scholarly journals Deposition of ionic species and black carbon to the Arctic snow pack: Combining snow pit observations with modeling

2019 ◽  
Author(s):  
Hans-Werner Jacobi ◽  
Friedrich Obleitner ◽  
Sophie Da Costa ◽  
Patrick Ginot ◽  
Kostas Eleftheriadis ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Aerosols ◽  
Wet Deposition ◽  
Regional Climate ◽  
Ionic Species ◽  
Sea Salt ◽  
The Arctic ◽  
Winter Period ◽  
Snow Pack ◽  
Aerosol Formation

Abstract. Although aerosols in the Arctic have multiple and complex impacts on the regional climate, their removal due to deposition is still not well quantified. We combined meteorological, aerosol, precipitation, and snow pack observations with simulations to derive information about the deposition of sea salt components and black carbon (BC) from November 2011 to April 2012 to the Arctic snow pack at two locations close to Ny-Ålesund, Svalbard. The dominating role of sea salt and the contribution of dust for the composition of atmospheric aerosols were reflected in the seasonal composition of the snow pack. The strong alignment of the concentrations of the major sea salt components in the aerosols, the precipitation, and the snow pack is linked to the importance of wet deposition for the transfer from the atmosphere to the snow pack. This agreement was less strong for monthly snow budgets and deposition indicating important relocation of the impurities inside the snow pack after deposition. Wet deposition was less important for the transfer of nitrate, non sea salt-sulfate, and BC to the snow during the winter period. The average BC concentration in the snow pack remains small with a limited impact on snow albedo and melting. Nevertheless, the observations also indicate an important redistribution of BC in the snowpack leading to layers with enhanced concentrations. The complex behavior of bromide due to modifications during the sea salt aerosol formation and remobilization in the atmosphere and in the snow were not resolved due to the lack of measurements in aerosols and precipitation.

scholarly journals Deposition of ionic species and black carbon to the Arctic snowpack: combining snow pit observations with modeling

2019 ◽  
Vol 19 (15) ◽  
pp. 10361-10377 ◽  
Author(s):  
Hans-Werner Jacobi ◽  
Friedrich Obleitner ◽  
Sophie Da Costa ◽  
Patrick Ginot ◽  
Konstantinos Eleftheriadis ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Aerosols ◽  
Wet Deposition ◽  
Regional Climate ◽  
Ionic Species ◽  
Sea Salt ◽  
The Arctic ◽  
Winter Period ◽  
Aerosol Formation ◽  
Sea Salt Aerosol

Abstract. Although aerosols in the Arctic have multiple and complex impacts on the regional climate, their removal due to deposition is still not well quantified. We combined meteorological, aerosol, precipitation, and snowpack observations with simulations to derive information about the deposition of sea salt components and black carbon (BC) from November 2011 to April 2012 to the Arctic snowpack at two locations close to Ny-Ålesund, Svalbard. The dominating role of sea salt and the contribution of dust for the composition of atmospheric aerosols were reflected in the seasonal composition of the snowpack. The strong alignment of the concentrations of the major sea salt components in the aerosols, the precipitation, and the snowpack is linked to the importance of wet deposition for transfer from the atmosphere to the snowpack. This agreement was less strong for monthly snow budgets and deposition, indicating important relocation of the impurities inside the snowpack after deposition. Wet deposition was less important for the transfer of nitrate, non-sea-salt sulfate, and BC to the snow during the winter period. The average BC concentration in the snowpack remains small, with a limited impact on snow albedo and melting. Nevertheless, the observations also indicate an important redistribution of BC in the snowpack, leading to layers with enhanced concentrations. The complex behavior of bromide due to modifications during sea salt aerosol formation and remobilization in the atmosphere and in the snow were not resolved because of the lack of bromide measurements in aerosols and precipitation.

scholarly journals Four-dimensional variational inversion of black carbon emissions during ARCTAS-CARB with WRFDA-Chem

2017 ◽  
Vol 17 (12) ◽  
pp. 7605-7633 ◽  
Author(s):  
Jonathan J. Guerrette ◽  
Daven K. Henze
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Degrees Of Freedom ◽  
Variance Reduction ◽  
Regional Climate ◽  
The Arctic ◽  
Near Surface ◽  
Fire Emissions ◽  
Aircraft Observations

