scholarly journals Black carbon in the Arctic: the underestimated role of gas flaring and residential combustion emissions

2013 ◽  
Vol 13 (17) ◽  
pp. 8833-8855 ◽  
Author(s):  
A. Stohl ◽  
Z. Klimont ◽  
S. Eckhardt ◽  
K. Kupiainen ◽  
V. P. Shevchenko ◽  
...  
Keyword(s):  
Black Carbon ◽  
Time Resolution ◽  
The Arctic ◽  
Emission Data ◽  
Data Set ◽  
Gas Flaring ◽  
Residential Combustion ◽  
Combustion Emissions ◽  
High Concentrations

Abstract. Arctic haze is a seasonal phenomenon with high concentrations of accumulation-mode aerosols occurring in the Arctic in winter and early spring. Chemistry transport models and climate chemistry models struggle to reproduce this phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important. We perform a 3 yr model simulation of black carbon (BC) with the Lagrangian particle dispersion model FLEXPART. The model is driven with a new emission data set ("ECLIPSE emissions") which includes emissions from gas flaring. While gas flaring is estimated to contribute less than 3% of global BC emissions in this data set, flaring dominates the estimated BC emissions in the Arctic (north of 66° N). Putting these emissions into our model, we find that flaring contributes 42% to the annual mean BC surface concentrations in the Arctic. In March, flaring even accounts for 52% of all Arctic BC near the surface. Most of the flaring BC remains close to the surface in the Arctic, so that the flaring contribution to BC in the middle and upper troposphere is small. Another important factor determining simulated BC concentrations is the seasonal variation of BC emissions from residential combustion (often also called domestic combustion, which is used synonymously in this paper). We have calculated daily residential combustion emissions using the heating degree day (HDD) concept based on ambient air temperature and compare results from model simulations using emissions with daily, monthly and annual time resolution. In January, the Arctic-mean surface concentrations of BC due to residential combustion emissions are 150% higher when using daily emissions than when using annually constant emissions. While there are concentration reductions in summer, they are smaller than the winter increases, leading to a systematic increase of annual mean Arctic BC surface concentrations due to residential combustion by 68% when using daily emissions. A large part (93%) of this systematic increase can be captured also when using monthly emissions; the increase is compensated by a decreased BC burden at lower latitudes. In a comparison with BC measurements at six Arctic stations, we find that using daily-varying residential combustion emissions and introducing gas flaring emissions leads to large improvements of the simulated Arctic BC, both in terms of mean concentration levels and simulated seasonality. Case studies based on BC and carbon monoxide (CO) measurements from the Zeppelin observatory appear to confirm flaring as an important BC source that can produce pollution plumes in the Arctic with a high BC / CO enhancement ratio, as expected for this source type. BC measurements taken during a research ship cruise in the White, Barents and Kara seas north of the region with strong flaring emissions reveal very high concentrations of the order of 200–400 ng m−3. The model underestimates these concentrations substantially, which indicates that the flaring emissions (and probably also other emissions in northern Siberia) are rather under- than overestimated in our emission data set. Our results suggest that it may not be "vertical transport that is too strong or scavenging rates that are too low" and "opposite biases in these processes" in the Arctic and elsewhere in current aerosol models, as suggested in a recent review article (Bond et al., Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res., 2013), but missing emission sources and lacking time resolution of the emission data that are causing opposite model biases in simulated BC concentrations in the Arctic and in the mid-latitudes.

scholarly journals Why models struggle to capture Arctic Haze: the underestimated role of gas flaring and domestic combustion emissions

2013 ◽  
Vol 13 (4) ◽  
pp. 9567-9613 ◽  
Author(s):  
A. Stohl ◽  
Z. Klimont ◽  
S. Eckhardt ◽  
K. Kupiainen
Keyword(s):  
Time Resolution ◽  
Model Simulation ◽  
Ambient Air ◽  
Particle Dispersion ◽  
The Arctic ◽  
Emission Data ◽  
Data Set ◽  
Gas Flaring ◽  
Combustion Emissions ◽  
Arctic Haze

