Possible influence of atmospheric circulations on winter haze pollution in the Beijing–Tianjin–Hebei region, northern China

Abstract

Abstract. Using the daily records derived from the synoptic weather stations and the NCEP/NCAR and ERA-Interim reanalysis data, the variability of the winter haze pollution (indicated by the mean visibility and number of hazy days) in the Beijing-Tianjin-Hebei (BTH) region during the period 1981 to 2015 and its relationship with the atmospheric circulations at middle-high latitude were analyzed in this study. The winter haze pollution in BTH had distinct inter-annual and inter-decadal variabilities without a significant long-term trend. According to the spatial distribution of correlation coefficients, six atmospheric circulation indices (I 1 to I 6 ) were defined from the key areas in sea level pressure (SLP), zonal and meridional winds at 850 hPa (U850, V850), geopotential height field at 500 hPa (H500), zonal wind at 200 hPa (U200), and air temperature at 200 hPa (T200), respectively. All of the six indices have significant and stable correlations with the winter visibility and number of hazy days in BTH. In the raw (unfiltered) correlations, the correlation coefficients between the six indices and the winter visibility (number of hazy days) varied from 0.57 (0.47) to 0.76 (0.6) with an average of 0.65 (0.54); in the high-frequency (< 10 years) correlations, the coefficients varied from 0.62 (0.58) to 0.8 (0.69) with an average of 0.69 (0.64). The six circulation indices together can explain 77.7 % (78.7 %) and 61.7 % (69.1 %) variances of the winter visibility and the number of hazy days in the year-to-year (inter-annual) variability, respectively. The increase in I c (a comprehensive index derived from the six individual circulation indices) can cause a shallowing of the East Asian trough at the middle troposphere and a weakening of the Siberian high-pressure field at sea level, and is then accompanied by a reduction (increase) of horizontal advection and vertical convection (relative humidity) in the lowest troposphere and a reduced boundary layer height in BTH and its neighboring areas, which are favorable for the formation of haze pollution in BTH winter, and vice versa. The high level of the prediction statistics and the reasonable mechanism suggested that the winter haze pollution in BTH can be forecasted or estimated credibly based on the optimized atmospheric circulation indices. Thus it is helpful for government decision-making departments to take action in advance in dealing with probably severe haze pollution in BTH indicated by the atmospheric circulation conditions.

East Asian Study of Tropospheric Aerosols and their Impact on Regional Clouds, Precipitation, and Climate (EAST‐AIRCPC)

“…Aerosol concentrations are also strongly modulated by monsoon circulation through surface winds, rain scavenging, and stratification stability (Chen & Wang, ; Jeong & Park, ; Jia et al, ; Liu, Sheng, et al, ; Zhang et al, ). In summer, haze‐fog events are related to the monsoon‐induced changes in air flow transport and moisture convergence over eastern China (Liu, Sheng, et al, ; Wu et al, ).…”

Numerical simulations of the effects of regional topography on haze pollution in Beijing

“…In particular, weather conditions play an essential role in controlling the daily variability of air pollutant concentrations 5,32–34 . Previous studies have suggested that there is a close relationship between the occurrence of winter haze pollution in the Beijing-Tianjin-Hebei region and atmospheric circulation at middle to high latitudes over a long-term perspective 35–37 . In addition, on interannual time scales, the air pollution across central and eastern China or even South Asia in the winter and summer is closely related to the East Asian winter and summer monsoons, respectively 38–45 .…”

The Effect of Meteorological Elements on Continuing Heavy Air Pollution: A Case Study in the Chengdu Area during the 2014 Spring Festival

“…In particular, meteorological conditions control the occurrence of haze pollution [3,[7][8][9][10][11][12][13][14][15][16][17][18][19]. In China, most studies are focused on the Jingjinji area (Beijing), the Yangtza river delta (Shanghai), and the Pearl River delta (Guangzhou, Zhujiang).…”