Influence of Intermittent Turbulence on Air Pollution and Its Dispersion in Winter 2016/2017 over Beijing, China

作者：Wei WEI,Hongsheng ZHANG,Xuhui CAI,Yu SONG,Yuxuan BIAN,Kaitao XIAO,He ZHANG

摘要：With rapid urbanization in recent years,severe air pollution has emerged as a major issue for many regions of China,especially in some metropolises.A persistent pollution case during 6 December 2016–8 January 2017 was selected to investigate the relations between turbulent intermittency and frequent PM2.5(particulate matters with diameter less than 2.5μm)pollution events over the metropolitan region of Beijing,China.The accumulation of PM2.5 near the surface frequently occurred as a combined result of strong inversion layers,stagnant winds,high ambient humidity levels,and stable stratification during this case.Arbitrary-order Hilbert spectral analysis indicated that steep decreases in the PM2.5 concentration were simultaneous with the occurrence of intermittent turbulence and strong vertical mixing.A wind profiler observation revealed existence of low-level jets(LLJs)at the end of the polluted periods,suggesting that the upper-level turbulent mixing accompanied by the wind shear of LLJ was transported downward and enhanced the vertical mixing near the surface,which might have caused an abrupt reduction in PM2.5 and improvement in air conditions.

发文机构：State Key Laboratory of Severe Weather Laboratory for Climate and Ocean–Atmosphere Studies State Key Joint Laboratory of Environmental Simulation and Pollution Control State Key Laboratory of NBC Protection for Civilian

关键词：INTERMITTENTTURBULENCEPM2.5stableSTRATIFICATIONBEIJING

分类号： X51[环境科学与工程—环境工程]X169