Abstract. Arctic Haze is a seasonal phenomenon with high concentrations of accumulation-mode aerosols occurring in the Arctic in winter and early spring. Chemistry transport models and climate chemistry models struggle to reproduce this phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important. We perform a 3 yr model simulation of black carbon (BC) with the Lagrangian particle dispersion model FLEXPART. The model is driven with a new emission data set which includes emissions from gas flaring. While gas flaring is estimated to contribute less than 3% of global BC emissions in this data set, flaring dominates the estimated BC emissions in the Arctic (north of 66° N). Putting these emissions into our model, we find that flaring contributes 42% to the annual mean BC surface concentrations in the Arctic. In March, flaring even accounts for 52% of all Arctic BC near the surface. Most of the flaring BC remains close to the surface in the Arctic, so that the flaring contribution to BC in the middle and upper troposphere is small. Another important factor determining simulated BC concentrations is the seasonal variation of BC emissions from domestic combustion. We have calculated daily domestic combustion emissions using the heating degree day (HDD) concept based on ambient air temperature and compare results from model simulations using emissions with daily, monthly and annual time resolution. In January, the Arctic-mean surface concentrations of BC due to domestic combustion emissions are 150% higher when using daily emissions than when using annually constant emissions. While there are concentration reductions in summer, they are smaller than the winter increases, leading to a systematic increase of annual mean Arctic BC surface concentrations due to domestic combustion by 68% when using daily emissions. A large part (93%) of this systematic increase can be captured also when using monthly emissions; the increase is compensated by a decreased BC burden at lower latitudes. In a comparison with BC measurements at six Arctic stations, we find that using daily-varying domestic combustion emissions and introducing gas flaring emissions leads to large improvements of the simulated Arctic BC, both in terms of mean concentration levels and simulated seasonality. Case studies based on BC and carbon monoxide (CO) measurements from the Zeppelin observatory appear to confirm flaring as an important BC source that can produce pollution plumes in the Arctic with a high BC/CO enhancement ratio, as expected for this source type. Our results suggest that it may not be "vertical transport that is too strong or scavenging rates that are too low" and "opposite biases in these processes" in the Arctic and elsewhere in current aerosol models, as suggested in a recent review article (Bond et al., 2013), but missing emission sources and lacking time resolution of the emission data that are causing opposite model biases in simulated BC concentrations in the Arctic and in the mid-latitudes.

scholarly journals Sources of Springtime Surface Black Carbon in the Arctic: An Adjoint Analysis

2017 ◽  
Author(s):  
Ling Qi ◽  
Qinbin Li ◽  
Daven K. Henze ◽  
Hsien-Liang Tseng ◽  
Cenlin He
Keyword(s):  
Natural Gas ◽  
Black Carbon ◽  
Biomass Burning ◽  
Transport Model ◽  
Lower Troposphere ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Anthropogenic Source ◽  
Gas Flaring ◽  
Arctic Front

