Indirect forcing of black carbon on clouds over northeast India

Panicker, A. S.; Pandithurai, G.; Safai, P.D.; Prabha, Thara V.

doi:10.1002/qj.2878

Cited by 7 publications

(5 citation statements)

References 36 publications

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“…This means both enhanced CCN ability and high number concentration of BC under high pollution may contribute to the significantly increased BC contained in cloud particles. The absorption of BC incorporated into clouds will be further amplified by the lensing effect by being encapsulated in water droplets, and the strong absorption inside droplets may play important roles in evaporating clouds , or decreasing the cloud albedo. , There will be much less BC in clouds under a cleaner environment over the Beijing region, also over continental Europe. Considering the efficient mixing in the PBL, the characteristics of BC measured on the surface may represent those at the top of the PBL where the particles started to form clouds, whereas the BC in the upper level, which may be entrained into clouds at different stages of cloud development.…”

Section: Resultsmentioning

confidence: 99%

Size-Related Physical Properties of Black Carbon in the Lower Atmosphere over Beijing and Europe

Ding

Zhao

Kang

et al. 2019

Environ. Sci. Technol.

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The size-resolved properties of atmospheric black carbon (BC) importantly determine its absorption capacity and cloud condensation nuclei (CCN) ability. This study reports comprehensive vertical profiles of BC size-related properties over the Beijing area (BJ) and Continental Europe (CE). BC mass loadings over CE were in the range of clean background over BJ. For both planetary boundary layer (PBL) and lower free troposphere, the BC mass median core diameter over BJ during the cold season was 0.21 ± 0.02 μm, larger than the warm season over BJ and CE (0.18 ± 0.01 μm), which may reflect seasonal differences in emissions. The BC coatings were positively correlated with the pollution level, with background BC having a smaller coated count median diameter (0.19 ± 0.01 μm). The modeled absorption enhancement (E abs) due to coatings was 1.23 ± 0.14 for the background but in the PBL following a linear expression (E abs = 0.13 × MassBC,surface + 1.26). The CCN ability of BC was significantly enhanced in the polluted PBL, due to both enlarged size and increased hygroscopicity. In polluted BJ at predicted supersaturations, ∼0.08% half of the BC number could be activated, whereas the cleaner environment needs ∼0.14%. The results here suggest that the highly coated and absorbing BC can be efficiently incorporated into clouds and can exert important indirect radiative impacts over the polluted East Asia region.

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Section: Resultsmentioning

confidence: 99%

Size-Related Physical Properties of Black Carbon in the Lower Atmosphere over Beijing and Europe

Ding

Zhao

Kang

et al. 2019

Environ. Sci. Technol.

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“…However, positive BC indirect radiative effects were also found especially over remote oceanic and coastal regions because of the reduced aerosol hygroscopicity over these regions (Kristjánsson, 2002;Bond et al, 2013). BC indirect effects were also found to be responsible for the reduction of the cloud reflection over the North East Indian region in a recent study by Panicker et al (2016). The purpose of this study is to assess the indirect radiative effects of BC aerosols, and their implications for climate.…”

Section: Introductionmentioning

confidence: 99%

Black carbon indirect radiative effects in a climate model

Cherian

Quaas

Salzmann

et al. 2017

Tellus B: Chemical and Physical Meteorology

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The aerosol-cloud interactions due to black carbon (BC) aerosols, as well as the implied climate responses, are examined using an aerosol module in the coupled atmosphere-ocean general circulation model MPI-ESM. BC is simulated to enhance cloud droplet number concentration (CDNC) by 10-15% in the BC emission source regions, especially in the Tropics and mid-latitudes. Higher CDNC and reduced auto-conversion from cloud water to rain water explains the increased cloud water path over the tropical regions (30 • S-30 • N) in the model. In the global mean, the cloud wateras well as precipitation changes are negligibly small. The global-mean effective radiative forcing due to aerosol-cloud interactions for BC is estimated at −0.13 ± 0.1 W m −2 , which is attributable to the increase in CDNC burden and (regionally) cloud water in the model. Global mean temperature and rainfall response were found to be −0.16 ± 0.04 K and −0.004 ± 0.004 mm day −1 , respectively, with significantly larger regional changes mainly in the downwind regions from BC sources.

