From 3 1, the weather conditions will tend to be calm and steady, and the foggy weather in North China and other places will rise again. 65438+1On October 3, a weak cold air will make North China and other places "catch their breath" from the smog, but from April 4 to 6, the smog weather in the above areas will develop again.
Zhou Bing, chief expert and research-level senior engineer of the Climate Monitoring Office of the National Climate Center, said that this year's smog mostly occurred in the climate background of El Ni? o, which started to develop in May last year and has been maintained continuously. It has obviously strengthened since this summer, and now it has become a super El Nino event, with the peak value close to 1997 to 1998, ranking second since 1950.
Although the sustained development of El Ni? o has no direct impact on the frequent smog weather in Beijing, Tianjin and Hebei, it can affect the subtropical high system and the intensity of East Asian winter monsoon, and affect the atmospheric circulation system in the middle and high latitudes, so that the cold air activity is reduced and the intensity is weakened.
Ma Xuekuan, chief forecaster of Environmental Meteorological Center of China Meteorological Bureau, also said that meteorological factors are the key factors leading to frequent haze weather in Beijing, Tianjin and Hebei.
Since the beginning of winter, Beijing-Tianjin-Hebei region has experienced four severe haze weather processes, of which the process from February 65438+ to 25 19 to 25 has the widest influence and the longest duration.
Ma Xuekuan analyzed that the frequent smog weather in Beijing, Tianjin and Hebei is related to both the intensity and distribution of pollutant emission sources and unfavorable meteorological conditions. Meteorological reasons include: First, the intensity of cold air is weak, there are more windy days, and the horizontal diffusion ability of pollutants is poor. Secondly, the atmospheric stratification is stable and the top height of the mixed layer is low, which inhibits the vertical diffusion of pollutants. Coupled with the high air humidity, the hygroscopicity of pollutants increased, and the chemical reaction became more obvious, resulting in a sudden increase in PM2.5
Ma Xuekuan said that smog weather is frequent, pollution discharge is the internal cause, and meteorological conditions are the external cause and the key factor.