scholarly journals Parameterization of black carbon aging in the OsloCTM2 and implications for regional transport to the Arctic

2011 ◽  
Vol 11 (12) ◽  
pp. 32499-32534 ◽  
Author(s):  
M. T. Lund ◽  
T. Berntsen
Keyword(s):  
Black Carbon ◽  
High Latitude ◽  
Transport Model ◽  
Seasonal Pattern ◽  
Particle Interaction ◽  
Model Performance ◽  
High Arctic ◽  
The Arctic ◽  
The Impact ◽  
Snow And Ice

Abstract. A critical parameter for the atmospheric lifetime of black carbon (BC) aerosols, and hence for the range over which the particles can be transported, is the aging time, i.e. the time before the aerosols become available for removal by wet deposition. This study compares two different parameterizations of BC aging in the chemistry transport model OsloCTM2: (i) a bulk parameterization (BULK) where aging is represented by a constant transfer to hydrophilic mode and (ii) a microphysical module (M7) where aging occurs through particle interaction and where the particle size distribution is accounted for. We investigate the effect of including microphysics on the distribution of BC globally and in the Arctic. We also focus on the impact on estimated contributions to Arctic BC from selected emission source regions. With more detailed microphysics (M7) there are regional and seasonal variations in aging. The aging is slower during high-latitude winter, when the production of sulfate is lower, than in lower latitudes and during summer. High-latitude concentrations of BC are significantly increased during winter compared to BULK. Furthermore, M7 improves the model performance at high Arctic surface stations, especially the accumulation of BC during winter. A proper representation of vertical BC load is important because the climate effects of the aerosols depend on their altitude in the atmosphere. Comparisons with measured vertical profiles indicate that the model generally overestimates the BC load, particularly at higher altitudes, and this overestimation is exacerbated with M7 compared to BULK. Both parameterizations show that north of 65° N emissions in Europe contribute most to atmospheric BC concentration and to BC in snow and ice. M7 leads to a pronounced seasonal pattern in contributions and contributions from Europe and Russia increase strongly during winter compared to BULK. There is generally a small increase in the amount of BC in snow and ice with M7 compared to BULK, but concentrations are still underestimated relative to measurements.

scholarly journals Parameterization of black carbon aging in the OsloCTM2 and implications for regional transport to the Arctic

2012 ◽  
Vol 12 (15) ◽  
pp. 6999-7014 ◽  
Author(s):  
M. T. Lund ◽  
T. Berntsen
Keyword(s):  
Black Carbon ◽  
High Latitude ◽  
Transport Model ◽  
Seasonal Pattern ◽  
Particle Interaction ◽  
Model Performance ◽  
The Arctic ◽  
Source Regions ◽  
The Impact ◽  
Snow And Ice

Abstract. A critical parameter for the atmospheric lifetime of black carbon (BC) aerosols, and hence for the range over which the particles can be transported, is the aging time, i.e. the time before the aerosols become available for removal by wet deposition. This study compares two different parameterizations of BC aging in the chemistry transport model OsloCTM2: (i) A bulk parameterization (BULK) where aging is represented by a constant transfer to hydrophilic mode and (ii) a microphysical module (M7) where aging occurs through particle interaction and where the particle size distribution is accounted for. We investigate the effect of including microphysics on the distribution of BC globally and in the Arctic. We also focus on the impact on estimated contributions to Arctic BC from selected emission source regions. With more detailed microphysics (M7) there are regional and seasonal variations in aging. The aging is slower during high-latitude winter, when the production of sulfate is lower, than in lower latitudes and during summer. High-latitude concentrations of BC are significantly increased during winter compared to BULK. Furthermore, M7 improves the model performance at Arctic surface stations, especially the accumulation of BC during winter. A proper representation of vertical BC load is important because the climate effects of the aerosols depend on their altitude in the atmosphere. Comparisons with measured vertical profiles indicate that the model generally overestimates the BC load, particularly at higher altitudes, and this overestimation is exacerbated with M7 compared to BULK. Both parameterizations show that north of 65° N emissions in Europe contribute most to atmospheric BC concentration and to BC in snow and ice. M7 leads to a pronounced seasonal pattern in contributions and contributions from Europe and Russia increase strongly during winter relative to BULK. There is generally an increase in the amount of BC in snow and ice with M7 compared to BULK. However, in regions where the concentration of BC in snow is strongly underestimated with BULK compared to measurements, this increase with M7 is not sufficient to significantly improve the comparison.

