Impact of “blocking” structure in the troposphere on the wintertime persistent heavy air pollution in northern China

• DOI: 10.1016/j.scitotenv.2020.140325
• Publication Date: 2020-06-19T01:41:31Z
• Authors: Wenyue Cai; Xiangde Xu; Xinghong Cheng; Fengying Wei; Xinfa Qiu; Wenhui Zhu
• Keywords: Blocking (statistics)

In the winters of 2012–2018, a total 25 'ultra-long' (≥6 days), wide-ranging pollution events occurred in northern China. The results showed that atmospheric circulation pattern corresponding to 62.5% persistent 'most serious' and 'more air China were blocking structures, 43.75% 500-hPa anomalies middle high latitudes Eurasia 'dual-blocking', 18.75% them 'single-blocking'. abnormally stable situation provided special background for occurrence maintenance heavy Okhotsk is significantly positively correlated with events. 'Stagnation' system its dynamic effect play an important role regulating environmental capacity accelerating accumulation aerosols during episodes. Due synergy between weak wind leeward slope on eastern side Loess Plateau this region downward airflow large-scale system, sustained suppression pollutant diffusion more significant. flow along very pollutants, which controlled by tropospheric high. addition, 'subsidence (temperature) inversion' produced creates continuous 'warm-cover' structure troposphere Plateau; strengthens radiation as well 'two-way feedback' mechanism adverse meteorological conditions boundary layer pollutants.