Winter monsoon variability and its impact on aerosol concentrations in East Asia

Jeong, Jae-In; Park, Rokjin J.

doi:10.1016/j.envpol.2016.11.075

Cited by 96 publications

(57 citation statements)

References 54 publications

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“…Some studies have connected long-term variation in the frequency of cold surges with aerosol concentrations in North China. On interannual time scales, the occurrence of cold surges has a negative correlation with the number of haze-fog days in eastern China (Jeong & Park, 2017;Li et al, 2016;Liu et al, 2017;Tao et al, 2016). The decreasing frequency of cold surges in recent years may have contributed to decreased visibility and increased fog (Niu et al, 2010;Qu et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Impacts of Cold Airmass on Aerosol Concentrations Over North China Using Isentropic Analysis

2019

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Winter air quality can vary markedly due to cold air activities. However, the impacts of the polar cold airmass on aerosol variations has not been clarified in a quantitative manner. Using an isentropic analysis method, we investigated changes in the cold airmass and sulfate aerosol distributions over North China during the winter of 2014/2015. The cold airmass and sulfate concentrations exhibited pronounced out‐of‐phase variations, with comparable amplitudes at subseasonal (30–60 days) and synoptic (4–6 days) scales. Subseasonal sulfate variations were closely associated with distribution of the polar cold airmass, as it shifted between zonal and meridional patterns, regulating cold airmass fluxes over North China. Typically, subseasonal surges in the cold airmass consisted of several synoptic disturbances, including one cold air outbreak event and 3–6 renewal/decay oscillations. These synoptic inflows of clean cold airmass repeatedly pushed the warm polluted airmass away from North China. Thus, spatiotemporal variations in sulfate better reflect cold airmass distributions and fluxes than northerly wind regimes. Using diagnostic equations derived herein, we estimated the contribution of various physical processes to aerosol variations during cold air anomalies. We found that the local changes in sulfate concentrations were mainly attributed to advection of warm airmasses, as well as advection and vertical displacement by horizontal convergence of the polar cold airmass. The latter two processes contributed most to sulfate decreases, leading to a relatively strong aerosol reductions during cold air outbreaks, while first two processes led to weaker aerosol reductions during cold air oscillations.

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Section: Introductionmentioning

confidence: 99%

Quantifying the Impacts of Cold Airmass on Aerosol Concentrations Over North China Using Isentropic Analysis

2019

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“…EANET (2014), AD-Net Lidar (Sugimoto et al, 2008), and other monitoring data have been accumulating observation data for more than 10 years, but most of these data do not include detailed hourly aerosol compositions. Seasonal changes in Asian monsoons play an important role in the pattern and frequency of long-range transport of pollutants (e.g., Jeong and Park, 2017); therefore, long-term aerosol observation including aerosol compositions with high resolution is required, but such a detailed observation has not yet been well-performed.…”

Section: Introductionmentioning

confidence: 99%

Importance of Long-Range Nitrate Transport Based on Long-Term Observation and Modeling of Dust and Pollutants over East Asia

Uno

Osada

Yumimoto

et al. 2017

Aerosol Air Qual. Res.

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Long-term synergetic fine and coarse mode aerosol observations were analyzed at 1-h intervals at Fukuoka, Japan, from January to June 2015. The GEOS-Chem chemical transport model, including dust and sea-salt acid uptake processes, was used for detailed analysis of observation data. Several Asian dust events and long-range anthropogenic aerosol transport events were observed during our analysis period, and the numerical model generally explained the observed time variation for both fine and coarse mode aerosols. We found that (i) the majority of fine mode NO 3 -can be considered as long-range transport (LRT) outside of Japan during the cold season, and (ii) the peak timing of fine mode NO 3 -coincided with that of SO 4 -, indicating that both aerosols are controlled by LRT. Also, an observed mass concentration ratio of NO 3 -/SO 4 2-> 0.9 occurred during the cold season, indicating the importance of NO 3 -as a major contributor to the PM 2.5 mass fraction. Finally, we clearly showed that large-scale dust-nitrate outflow from China to Fukuoka was confirmed in all cases of dust events, indicating that the anthropogenic NO x is converted to dust-nitrate and transported to Japan with dust. These results demonstrate the importance of anthropogenic NO 3 -LRT during the cold season and dust-nitrate LRT for all dust events (even in June).

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“…For example, Jiang et al . [] suggested that anthropogenic aerosols cool surface air temperatures by up to 1.2 K over eastern and central China, while heating the Tibetan Plateau by up to 1.8 K. While the anthropogenic aerosols are found to increase by up to 25% over southern China but decrease in the rest of China between the strongest and weakest EAWM years (strongest minus weakest [ Jeong and Park , ]), it indicates that the interannual variations of anthropogenic aerosol strengthen the aerosol‐induced cooling effect in southern China while weakening the cooling effect in other regions. Our results illustrate that the interannual variations in natural aerosols might offset the strength of the cooling effect over the southern part of coastal China (south of 30°N) that results from interannual variations of anthropogenic aerosols, while also weakening the cooling effect over the northern part of coastal China (north of 30°N).…”

Section: Resultsmentioning

confidence: 99%

Impacts of interactive dust and its direct radiative forcing on interannual variations of temperature and precipitation in winter over East Asia

et al. 2017

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We used two 150 year preindustrial simulations of the Community Earth System Model, one with interactive dust and the other with prescribed dust, to quantify the impacts of changes in wind during East Asian winter monsoon (EAWM) season on dust emissions, and the resulting consequences for interannual variations of temperature and precipitation over East Asia. The simulated December‐January‐February dust column burden and dust optical depth are lower over northern China in the strongest EAWM years than those of the weakest years by 38.3% and 37.2%, respectively. The decrease in dust over the dust source regions and the downwind region leads to an increase in direct radiative forcing (RF) at the surface by up to 1.5 W m−2. The effects of EAWM‐related variations in surface winds, precipitation, and their effects on dust emissions and wet removal contribute 67% to the total dust‐induced variations of direct RF at the surface and partly offset the cooling that occurs with the EAWM strengthening by heating the surface. The variations of surface air temperature induced by the changes in wind and dust emissions between the strongest and weakest EAWM years (strongest minus weakest) decrease by 0.4–0.6 K from eastern coastal China to Japan, which weakens the impact of EAWM on surface air temperature by 3–18% in these regions. The warming results from the combined effects of changes in direct RF, turbulent heat flux at the surface, and northwesterly wind anomalies that bring cold and dry air from Siberia to these regions. Over eastern coastal China, the variations of large‐scale precipitation induced by the feedback of EAWM‐related changes in wind on dust emissions decrease by 10–30% in winter because of the reduced changes in surface air temperature and the anomalous circulation.

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Winter monsoon variability and its impact on aerosol concentrations in East Asia

Cited by 96 publications

References 54 publications

Quantifying the Impacts of Cold Airmass on Aerosol Concentrations Over North China Using Isentropic Analysis

Quantifying the Impacts of Cold Airmass on Aerosol Concentrations Over North China Using Isentropic Analysis

Importance of Long-Range Nitrate Transport Based on Long-Term Observation and Modeling of Dust and Pollutants over East Asia

Impacts of interactive dust and its direct radiative forcing on interannual variations of temperature and precipitation in winter over East Asia

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