Abstract. We quantify source contributions to springtime (April 2008) surface black carbon (BC) in the Arctic by interpreting surface observations of BC at five receptor sites (Denali, Barrow, Alert, Zeppelin, and Summit) using a global chemical transport model (GEOS-Chem) and its adjoint. Contributions to BC at Barrow, Alert, and Zeppelin are dominated by Asian anthropogenic sources (40–43 %) before April 18 and by Siberian open biomass burning emissions (29–41 %) afterward. In contrast, Summit, a mostly free tropospheric site, has predominantly an Asian anthropogenic source contribution (24–68 %, with an average of 45 %). We compute the adjoint sensitivity of BC concentrations at the five sites during a pollution episode (April 20–25) to global emissions from March 1 to April 25. The associated contributions are the combined results of these sensitivities and BC emissions. Local and regional anthropogenic sources in Alaska are the largest anthropogenic sources of BC at Denali (63 %), and natural gas flaring emissions in the Western Extreme North of Russia (WENR) are the largest anthropogenic sources of BC at Zeppelin (26 %) and Alert (13 %). We find that long-range transport of emissions from Beijing-Tianjin-Hebei (also known as Jing-Jin-Ji), the biggest urbanized region in Northern China, contribute significantly (~ 10 %) to surface BC across the Arctic. On average it takes ~ 12 days for Asian anthropogenic emissions and Siberian biomass burning emissions to reach Arctic lower troposphere, supporting earlier studies. Natural gas flaring emissions from the WENR reach Zeppelin in about a week. We find that episodic, direct transport events dominate BC at Denali (87 %), a site outside the Arctic front, a strong transport barrier. The relative contribution of direct transport to surface BC within the Arctic front is much smaller (~ 50 % at Barrow and Zeppelin and ~ 10 % at Alert). The large contributions from Asian anthropogenic sources are predominately in the form of ‘chronic’ pollution (~ 40 % at Barrow and 65 % at Alert and 57 % at Zeppelin) on 1–2 month timescales. As such, it is likely that previous studies using 5- or 10-day trajectory analyses strongly underestimated the contribution from Asia to surface BC in the Arctic. Both finer temporal resolution of biomass burning emissions and accounting for the Wegener-Bergeron-Findeisen (WBF) process in wet scavenging improve the source attribution estimates.

scholarly journals Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

2015 ◽  
Vol 15 (16) ◽  
pp. 9413-9433 ◽  
Author(s):  
S. Eckhardt ◽  
B. Quennehen ◽  
D. J. L. Olivié ◽  
T. K. Berntsen ◽  
R. Cherian ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Chemistry ◽  
Emission Inventory ◽  
Dispersion Model ◽  
Measurement Data ◽  
Particle Dispersion ◽  
The Arctic ◽  
Late Winter ◽  
Data Set ◽  
Arctic Haze

Abstract. The concentrations of sulfate, black carbon (BC) and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze) and low values in summer. Models have long been struggling to capture this seasonality and especially the high concentrations associated with Arctic Haze. In this study, we evaluate sulfate and BC concentrations from eleven different models driven with the same emission inventory against a comprehensive pan-Arctic measurement data set over a time period of 2 years (2008–2009). The set of models consisted of one Lagrangian particle dispersion model, four chemistry transport models (CTMs), one atmospheric chemistry-weather forecast model and five chemistry climate models (CCMs), of which two were nudged to meteorological analyses and three were running freely. The measurement data set consisted of surface measurements of equivalent BC (eBC) from five stations (Alert, Barrow, Pallas, Tiksi and Zeppelin), elemental carbon (EC) from Station Nord and Alert and aircraft measurements of refractory BC (rBC) from six different campaigns. We find that the models generally captured the measured eBC or rBC and sulfate concentrations quite well, compared to previous comparisons. However, the aerosol seasonality at the surface is still too weak in most models. Concentrations of eBC and sulfate averaged over three surface sites are underestimated in winter/spring in all but one model (model means for January–March underestimated by 59 and 37 % for BC and sulfate, respectively), whereas concentrations in summer are overestimated in the model mean (by 88 and 44 % for July–September), but with overestimates as well as underestimates present in individual models. The most pronounced eBC underestimates, not included in the above multi-site average, are found for the station Tiksi in Siberia where the measured annual mean eBC concentration is 3 times higher than the average annual mean for all other stations. This suggests an underestimate of BC sources in Russia in the emission inventory used. Based on the campaign data, biomass burning was identified as another cause of the modeling problems. For sulfate, very large differences were found in the model ensemble, with an apparent anti-correlation between modeled surface concentrations and total atmospheric columns. There is a strong correlation between observed sulfate and eBC concentrations with consistent sulfate/eBC slopes found for all Arctic stations, indicating that the sources contributing to sulfate and BC are similar throughout the Arctic and that the aerosols are internally mixed and undergo similar removal. However, only three models reproduced this finding, whereas sulfate and BC are weakly correlated in the other models. Overall, no class of models (e.g., CTMs, CCMs) performed better than the others and differences are independent of model resolution.

