Is water vapor a key player of the wintertime haze in North China Plain?

Wu, Jiarui; Bei, Naifang; Hu, Bo; Liu, Suixin; Zhou, Meng; Wang, Qiyuan; Li, Xia; Liü, Lang; Feng, Tian; Liu, Zirui; Wang, Yichen; Cao, Junji; Tie, Xuexi; Wang, Jun; Molina, Luisa T.; Li, Guohui

doi:10.5194/acp-19-8721-2019

Cited by 53 publications

(28 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The anomalous southerly flows give rise to the accumulation of pollutants and moisture over Beijing, with reduced surface wind speeds, which is conducive to the accumulation of air pollutants (Wu et al 2017). Abundant moisture over the Beijing region enhances aerosol scattering and secondary aerosol formation, resulting in the accumulation of pollutants (Wu et al 2019. Figure S2 depicts correlation coefficients between anomalous variables of atmospheric circulation from the near-surface to the upper troposphere and the intensity of haze days in Beijing in winter from 1980 to 2017.…”

Section: Both Anthropogenic Emissions and Climatic Conditions Determimentioning

confidence: 99%

Climate variability or anthropogenic emissions: which caused Beijing Haze?

Pei

Zeng

Chen

et al. 2020

Environ. Res. Lett.

View full text Add to dashboard Cite

Beijing Haze has been phenomenal, especially for winter, and widely considered a result of the increasing anthropogenic emissions of atmospheric pollutants in the region. Since 2013, the pollutant emissions have been reduced with the help of a series of emission-control actions. However, severe haze events still occurred frequently in Beijing in recent winters, e.g., those of 2015 and 2016, implying that other factors such as meteorological conditions and interannual climate variability have also played an important role in forming the haze. Based on homogenized station observations, atmospheric circulation reanalysis and anthropogenic emissions data for the period 1980-2017, this paper attempts to quantify the relative importance of anthropogenic emissions and climatic conditions to the frequency and intensity of Beijing Haze in winter. It is found that the frequency (number) of hazy days exhibits large interannual variability and little trend, and its variations were mainly controlled by climate variability, with a correlation coefficient of 0.77. On the other hand, the intensity of haze displays strong interannual variability and a significant increasing trend during 1980-2012 and a notable decreasing trend during 2012-2017. The multiple linear regression model suggests that about half of the total variance of the haze intensity is explained by climate variability (mainly for interannual variations), and another half by the changing emissions (mainly for the trends).

show abstract

Section: Both Anthropogenic Emissions and Climatic Conditions Determimentioning

confidence: 99%

Climate variability or anthropogenic emissions: which caused Beijing Haze?

Pei

Zeng

Chen

et al. 2020

Environ. Res. Lett.

View full text Add to dashboard Cite

show abstract

“…Huang et al (2019) further found that concurrent changes in the location of the subtropical and polar front jet in East Asia in winter has an important impact on the climate of East Asia. In addition, previous studies showed that the North Atlantic was a source of teleconnection waves, where anomalies in atmospheric circulation related to sea surface temperatures (SSTs) can significantly influence winter weather in the Northern Hemisphere (Wallace and Gutzler, 1981;Peng et al, 1995;Czaja and Frankignoul, 2002;Li and Bates, 2007) and can influence haze in China (Xiao et al, 2014;Gao and Chen, 2017). Chen et al (2013) noted that cold air outbreaks were possibly associated with the development of the Siberian high pressure and a wave train from the North Atlantic.…”

mentioning

confidence: 99%

The combined effect of two westerly jet waveguides on heavy haze in the North China Plain in November and December 2015