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“…The iteration next simultaneously calculates and assigns the trajectories to the eventually merged clusters. This analysis has been widely used to identify the main transport pathways of air mass (Markou and Kassomenos, 2010;Philipp, 2009;Jorba et al, 2004;Grivas et al, 2008) and is performed using the built-in module in the HYSPLIT model software.…”

Section: Site Description Meteorology Cluster Classificationmentioning

confidence: 99%

“…Microphysical properties of BC importantly determine its optical and hygroscopic properties. For example, the presence of coatings associated with refractory BC (rBC) may enhance its absorbing capacity (Liu et al, 2017) and also enhance its hygroscopicity (Liu et al, 2013) and particle size, thereby modifying the potential to be droplet activated (Chuang et al, 2002;Panicker et al, 2016;Ding et al, 2019b). This study for the first time characterizes the detailed BC microphysics at a mountain site located at the top of the PBL, influenced by surface emission on a daily basis over the NCP region.…”

Section: Introductionmentioning

confidence: 99%

Optical and hygroscopic properties of black carbon influenced by particle microphysics at the top of the anthropogenically polluted boundary layer

et al. 2021

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Abstract. Aerosols at the top of the planetary boundary layer (PBL) could modify its atmospheric dynamics by redistributing the solar radiation and start to be activated to form low-level cloud at this layer. Black carbon (BC), as an aerosol component efficiently absorbing solar radiation, can introduce heating and positive radiative effects at this sensitive layer, especially in the polluted PBL over the continent. This study presents continuous measurements of detailed BC properties at a mountain site located at the top of the polluted PBL over the North China Plain, during seasons (3 and 4 weeks of data during winter and summer, respectively) with contrasting emission structure and meteorology. The pollution level was persistently influenced by local surface anthropogenic emission on a daily basis through daytime convective mixing, but the concentration was also enhanced or diluted depending on air mass direction, defined as a neutral, polluted and diluted PBL, respectively. Winter was observed to have a higher BC mass fraction (4 %–8 %) than summer (2 %–7 %). By resolving the detailed particle size-resolved mixing state of BC in optical and hygroscopic models, we found an enhanced BC mass absorption cross section (MACBC) for the polluted PBL (up to 13 m2 g−1 at λ = 550 nm), which was 5 % higher during summer than winter due to a smaller BC core size. The higher BC mass fraction in winter corresponded to a lower single-scattering albedo by 0.03–0.09 than summer, especially the lowest for the diluted winter PBL (0.86 ± 0.02). The water supersaturation (SS) required to activate half the number of BC decreased from 0.21 % ± 0.08 % to 0.1 % ± 0.03 % for the winter diluted and polluted PBL and from 0.22 % ± 0.06 % to 0.17 % ± 0.05 % for summer. Notably, at the top of the anthropogenically polluted PBL in both seasons, the enlarged BC with enhanced absorption capacity could also be efficiently droplet activated; e.g. winter (summer) BC with an MAC of 9.84 ± 1.2 (10.7 ± 1) m2 g−1 could be half activated at SS = 0.13 % ± 0.06 % (0.18 % ± 0.05 %). This BC at the top of the PBL can more directly interact with the free troposphere and be transported to a wider region, exerting important direct and indirect radiative impacts.

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Indirect forcing of black carbon on clouds over northeast India

Cited by 7 publications

References 36 publications

Size-Related Physical Properties of Black Carbon in the Lower Atmosphere over Beijing and Europe

Size-Related Physical Properties of Black Carbon in the Lower Atmosphere over Beijing and Europe

Black carbon indirect radiative effects in a climate model

Optical and hygroscopic properties of black carbon influenced by particle microphysics at the top of the anthropogenically polluted boundary layer

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