scholarly journals Downward particle flux and carbon export in the Beaufort Sea, Arctic Ocean; the role of zooplankton

2015 ◽  
Vol 12 (16) ◽  
pp. 5103-5117 ◽  
Author(s):  
J.-C. Miquel ◽  
B. Gasser ◽  
J. Martín ◽  
C. Marec ◽  
M. Babin ◽  
...  
Keyword(s):  
Carbon Flux ◽  
Late Summer ◽  
Beaufort Sea ◽  
Total Carbon ◽  
The Arctic ◽  
Surface Zone ◽  
Calanoid Copepods ◽  
Data Set ◽  
Faecal Pellets

Abstract. As part of the international, multidisciplinary project Malina, downward particle fluxes were investigated by means of a drifting multi-sediment trap mooring deployed at three sites in the Canadian Beaufort Sea in late summer 2009. Mooring deployments lasted between 28 and 50 h and targeted the shelf-break and the slope along the Beaufort-Mackenzie continental margin, as well as the edge between the Mackenzie Shelf and the Amundsen Gulf. Besides analyses of C and N, the collected material was investigated for pigments, phyto- and microzooplankton, faecal pellets and swimmers. The measured fluxes were relatively low, in the range of 11–54 mg m−2 d−1 for the total mass, 1–15 mg C m−2 d−1 for organic carbon and 0.2–2.5 mg N m−2 d−1 for nitrogen. Comparison with a long-term trap data set from the same sampling area showed that the short-term measurements were at the lower end of the high variability characterizing a rather high flux regime during the study period. The sinking material consisted of aggregates and particles that were characterized by the presence of hetero- and autotrophic microzooplankters and diatoms and by the corresponding pigment signatures. Faecal pellets contribution to sinking carbon flux was important, especially at depths below 100 m, where they represented up to 25 % of the total carbon flux. The vertical distribution of different morphotypes of pellets showed a marked pattern with cylindrical faeces (produced by calanoid copepods) present mainly within the euphotic zone, whereas elliptical pellets (produced mainly by smaller copepods) were more abundant at mesopelagic depths. These features, together with the density of matter within the pellets, highlighted the role of the zooplankton community in the transformation of carbon issued from the primary production and the transition of that carbon from the productive surface zone to the Arctic Ocean's interior. Our data indicate that sinking carbon flux in this late summer period is primarily the result of a heterotrophic-driven ecosystem.

The role of circulation features on black carbon transport into the Arctic in the Community Atmosphere Model version 5 (CAM5)

2013 ◽  
Vol 118 (10) ◽  
pp. 4657-4669 ◽  
Author(s):  
Po-Lun Ma ◽  
Philip J. Rasch ◽  
Hailong Wang ◽  
Kai Zhang ◽  
Richard C. Easter ◽  
...  
Keyword(s):  
Black Carbon ◽  
The Arctic ◽  
Model Version ◽  
Community Atmosphere Model ◽  
Atmosphere Model ◽  
Carbon Transport

scholarly journals FLEXPART v10.1 simulation of source contributions to Arctic black carbon

2020 ◽  
Vol 20 (3) ◽  
pp. 1641-1656 ◽  
Author(s):  
Chunmao Zhu ◽  
Yugo Kanaya ◽  
Masayuki Takigawa ◽  
Kohei Ikeda ◽  
Hiroshi Tanimoto ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Anthropogenic Emissions ◽  
High Altitudes ◽  
Arctic Environment ◽  
Gas Flaring ◽  
Rapid Changes ◽  
Arctic Surface

