Climate modulation of the Tibetan Plateau on haze in China

Abstract

Abstract. Rapid increases in pollutant emissions in conjunction with stagnant meteorological conditions result in haze pollution in China. Recent frequent haze in China has attracted worldwide attention. Here we show a relationship between the haze events and Tibetan Plateau (TP)'s environment and climate changes. Based on observational data taken over recent decades, we identify central-eastern China (CEC) as a climatological large-scale "susceptible region" of frequent haze, which is harbored by the TP with its impact on midlatitude westerly winds. The observational and modeling studies demonstrate that the interannual variations in the thermal forcing of TP are positively correlated with the incidences of wintertime haze over CEC. Further analysis indicates that the climate warming of the TP induced changes in atmospheric circulation, driving frequent haze events in CEC. The frequent haze occurrences in CEC are consistent with decreasing winter monsoon winds, intensifying downward air flows and increasing atmospheric stability in the lower troposphere over the CEC in association with upstream plateau's thermal anomalies. Therefore, variations of haze in China are related to mechanical and thermal forcing by the TP. Our results also suggest that implications of the large TP topography for environment and climate changes should be taken into account for air pollution mitigation policies in China.

Quantifying the relationship between PM<sub>2.5</sub> concentration, visibility and planetary boundary layer height for long-lasting haze and fog–haze mixed events in Beijing

“…The maximum RH of each fog-haze mixed event was larger than 90 %. The results were consistent with the studies of Xu et al (2016) and Q. , in which the observed RH less than 90 % was used to separate haze events from fog events under the visibility < 10 000 m due to the difficulty of measuring RH correctly.…”

“…In addition, the interactions between aerosol pollution and climate change have been substantially addressed in recent publications, for example anthropogenic climate change (Cai et al, 2017), reduced Arctic sea ice Zou et al, 2017), the Tibetan Plateau warming (Xu et al, 2016), influences of ENSO events on haze frequency in eastern China , weakened East Asian winter monsoon , decadal weakening of winds and enhanced thermal stability of the lower atmosphere Chen and Wang, 2015). Dustwind interaction (Yang et al, 2017a) and upwind transport (Yang et al, 2017b) could also intensify haze events in China.…”

Air quality in the middle and lower reaches of the Yangtze River channel: a cruise campaign

“…The MLYR region faces the most complex anthropogenic emission sources, including a variety of power plants, large petrochemical and steel industries, and farmland distributed along both banks of the Yangtze River, as well as ship emissions. It was well documented that ship emissions displayed a significant impact on regional air quality, particularly in traffic hubs and harbors (Pandis et al, 1999;Becagli et al, 2017;Zhan et al, 2014). The contribution and effect of ship emissions to local air pollution, especially PM, have been briefly analyzed at regional to global levels (Jalkanen et al, 2016;Zhan et al, 2014;Pandis et al, 1999;Fan et al, 2016;Coggon et al, 2012).…”

“…It was well documented that ship emissions displayed a significant impact on regional air quality, particularly in traffic hubs and harbors (Pandis et al, 1999;Becagli et al, 2017;Zhan et al, 2014). The contribution and effect of ship emissions to local air pollution, especially PM, have been briefly analyzed at regional to global levels (Jalkanen et al, 2016;Zhan et al, 2014;Pandis et al, 1999;Fan et al, 2016;Coggon et al, 2012). The emission factors, and properties of emitted particles and gases from ship plumes at different engine speeds, were also reported Moldanová et al, 2009;Agrawal et al, 2009).…”

Self-organized classification of boundary layer meteorology and associated characteristics of air quality in Beijing

“…1). Under favorable weather conditions (e.g., stagnant weather), terrain-related circulations can be well developed over Beijing and its surroundings, leading to a complex ABL structure, which is thought to substantially affect Beijing's air quality Miao et al, 2017;Ye et al, 2016;Gao et al, 2016;Xu et al, 2016). With high emissions of air pollutants from anthropogenic sources, Beijing is suffering serious air pollution problems and the pollution can be even more severe when southwesterly and southeasterly winds prevail within the ABL (Chen et al, 2008;Ye et al, 2016;Zhang et al, 2014Zhang et al, , 2012.…”