Atmospheric brown clouds: Hemispherical and regional variations in long-range transport, absorption, and radiative forcing

Abstract. Long-range transport of anthropogenic air pollutants from East Asia can affect the downwind marine air quality during spring and winter. Long-range transport of continental air pollutants and their interaction with sea salt aerosol (SSA) significantly modify the radiative forcing of marine aerosols and influence ocean biogeochemical cycling. Previous studies poorly characterize variations of aerosol particles along with air mass transport from the continental edge to the remote ocean. Here, the research ship R/V Dongfanghong 2 traveled from the eastern China seas (ECS) to the northwestern Pacific Ocean (NWPO) to understand what and how air pollutants were transported from the highly polluted continental air to clean marine air in spring. A transmission electron microscope (TEM) was used to find the long-range transported anthropogenic particles and the possible Cl-depletion phenomenon of SSA in marine air. Anthropogenic aerosols (e.g., sulfur (S)-rich, S-soot, S-metal/fly ash, organic matter (OM)-S, and OM coating particles) were identified and dramatically declined from 87 % to 8 % by number from the ECS to remote NWPO. For the SSA aging, 87 % of SSA particles in the ECS were identified as fully aged, while the proportion of fully aged SSA particles in the NWPO decreased to 29 %. Our results highlight that anthropogenic acidic gases in the troposphere (e.g., SO2, NOx, and volatile organic compounds) could be transported to remote marine air and exert a significant impact on aging of SSA particles in the NWPO. The study shows that anthropogenic particles and gases from East Asia significantly perturb different aerosol chemistry from coastal to remote marine air. More attention should be given to the modification of SSA particles in remote marine areas due to the influence of anthropogenic gaseous pollutants.

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Enhanced trans-Himalaya pollution transport to the Tibetan Plateau by cut-off low systems

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-3083-2017 ◽

2017 ◽

Vol 17 (4) ◽

pp. 3083-3095 ◽

Cited By ~ 18

Author(s):

Ruixiong Zhang ◽

Yuhang Wang ◽

Qiusheng He ◽

Laiguo Chen ◽

Yuzhong Zhang ◽

...

Keyword(s):

Tibetan Plateau ◽

Black Carbon ◽

Long Range ◽

Radiative Forcing ◽

Long Range Transport ◽

The Tibetan Plateau ◽

Pollution Transport ◽

Top Down ◽

Gangetic Plain ◽

Range Transport

Abstract. Long-range transport followed by deposition of black carbon on glaciers of Tibet is one of the key issues of climate research as it induces changes on radiative forcing and subsequently impacting the melting of glaciers. The transport mechanism, however, is not well understood. In this study, we use short-lived reactive aromatics as proxies to diagnose transport of pollutants to Tibet. In situ observations of short-lived reactive aromatics across the Tibetan Plateau are analyzed using a regional chemistry and transport model. The model performance using the current emission inventories over the region is poor due to problems in the inventories and model transport. Top-down emissions constrained by satellite observations of glyoxal are a factor of 2–6 higher than the a priori emissions over the industrialized Indo-Gangetic Plain. Using the top-down emissions, agreement between model simulations and surface observations of aromatics improves. We find enhancements of reactive aromatics over Tibet by a factor of 6 on average due to rapid transport from India and nearby regions during the presence of a high-altitude cut-off low system. Our results suggest that the cut-off low system is a major pathway for long-range transport of pollutants such as black carbon. The modeling analysis reveals that even the state-of-the-science high-resolution reanalysis cannot simulate this cut-off low system accurately, which probably explains in part the underestimation of black carbon deposition over Tibet in previous modeling studies. Another model deficiency of underestimating pollution transport from the south is due to the complexity of terrain, leading to enhanced transport. It is therefore challenging for coarse-resolution global climate models to properly represent the effects of long-range transport of pollutants on the Tibetan environment and the subsequent consequence for regional climate forcing.

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Simulation of Future Aerosol Distribution, Radiative Forcing, and Long-Range Transport in East Asia.

Journal of the Meteorological Society of Japan Ser II ◽

10.2151/jmsj.79.1139 ◽

2001 ◽

Vol 79 (6) ◽

pp. 1139-1155 ◽

Cited By ~ 23

Author(s):

Toshihiko Takemura ◽

Teruyuki Nakajima ◽

Toru Nozawa ◽

Kazuma Aoki

Keyword(s):

East Asia ◽

Long Range ◽

Radiative Forcing ◽

Long Range Transport ◽

Aerosol Distribution ◽

Range Transport

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Long-range transport of aerosols from East and Southeast Asia to northern Philippines and its direct radiative forcing effect

Atmospheric Environment ◽

10.1016/j.atmosenv.2019.117007 ◽

2019 ◽

Vol 218 ◽

pp. 117007 ◽

Cited By ~ 4

Author(s):

Gerry Bagtasa ◽

Mylene G. Cayetano ◽

Chung-Shin Yuan ◽

Osamu Uchino ◽

Tetsu Sakai ◽

...

Keyword(s):

Southeast Asia ◽

Long Range ◽

Radiative Forcing ◽

Long Range Transport ◽

Range Transport ◽

Direct Radiative Forcing ◽

East And Southeast Asia

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Enhanced Trans-Himalaya Pollution Transport to the Tibetan Plateau by the Cut-off Low System

10.5194/acp-2016-702 ◽

2016 ◽

Author(s):

Ruixiong Zhang ◽

Yuhang Wang ◽

Qiusheng He ◽

Laiguo Chen ◽

Yuzhong Zhang ◽

...

Keyword(s):

Tibetan Plateau ◽

Black Carbon ◽

Long Range ◽

Radiative Forcing ◽

Long Range Transport ◽

The Tibetan Plateau ◽

Pollution Transport ◽

Top Down ◽

Gangetic Plain ◽

Range Transport

Abstract. Long-range transport and subsequent deposition of black carbon on glaciers of Tibet is one of the key issues of climate research inducing changes on radiative forcing and subsequently impacting on the melting of glaciers. The transport mechanism, however, is not well understood. In this study, we use short-lived reactive aromatics as proxies to diagnose transport of pollutants to Tibet. In situ observations of short-lived reactive aromatics across the Tibetan Plateau are analyzed using a regional chemistry and transport model. The model performance using the current emission inventories over the region is poor due to problems in the inventories and model transport. Top-down emissions constrained by satellite observations of glyoxal (CHOCHO) are a factor of 2–6 higher than the a priori emissions over the industrialized Indo-Gangetic Plain. Using the top-down emissions, agreement between model simulations and surface observations of aromatics improves. We find enhancements of reactive aromatics over Tibet by a factor of 6 on average due to rapid transport from India and nearby regions during the presence of a high-altitude cut-off low system. Our results suggest that the cut-off low system is a major pathway for long-range transport of pollutants such as black carbon. The modeling analysis reveals that even the state-of-the-science high-resolution reanalysis cannot simulate this cut-off low system accurately, which probably explains in part the underestimation of black carbon deposition over Tibet in previous modeling studies. Furthermore, another model deficiency of underestimating pollution transport from the south is due to the complexity of terrain, leading to enhanced transport. It is therefore challenging for coarse-resolution global climate models to properly represent the effects of long-range transport of pollutants on the Tibetan environment and the subsequent consequence for regional climate forcing.

Download Full-text