Abstract. The Arctic environment is undergoing rapid changes such as faster warming than the global average and exceptional melting of glaciers in Greenland. Black carbon (BC) particles, which are a short-lived climate pollutant, are one cause of Arctic warming and glacier melting. However, the sources of BC particles are still uncertain. We simulated the potential emission sensitivity of atmospheric BC present over the Arctic (north of 66∘ N) using the FLEXPART (FLEXible PARTicle) Lagrangian transport model (version 10.1). This version includes a new aerosol wet removal scheme, which better represents particle-scavenging processes than older versions did. Arctic BC at the surface (0–500 m) and high altitudes (4750–5250 m) is sensitive to emissions in high latitude (north of 60∘ N) and mid-latitude (30–60∘ N) regions, respectively. Geospatial sources of Arctic BC were quantified, with a focus on emissions from anthropogenic activities (including domestic biofuel burning) and open biomass burning (including agricultural burning in the open field) in 2010. We found that anthropogenic sources contributed 82 % and 83 % of annual Arctic BC at the surface and high altitudes, respectively. Arctic surface BC comes predominantly from anthropogenic emissions in Russia (56 %), with gas flaring from the Yamalo-Nenets Autonomous Okrug and Komi Republic being the main source (31 % of Arctic surface BC). These results highlight the need for regulations to control BC emissions from gas flaring to mitigate the rapid changes in the Arctic environment. In summer, combined open biomass burning in Siberia, Alaska, and Canada contributes 56 %–85 % (75 % on average) and 40 %–72 % (57 %) of Arctic BC at the surface and high altitudes, respectively. A large fraction (40 %) of BC in the Arctic at high altitudes comes from anthropogenic emissions in East Asia, which suggests that the rapidly growing economies of developing countries could have a non-negligible effect on the Arctic. To our knowledge, this is the first year-round evaluation of Arctic BC sources that has been performed using the new wet deposition scheme in FLEXPART. The study provides a scientific basis for actions to mitigate the rapidly changing Arctic environment.

scholarly journals Sources of springtime surface black carbon in the Arctic: an adjoint analysis for April 2008

2017 ◽  
Vol 17 (15) ◽  
pp. 9697-9716 ◽  
Author(s):  
Ling Qi ◽  
Qinbin Li ◽  
Daven K. Henze ◽  
Hsien-Liang Tseng ◽  
Cenlin He
Keyword(s):  
Natural Gas ◽  
Black Carbon ◽  
Biomass Burning ◽  
Transport Model ◽  
Lower Troposphere ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Anthropogenic Source ◽  
Chemical Transport Model ◽  
Gas Flaring

Abstract. We quantify source contributions to springtime (April 2008) surface black carbon (BC) in the Arctic by interpreting surface observations of BC at five receptor sites (Denali, Barrow, Alert, Zeppelin, and Summit) using a global chemical transport model (GEOS-Chem) and its adjoint. Contributions to BC at Barrow, Alert, and Zeppelin are dominated by Asian anthropogenic sources (40–43 %) before 18 April and by Siberian open biomass burning emissions (29–41 %) afterward. In contrast, Summit, a mostly free tropospheric site, has predominantly an Asian anthropogenic source contribution (24–68 %, with an average of 45 %). We compute the adjoint sensitivity of BC concentrations at the five sites during a pollution episode (20–25 April) to global emissions from 1 March to 25 April. The associated contributions are the combined results of these sensitivities and BC emissions. Local and regional anthropogenic sources in Alaska are the largest anthropogenic sources of BC at Denali (63 % of total anthropogenic contributions), and natural gas flaring emissions in the western extreme north of Russia (WENR) are the largest anthropogenic sources of BC at Zeppelin (26 %) and Alert (13 %). We find that long-range transport of emissions from Beijing–Tianjin–Hebei (also known as Jing–Jin–Ji), the biggest urbanized region in northern China, contribute significantly (∼ 10 %) to surface BC across the Arctic. On average, it takes ∼ 12 days for Asian anthropogenic emissions and Siberian biomass burning emissions to reach the Arctic lower troposphere, supporting earlier studies. Natural gas flaring emissions from the WENR reach Zeppelin in about a week. We find that episodic transport events dominate BC at Denali (87 %), a site outside the Arctic front, which is a strong transport barrier. The relative contribution of these events to surface BC within the polar dome is much smaller (∼ 50 % at Barrow and Zeppelin and ∼ 10 % at Alert). The large contributions from Asian anthropogenic sources are predominately in the form of chronic pollution (∼ 40 % at Barrow, 65 % at Alert, and 57 % at Zeppelin) on about a 1-month timescale. As such, it is likely that previous studies using 5- or 10-day trajectory analyses strongly underestimated the contribution from Asia to surface BC in the Arctic.

