20 10 reasons for the late snowfall in northern China.

Chen Dagang, chief of the Climate Analysis and Prediction Section of Beijing Meteorological Bureau, said with a smile when interviewed by this reporter that the most frequently asked sentence is "Why doesn't it snow in Beijing?"

Wang Xiao, reporter of Outlook Oriental Weekly

According to Weibo, "all winds that don't aim at snowing are hooligans", then from the winter of 20 10, Beijing has been "hooligans"-the lowest temperature dropped to MINUS 1 1.6 degrees Celsius, and flights were cancelled in windy weather, but it was not until 20165438.

While the low temperature rain and snow weather in the south continues to appear, the drought in North China is also attracting attention. According to media reports, the drought degree in Shandong, the second largest wheat producing area in China, has reached the standard of once in 60 years. 20 10 Since September 23, the cumulative average precipitation in Shandong Province has been 1 1mm, which is 86% less than that in the same period of normal years. There are 60.95 million mu of farmland in the province suffering from drought.

According to the observation data of Beijing Meteorological Observatory, there has been no effective precipitation in Beijing since 20 10/October 25th, and it has been 93 days.

"This year, Beijing is likely to break the record of the latest snowfall in 60 years." 65438+1On October 24th, Chen Dagang, chief of the climate analysis and prediction section of Beijing Meteorological Bureau, told Outlook Oriental Weekly.

Because 195 1 has a complete meteorological record, the latest time of the first snow in Beijing is 09841October 29th, 65438+65438. Judging from the data currently monitored by Beijing Meteorological Bureau, there is still no sign of snow in Beijing at least before 1 ends.

Abnormal atmospheric circulation causes no snow in Beijing.

"Why doesn't it snow in Beijing?" 20 1 1 at the beginning of the year, a netizen threw out such a question and wittily gave four options: a, I can't go without a Beijing hukou; B, the rent in Beijing is too expensive to afford; C. Don't dare to get off the bus in case of leadership travel and traffic control; D. I haven't paid enough taxes and endowment insurance for five years, and I can't shake the number.

This joke quickly became popular on the Internet.

Chen Dagang, chief of the Climate Analysis and Prediction Section of Beijing Meteorological Bureau, said with a smile when interviewed by this reporter that the most frequently asked sentence is "Why doesn't it snow in Beijing". His analysis is abnormal atmospheric circulation.

"The reason for the late snowfall is very simple from a meteorological point of view, that is, there is no warm and humid airflow. Snowfall should be accompanied by sufficient water vapor conditions, and the intersection of cold and warm air masses is the place with the most rain and snow. No one can control it unilaterally, and there will be no precipitation. After the winter of 20 10, the cold air quickly controlled the northern part of China, but the warm and humid airflow was delayed. Another condition that needs to be met is updraft, which can collect water vapor. If there is no such mechanism, even if there is precipitation, it may be a flash in the pan. "

Buhe Lu Chao, a researcher at lasg, believes that the deeper reason lies in the abnormal polar vortex activity and "La Nina phenomenon". "Under the influence of these two factors, since the winter, the high-pressure belt formed by the Ural Mountains and the North Pacific Ocean has transported cold air to the south very stably, resulting in the whole North China being under the control of the northwest airflow, and the warm and humid airflow in the south can't pass."

20 10 12.29, Snowflake hit a "edge ball" in the northwest of Beijing. Later, some netizens said that they saw something similar to "dandruff" floating near the North Fourth Ring Road. In the opinion of meteorologists, such snowfall belongs to boundless snowfall and cannot be called the first snow.

Chen Dagang explained that the conditions for the first snowfall in Beijing are that all five meteorological stations in Chaoyang, Haidian, Fengtai, Shijingshan and Nanjiao Observatory have observed snowfall, or more than three of these five stations have observed snowfall, and at least 1 station has detected snowfall greater than 0. 1 mm.

"It is possible that it will not snow all winter."

For people living in Beijing, winter without snow is obviously a little uncomfortable.

"In Beijing, it will definitely snow in winter. This is a fixed mode of thinking for everyone." Chen Dagang said that in fact, the average winter precipitation in Beijing only accounts for 2% of the whole year, which is a seasonal drought. "We usually talk about abnormal precipitation and temperature. In terms of precipitation, there is no rain or snow for more than three months, which can be called abnormal, but the temperature is not abnormal. Although everyone feels cold, in fact, the average temperature in June is only 65438+ 10, which is lower than normal, and the low range exceeds 1 Celsius. If we compare 65438+February, it is less than 1 degree Celsius lower than normal. But it is extremely low, generally referring to two or three degrees Celsius lower. "

Numerically, compared with the extremely cold climate in 2009, the temperature in Beijing this winter is moderate. On June 6th, 65438 10, the temperature in Beijing dropped to-16.7 degrees Celsius, breaking the record of the lowest extreme temperature of 65438+ 10 in early October in 38 years. This winter, as of 65438+1October 25th, the lowest temperature was only-1 1.6 degrees Celsius. Chen Dagang believes that this year's cooling is purely caused by cold air. "If it snows once or twice, the temperature will probably be lower than in the winter of 2009. The reason why people feel cold is because Beijing has been warm for more than ten years before 2009. "

According to statistics, during the same period 1970~ 197 1, there was no obvious precipitation in Beijing for consecutive days 1 16, and the precipitation in Beijing plain was only 0.6 mm, followed by 65438+20081October 24.

"It's possible that it won't snow all winter," Chen Dagang thought, but according to the situation of these decades, it will rain more or less.

Wen, former director of China Meteorological Bureau, told this reporter that if there is no snow in the future, there will only be sleet. "Now it seems that the record of the latest snowfall in the early 1960 s was immediately broken."