scholarly journals Atmospheric black carbon and sulfate concentrations in Northeast Greenland

2015 ◽  
Vol 15 (16) ◽  
pp. 9681-9692 ◽  
Author(s):  
A. Massling ◽  
I. E. Nielsen ◽  
D. Kristensen ◽  
J. H. Christensen ◽  
L. L. Sørensen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Correlation Coefficient ◽  
Seasonal Pattern ◽  
Maximum Level ◽  
High Arctic ◽  
The Arctic ◽  
Research Station ◽  
Summer Period ◽  
Transport Pathways ◽  
Inorganic Matter

Abstract. Measurements of equivalent black carbon (EBC) in aerosols at the high Arctic field site Villum Research Station (VRS) at Station Nord in North Greenland showed a seasonal variation in EBC concentrations with a maximum in winter and spring at ground level. Average measured concentrations were about 0.067 ± 0.071 for the winter and 0.011 ± 0.009 for the summer period. These data were obtained using a multi-angle absorption photometer (MAAP). A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. Here, measured average concentrations were about 0.485 ± 0.397 for the winter and 0.112 ± 0.072 for the summer period. A correlation between EBC and sulfate concentrations was observed over the years 2011 to 2013 stating a correlation coefficient of R2 = 0.72. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. BC and sulfate are known to have only partly similar sources with respect to their transport pathways when reaching the high Arctic. Aging processes may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon) based on a thermo-optical method were determined and compared to EBC measurements. EBC measurements were generally higher, but a correlation between EC and EBC resulted in a correlation coefficient of R2 = 0.64. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Eulerian Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both EBC/BC and sulfate was observed. Also, the correlation between BC and sulfate concentrations was confirmed based on the model results observed over the years 2011 to 2013 stating a correlation coefficient of R2 = 0.74. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor, albeit significant source.

scholarly journals Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along two years (2011–2012) of field campaign

2016 ◽  
Author(s):  
Luca Ferrero ◽  
David Cappelletti ◽  
Maurizio Busetto ◽  
Mauro Mazzola ◽  
Angelo Lupi ◽  
...  
Keyword(s):  
Size Distribution ◽  
Black Carbon ◽  
High Arctic ◽  
Aerosol Concentration ◽  
The Arctic ◽  
Aerosol Size Distribution ◽  
Vertical Profiles ◽  
Anthropogenic Aerosol ◽  
Haze Pollution ◽  
The Impact

Abstract. In this paper we present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011–2012) and resulted in 200 vertical profiles measured during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground to put on a firmer grounds the analysis of the vertical profiles. The collected experimental data allowed a classification of the vertical profiles into different typologies which allowed to describe a seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behaviour was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude in function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the summer Arctic affecting the climate.

scholarly journals Atmospheric black carbon and sulfate concentrations in Northeast Greenland

2015 ◽  
Vol 15 (8) ◽  
pp. 11465-11493 ◽  
Author(s):  
A. Massling ◽  
I. E. Nielsen ◽  
D. Kristensen ◽  
J. H. Christensen ◽  
L. L. Sørensen ◽  
...  
Keyword(s):  
Black Carbon ◽  
Long Range ◽  
Seasonal Pattern ◽  
Maximum Level ◽  
Ground Level ◽  
High Arctic ◽  
The Arctic ◽  
Research Station ◽  
Inorganic Matter ◽  
Transport Patterns