Liu

et al. 2020

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Severe haze occurred in the North China Plain (NCP) from November to December 2015, with a wide spatial range and long duration. In this paper, the combined effect of the anomalous stationary Rossby waves within two westerly jet waveguides on this haze event in the NCP is investigated based on observational visibility data and NCEP/NCAR reanalysis data. The results show that circulation anomalies in Eurasia caused by the propagation of anomalous stationary Rossby wave energy along two waveguides within the westerly jet originating from the Mediterranean were responsible for haze formation in the NCP. The Rossby waves propagated eastward along the subtropical westerly jet and the polar front jet, causing an anomalous anticyclone over the Sea of Japan and anticyclonic wind shear at 850 hPa over the NCP, which enhanced the anomalous descent in the middle and lower troposphere and subsequently resulted in a stable lower atmosphere. Furthermore, the anomalous stationary Rossby waves propagating along the polar front jet weakened the East Asia trough and Ural ridge and strengthened the anomalous southerly wind at 850 hPa over the coastal areas of eastern China, decelerating the East Asia winter monsoon. The above meteorological conditions modulated haze accumulation in November and December 2015. Meanwhile, continuous rainfall related to ascending motion due to Rossby wave propagation along the waveguide provided by the subtropical westerly jet occurred in a large area of southern China. The associated latent heat release acted as a heat source, intensifying the ascending motion over southern China so that the descending motion over the NCP was strengthened, favoring the maintenance of severe haze. This study elucidates the formation and maintenance mechanism of large-scale haze in the NCP in late fall and boreal winter.

show abstract

“…On the other hand, the average RH reached as high as 91.7%, which was approximately 1.3 times higher than the first period. Increasing RH facilitates the aerosol hygroscopic growth and further enhances the aerosol liquid water, facilitating the secondary aerosols formation by serving as an important medium for liquid-phase and heterogeneous reactions [26]. Therefore, high RH will increase PM 2.5 concentrations and worsen pollution.…”

Section: Summary Of a Haze Episodementioning

confidence: 99%

“…High RH played an important role in the formation of PM 2.5 . However, when RH > 80%, PM 2.5 concentrations began to decrease due to the high frequency of precipitation [25,26].…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Aerosols and Chemical Composition Apportionment under Different Pollution Levels in Wuhan during January 2018

et al. 2019

View full text Add to dashboard Cite

To clarify the aerosol optical properties under different pollution levels and their impacting factors, hourly organic carbon (OC), elemental carbon (EC), and water-soluble ion (WSI) concentrations in PM2.5 were observed by using monitoring for aerosols and gases (MARGA) and a semicontinuous OC/EC analyzer (Model RT-4) in Wuhan from 9 to 26 January 2018. The aerosol extinction coefficient (bext) was reconstructed using the original Interagency Monitoring of Protected Visual Environment (IMPROVE) formula with a modification to include sea salt aerosols. A good correlation was obtained between the reconstructed bext and measured bext converted from visibility. bext presented a unimodal distribution on polluted days (PM2.5 mass concentrations > 75 μg⋅m−3), peaking at 19:00. bext on clean days (PM2.5 mass concentrations < 75 μg⋅m−3) did not change much during the day, while on polluted days, it increased rapidly starting at 12:00 due to the decrease of wind speed and increase of relative humidity (RH). PM2.5 mass concentrations, the aerosol scattering coefficient (bscat), and the aerosol extinction coefficient increased with pollution levels. The value of bext was 854.72 Mm−1 on bad days, which was 4.86, 3.1, 2.29, and 1.28 times of that obtained on excellent, good, acceptable, and poor days, respectively. When RH < 95%, bext exhibited an increasing trend with RH under all pollution levels, and the higher the pollution level, the bigger the growth rate was. However, when RH > 95%, bext on acceptable, poor and bad days decreased, while bext on excellent and good days still increased. The overall bext in Wuhan in January was mainly contributed by NH4NO3 (25.2%) and organic matter (20.1%). The contributions of NH4NO3 and (NH4)2SO4 to bext increased significantly with pollution levels. On bad days, NH4NO3 and (NH4)2SO4 contributed the most to bext, accounting for 38.2% and 27.0%, respectively.

show abstract

Is water vapor a key player of the wintertime haze in North China Plain?

Cited by 53 publications

References 76 publications

Climate variability or anthropogenic emissions: which caused Beijing Haze?

Climate variability or anthropogenic emissions: which caused Beijing Haze?

The combined effect of two westerly jet waveguides on heavy haze in the North China Plain in November and December 2015

Optical Properties of Aerosols and Chemical Composition Apportionment under Different Pollution Levels in Wuhan during January 2018

Contact Info

Product

Resources

About