scholarly journals Siberian Arctic black carbon: gas flaring and wildfire impact

2021 ◽  
Author(s):  
Olga B. Popovicheva ◽  
Nikolaos Evangeliou ◽  
Vasilii O. Kobelev ◽  
Marina A. Chichaeva ◽  
Konstantinos Eleftheriadis ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Western Siberia ◽  
Oil And Gas ◽  
Cold Period ◽  
The Arctic ◽  
Transport Modelling ◽  
Large Variability ◽  
Gas Flaring ◽  
Siberian Arctic

Abstract. As explained in the latest Arctic Monitoring and Assessment Programme (AMAP) report released in early 2021, the Arctic has warmed three times more quickly than the planet as a whole, and faster than previously thought. The Siberian Arctic is of great interest largely because observations are sparse or largely lacking. A research aerosol station has been developed on the Bely Island, Kara Sea, in Western Siberia. Measurements of equivalent black carbon (EBC) concentrations were carried out at the “Island Bely” station continuously from August 2019 to November 2020. The source origin of the measured EBC, and the main contributing sources were assessed using atmospheric transport modelling coupled with the most updated emission inventories for anthropogenic and biomass burning sources of BC. The obtained BC climatology for BC during the period of measurements showed a seasonal variation comprising the highest concentrations between December and April (60 ± 92 ng/m3) and the lowest between June and September (18 ± 72 ng/m3), typical of the Arctic Haze seasonality reported elsewhere. When air masses arrived at the station through the biggest oil and gas extraction regions of Kazakhstan, Volga-Ural, Komi, Nenets and Western Siberia, BC contribution from gas flaring dominated over domestic, industrial, and traffic sectors, ranging from 47 to 68 %, with a maximum contribution in January. When air was transported from Europe during the cold season, emissions from transportation became important. Accordingly, shipping emissions increased due to the touristic cruise activities and the ice retreat in summertime. Biomass burning (BB) played the biggest role between April and October, contributing 81 % at maximum in June. Long-range transport of BB aerosols appear to induce large variability to the Absorption Ångström Exponent (AAE) with values ranging from 1.2 to 1.4. As regards to the continental contribution to surface BC at the “Island Bely” station, Russian emissions dominated during the whole year, while European and Asian emissions contributed up to 20 % in the cold period. Quantification of several pollution episodes showed an increasing trend in surface concentrations and frequency during the cold period as the station is directly in the Siberian gateway of the highest anthropogenic pollution to the Russian Arctic.

scholarly journals Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

2015 ◽  
Vol 15 (7) ◽  
pp. 10425-10477 ◽  
Author(s):  
S. Eckhardt ◽  
B. Quennehen ◽  
D. J. L. Olivié ◽  
T. K. Berntsen ◽  
R. Cherian ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Chemistry ◽  
Emission Inventory ◽  
Dispersion Model ◽  
Measurement Data ◽  
Particle Dispersion ◽  
The Arctic ◽  
Late Winter ◽  
Data Set ◽  
Arctic Haze