Abstract. Measurements of Black Carbon (BC) in aerosols at the high Arctic field site Villum Research Station (VRS) at Station Nord in North Greenland showed a seasonal variation in BC concentrations with a maximum in winter and spring at ground level. The data was obtained using a Multi Angle Absorption Photometer (MAAP). A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. A correlation between BC and sulfate concentrations was observed over the years 2011 to 2013. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. This process may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon) based on a thermo-optical method were determined and compared to BC measurements. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both BC and sulfate was observed. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor though significant source. During winter and spring the Arctic atmosphere is known to be impacted by long-range transport of BC and associated with the Arctic haze phenomenon.

scholarly journals Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along 2 years (2011–2012) of field campaigns

2016 ◽  
Vol 16 (19) ◽  
pp. 12601-12629 ◽  
Author(s):  
Luca Ferrero ◽  
David Cappelletti ◽  
Maurizio Busetto ◽  
Mauro Mazzola ◽  
Angelo Lupi ◽  
...  
Keyword(s):  
Size Distribution ◽  
Black Carbon ◽  
High Arctic ◽  
Aerosol Concentration ◽  
The Arctic ◽  
Aerosol Size Distribution ◽  
Vertical Profiles ◽  
Anthropogenic Aerosol ◽  
Haze Pollution ◽  
The Impact

Abstract. We present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011–2012) and resulted in 200 vertical profiles measured by means of a tethered balloon (up to 1200 m a.g.l.) during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground. The collected experimental data allowed a classification of the vertical profiles into different typologies, which allowed us to describe the seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behavior was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude as a function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes to be constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the Arctic summer, affecting the climate.

scholarly journals Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling

2019 ◽  
Vol 5 (2) ◽  
pp. eaau8052 ◽  
Author(s):  
P. Winiger ◽  
T. E. Barrett ◽  
R. J. Sheesley ◽  
L. Huang ◽  
S. Sharma ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Climate Warming ◽  
Transport Model ◽  
The Arctic ◽  
Emission Inventories ◽  
Source Contributions ◽  
Model Predictions ◽  
The Impact ◽  
Good Agreement

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer. The annual mean source of BC to the circum-Arctic was 39 ± 10% from biomass burning. Comparison of transport-model predictions with the observations showed good agreement for BC concentrations, with larger discrepancies for (fossil/biomass burning) sources. The accuracy of simulated BC concentration, but not of origin, points to misallocations of emissions in the emission inventories. The consistency in seasonal source contributions of BC throughout the Arctic provides strong justification for targeted emission reductions to limit the impact of BC on climate warming in the Arctic and beyond.

scholarly journals The Rossby radius in the Arctic Ocean

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 967-975 ◽  
Author(s):  
A. J. G. Nurser ◽  
S. Bacon
Keyword(s):  
Arctic Ocean ◽  
General Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
High Arctic ◽  
The Arctic ◽  
Hudson Bay ◽  
Ocean Eddies ◽  
Shelf Seas ◽  
The Impact

Abstract. The first (and second) baroclinic deformation (or Rossby) radii are presented north of ~60° N, focusing on deep basins and shelf seas in the high Arctic Ocean, the Nordic seas, Baffin Bay, Hudson Bay and the Canadian Arctic Archipelago, derived from climatological ocean data. In the high Arctic Ocean, the first Rossby radius increases from ~5 km in the Nansen Basin to ~15 km in the central Canadian Basin. In the shelf seas and elsewhere, values are low (1–7 km), reflecting weak density stratification, shallow water, or both. Seasonality strongly impacts the Rossby radius only in shallow seas, where winter homogenization of the water column can reduce it to below 1 km. Greater detail is seen in the output from an ice–ocean general circulation model, of higher resolution than the climatology. To assess the impact of secular variability, 10 years (2003–2012) of hydrographic stations along 150° W in the Beaufort Gyre are also analysed. The first-mode Rossby radius increases over this period by ~20%. Finally, we review the observed scales of Arctic Ocean eddies.

scholarly journals Sensitivity of black carbon concentrations and climate impact to aging and scavenging

2016 ◽  
Author(s):  
Marianne T. Lund ◽  
Terje K. Berntsen ◽  
Bjørn H. Samset
Keyword(s):  
Nitric Acid ◽  
Black Carbon ◽  
Radiative Forcing ◽  
Mitigation Strategies ◽  
The Arctic ◽  
Climate Mitigation ◽  
Vertical Profiles ◽  
The Impact ◽  
Model Measurement ◽  
Global Mean

