The freezing rain and snow weather in Hunan and Hubei provinces has been the longest and most serious since 1954. The freezing rain and snow weather in Jiangxi province is the worst since meteorological observation data were available in 1959, and the duration of freezing rain and snow weather in 26 counties (cities) in Guizhou exceeds the historical record. According to Yang Guiming, chief forecaster of the Central Meteorological Observatory, compared with many years, the biggest feature of this year's blizzard is the short time interval between rain and snow. He said: "It is not uncommon for rain and snow to occur frequently in three or nine days, but this year 15 days has three processes, almost once a week, and each time it is a long-lasting large-scale snowfall, which is rare in history." The abnormal atmospheric circulation under La Nina phenomenon is the "culprit" of snowstorm. "The direct cause of the recent large-scale rain and snow weather is the abnormal atmospheric circulation." Sun Jun, chief forecaster of the Central Meteorological Observatory, said. He analyzed that from the evolution of atmospheric circulation in the short and medium term, there have been frequent cold air and active warm and humid airflow since the winter of this year. Especially since 1 month, the circulation in the middle and high latitudes is mainly meridional, with frequent cold air activities. In addition, the subtropical system is strong, northwest than normal, which is conducive to transporting warm and humid air from the south to the north. On the one hand, the cold air in the north is very active, and the warm and humid airflow in the south is constantly transported northward. The intersection of cold and warm air currents is mainly located in the central and eastern regions of China, which creates favorable circulation conditions for large-scale rain and snow weather. This year's atmospheric circulation anomaly is related to the "La Nina event" that is taking place in the equatorial Middle East Pacific. Li Weijing, deputy director of the National Climate Center, said that from the perspective of climate change, the current low temperature in the equatorial Middle East Pacific is one of the manifestations of the "La Nina" phenomenon. Statistical analysis shows that the meridional dimension of mid-latitude atmospheric circulation may be strengthened in the winter of the year and the spring of the following year when the strong La Nina event occurred, that is, frequent cold air activities may easily lead to low temperature in most parts of northern and eastern China and more precipitation in the north of the Yangtze River. Why is this year's heavy snow so slow to "recede"? Experts attribute the reason to the stability of atmospheric circulation. Sun Jun said: "It is precisely because of the stable atmospheric circulation during this period that the warm and humid airflow and cold air in the southwest have been around 30 degrees north latitude, especially in the middle and lower reaches of the Yangtze River, so there will be no obvious turning point in the recent rain and snow weather." Yang Guiming introduced that there are several kinds of cold air affecting China: First, the cold air mass comes from polar directions, such as Mongolia and Lake Baikal, and the cold air force is strong, mainly due to strong winds and cooling processes. Second, the cold air mass from Siberia will also bring strong winds and cool weather, but the intensity is not as good as the former. There is also a kind of cold air coming from the west road, such as starting from Iceland, passing through the European Mediterranean and coming from west to east. This kind of cold air is easy to bring a wide range of snowfall. "The continuous snowfall in China this year is because the southwest warm and humid airflow from the west road meets the cold air east of Lake Baikal on the east road in Huanghuai, Jianghuai and northern Jiangnan. In addition, the warm and humid airflow in Huanghuai is more active, and it is prone to snowstorm weather. " Yang Guiming said. In the face of extreme weather events, what should we do if we switch to northern China? This large-scale snowfall is not unusual in terms of snowfall or duration, but it has caused disasters that have never happened in decades or even centuries in some areas in the south. Experts believe that the main reason is that the cold protection mechanism in the vast areas of the south is relatively weak. Li Weijing suggested that in the context of global warming, in addition to strengthening the establishment of a cold-proof mechanism in the southern region and actively taking disaster prevention measures, it is also necessary to raise public awareness of extreme weather and climate events such as blizzard and take active and effective countermeasures as soon as possible. He believes that in response to extreme weather, the meteorological department has the responsibility to do a good job in monitoring and analysis, forecasting and early warning and disaster impact assessment of low-temperature rain, snow and freezing weather. Experts remind the public that in the season prone to blizzard weather, they should pay close attention to the weather forecast, strengthen traffic safety, and clear the road ice and snow in time; Strengthen the deicing, snow removal and anti-freezing work of water, electricity, gas and communication facilities; Strengthen agricultural infrastructure such as farmhouses and vegetable greenhouses, and tighten outdoor structures; Strengthen the cold and warm work of outdoor workers and farmers.