Abstract. The concentrations of sulfate, black carbon (BC) and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze) and low values in summer. Models have long been struggling to capture this seasonality and especially the high concentrations associated with Arctic Haze. In this study, we evaluate sulfate and BC concentrations from eleven different models driven with the same emission inventory against a comprehensive pan-Arctic measurement data set over a time period of two years (2008–2009). The set of models consisted of one Lagrangian particle dispersion model, four chemistry-transport models (CTMs), one atmospheric chemistry-weather forecast model and five chemistry-climate models (CCMs), of which two were nudged to meteorological analyses and three were running freely. The measurement data set consisted of surface measurements of equivalent BC (eBC) from five stations (Alert, Barrow, Pallas, Tiksi and Zeppelin), elemental carbon (EC) from Station Nord and Alert and aircraft measurements of refractory BC (rBC) from six different campaigns. We find that the models generally captured the measured eBC/rBC and sulfate concentrations quite well, compared to past comparisons. However, the aerosol seasonality at the surface is still too weak in most models. Concentrations of eBC and sulfate averaged over three surface sites are underestimated in winter/spring in all but one model (model means for January-March underestimated by 59 and 37% for BC and sulfate, respectively), whereas concentrations in summer are overestimated in the model mean (by 88 and 44% for July–September), but with over- as well as underestimates present in individual models. The most pronounced eBC underestimates, not included in the above multi-site average, are found for the station Tiksi in Siberia where the measured annual mean eBC concentration is three times higher than the average annual mean for all other stations. This suggests an underestimate of BC sources in Russia in the emission inventory used. Based on the campaign data, biomass burning was identified as another cause of the modelling problems. For sulfate, very large differences were found in the model ensemble, with an apparent anti-correlation between modeled surface concentrations and total atmospheric columns. There is a strong correlation between observed sulfate and eBC concentrations with consistent sulfate/eBC slopes found for all Arctic stations, indicating that the sources contributing to sulfate and BC are similar throughout the Arctic and that the aerosols are internally mixed and undergo similar removal. However, only three models reproduced this finding, whereas sulfate and BC are weakly correlated in the other models. Overall, no class of models (e.g., CTMs, CCMs) performed better than the others and differences are independent of model resolution.

scholarly journals Flexpart v10.1 simulation of source contributions to Arctic black carbon

2019 ◽  
Author(s):  
Chunmao Zhu ◽  
Yugo Kanaya ◽  
Masayuki Takigawa ◽  
Kohei Ikeda ◽  
Hiroshi Tanimoto ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Anthropogenic Emissions ◽  
High Altitudes ◽  
Arctic Environment ◽  
Gas Flaring ◽  
Rapid Changes ◽  
Arctic Surface

Abstract. The Arctic environment is undergoing rapid changes such as faster warming than the global average and exceptional melting of glaciers in Greenland. Black carbon (BC) particles, which are a short-lived climate pollutant, are one cause of Arctic warming and glacier melting. However, the sources of BC particles are still uncertain. We simulated the potential emission sensitivity of atmospheric BC present over the Arctic (north of 66° N) using the Flexpart Lagrangian transport model (version 10.1). This version includes a new aerosol wet removal scheme, which better represents particle-scavenging processes than older versions did. Arctic BC at the surface (0–500 m) and high altitudes (4750–5250 m) is sensitive to emissions in high latitude (> 60° N) and mid-latitude (30–60° N) regions, respectively. Geospatial sources of Arctic BC were quantified, with a focus on emissions from anthropogenic activities and biomass burning in 2010. We found that anthropogenic sources contributed 82 % and 83 % of annual Arctic BC at the surface and high altitudes, respectively. Arctic surface BC comes predominantly from anthropogenic emissions in Russia (56 %), with gas flaring from the Yamalo-Nenets Autonomous Okrug and Komi Republic being the main source (31 % of Arctic surface BC). These results highlight the need for regulations to control BC emissions from gas flaring to mitigate the rapid changes in the Arctic environment. In summer, combined biomass burning in Siberia, Alaska, and Canada contributes 56–85 % (75 % on average) and 40–72 % (57 %) of Arctic BC at the surface and high altitudes, respectively. A large fraction (40 %) of BC in the Arctic at high altitudes comes from anthropogenic emissions in East Asia, which suggests that the rapidly growing economies of developing countries could have a non-negligible effect on the Arctic. To our knowledge, this is the first year-round evaluation of Arctic BC sources that has been performed using the new wet deposition scheme in Flexpart. The study provides a scientific basis for actions to mitigate the rapidly changing Arctic environment.

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