Abstract. Despite recent improvements, significant uncertainties in global modeling of black carbon (BC) aerosols persist, posing important challenges for the design and evaluation of effective climate mitigation strategies targeted at BC emission reductions. Here we investigate the sensitivity of BC concentrations in the chemistry-transport model OsloCTM2 with the microphysical aerosol parameterization M7 (OsloCTM2-M7) to parameters controlling aerosol aging and scavenging. We focus on Arctic surface concentrations and remote region BC vertical profiles, and introduce a novel treatment of condensation of nitric acid on BC. The OsloCTM2-M7 underestimates annual averaged BC surface concentrations, with a mean normalized bias of −0.55. The seasonal cycle and magnitude of Arctic BC surface concentrations is improved compared to previous OsloCTM2 studies, but model-measurement discrepancies during spring remain. High-altitude BC over the Pacific is overestimated compared with measurements from the HIPPO campaigns. We find that a shorter global BC lifetime improves the agreement with HIPPO, in line with other recent studies. Several processes can achieve this, including allowing for convective scavenging of hydrophobic BC and reducing the amount of soluble material required for aging. Simultaneously, the concentrations in the Arctic are reduced, resulting in poorer agreement with measurements in part of the region. A first step towards inclusion of aging by nitrate in OsloCTM2-M7 is made by allowing for condensation of nitric acid on BC. This results in a faster aging and reduced lifetime, and in turn to a better agreement with the HIPPO measurements. On the other hand, model-measurement discrepancies in the Arctic are exacerbated. Work to further improve this parameterization is needed. The impact on global mean radiative forcing (RF) and surface temperature response (TS) in our experiments is estimated. Compared to the baseline, decreases in global mean direct RF on the order of 10–30 % of the total pre-industrial to present BC direct RF is estimated for the experiments that result in the largest changes in BC concentrations. We show that globally tuning parameters related to BC aging and scavenging can improve the representation of BC vertical profiles in the OsloCTM2-M7 compared with observations. Our results also show that such improvements can result from changes in several processes and often depend on assumptions about uncertain parameters such as the BC ice nucleating efficiency and the change in hygroscopicity with aging. It is also important to be aware of potential tradeoffs in model performance between different regions. Other important sources of uncertainty, particularly for Arctic BC, such as model resolution has not been investigated here. Our results underline the importance of more observations and experimental data to improve process understanding and thus further constrain models.

scholarly journals A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian High Arctic in winter and spring (1990–2005)

2010 ◽  
Vol 10 (2) ◽  
pp. 2221-2244 ◽  
Author(s):  
L. Huang ◽  
S. L. Gong ◽  
S. Sharma ◽  
D. Lavoué ◽  
C. Q. Jia
Keyword(s):  
Regression Model ◽  
Black Carbon ◽  
North American ◽  
Emission Intensity ◽  
Atmospheric Transport ◽  
High Arctic ◽  
The Arctic ◽  
Canadian High Arctic ◽  
Near Surface ◽  
Annual Variations

Abstract. Black carbon (BC) particles accumulated in the Arctic troposphere and deposited over snow have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, transport pathways affecting Alert (82.5° N, 62.5° W), Nunavut in Canada are identified in this work, along with the associated transport frequency. Based on the atmospheric transport frequency and the estimated BC emission intensity from surrounding regions, a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measured at Alert for both seasons (R2 equals 0.77 and 0.81 for winter and spring, respectively). Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that Eurasia is the major contributor to the near-surface BC levels at the Canadian High Arctic site with an average contribution of over 85% during the 16-year period. In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more predominant with a multi-year average of 94%. The model estimates smaller contribution from the Eurasian sector in spring (70%) than that in winter. It is also found that the change in Eurasian contributions depends mainly on the reduction of emission intensity, while the changes in both emission and atmospheric transport contributed to the inter-annual variation of North American contributions.

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.

Sign in / Sign up

Export Citation Format

Share Document