Abstract. Biomass burning emissions of atmospheric aerosols, including black carbon, are growing due to increased global drought, and comprise a large source of uncertainty in regional climate and air quality studies. We develop and apply new incremental four-dimensional variational (4D-Var) capabilities in WRFDA-Chem to find optimal spatially and temporally distributed biomass burning (BB) and anthropogenic black carbon (BC) aerosol emissions. The constraints are provided by aircraft BC concentrations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites in collaboration with the California Air Resources Board (ARCTAS-CARB) field campaign and surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network on 22, 23, and 24 June 2008. We consider three BB inventories, including Fire INventory from NCAR (FINN) v1.0 and v1.5 and Quick Fire Emissions Database (QFED) v2.4r8. On 22 June, aircraft observations are able to reduce the spread between a customized QFED inventory and FINNv1.0 from a factor of 3. 5 ( × 3. 5) to only × 2. 1. On 23 and 24 June, the spread is reduced from × 3. 4 to × 1. 4. The posterior corrections to emissions are heterogeneous in time and space, and exhibit similar spatial patterns of sign for both inventories. The posterior diurnal BB patterns indicate that multiple daily emission peaks might be warranted in specific regions of California. The US EPA's 2005 National Emissions Inventory (NEI05) is used as the anthropogenic prior. On 23 and 24 June, the coastal California posterior is reduced by × 2, where highway sources dominate, while inland sources are increased near Barstow by × 5. Relative BB emission variances are reduced from the prior by up to 35 % in grid cells close to aircraft flight paths and by up to 60 % for fires near surface measurements. Anthropogenic variance reduction is as high as 40 % and is similarly limited to sources close to observations. We find that the 22 June aircraft observations are able to constrain approximately 14 degrees of freedom of signal (DOF), while surface and aircraft observations together on 23/24 June constrain 23 DOF. Improving hourly- to daily-scale concentration predictions of BC and other aerosols during BB events will require more comprehensive and/or targeted measurements and a more complete accounting of sources of error besides the emissions.

scholarly journals Four dimensional variational inversion of black carbon emissions during ARACTAS-CARB with WRFDA-Chem

2016 ◽  
Author(s):  
Jonathan J. Guerrette ◽  
Daven K. Henze
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Degrees Of Freedom ◽  
Variance Reduction ◽  
Regional Climate ◽  
The Arctic ◽  
Near Surface ◽  
Fire Emissions ◽  
Aircraft Observations

Abstract. Biomass burning emissions of atmospheric aerosols, including black carbon, are growing due to increased global drought, and comprise a large source of uncertainty in regional climate and air quality studies. We develop and apply new incremental 4D-Var capabilities in WRFDA-Chem to find optimal spatially and temporally distributed biomass burning (BB) and anthropogenic black carbon (BC) aerosol emissions. The constraints are provided by aircraft BC concentrations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites in collaboration with the California Air Resources Board (ARCTAS-CARB) field campaign and surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network on 22, 23, and 24 June, 2008. We consider multiple BB inventories, including Fire INventory from NCAR (FINN) v1.0 and v1.5 and Quick Fire Emissions Database (QFED) v2.4r8. On 22 June, aircraft observations are able to reduce the spread between QFED × ⅓ and FINNv1.0 from ×3.5 to ×2.1. On 23 and 24 June, the spread is reduced from ×3.4 to ×1.4. The posterior corrections to emissions are heterogenous in time and space, and exhibit similar spatial patterns of sign for both inventories. The posterior diurnal BB patterns indicate that multiple daily emission peaks might be warranted in specific regions of California. The U.S. EPA's 2005 National Emissions Inventory (NEI05) is used as the anthropogenic prior. On 23 and 24 June, the coastal California posterior is scaled by × ½, where highway sources dominate, while inland sources are increased near Barstow by ×5. Relative BB emission variances are reduced from the prior by up to 35 % in grid cells close to aircraft flight paths and up to 60 % for fires near surface measurements. Anthropogenic variance reduction is as high as 40 % and is similarly limited to sources close to observations. We find that the 22 June aircraft observations are able to constrain approximately 14 degrees of freedom of signal (DOF), while surface and aircraft observations together on 23/24 June constrain 23 DOF. Improving hourly to daily scale concentration predictions of BC and other aerosols during BB events will require more comprehensive and/or targeted measurements and a more complete accounting of sources of error besides the emissions.

scholarly journals Supplementary material to "Deposition of ionic species and black carbon to the Arctic snow pack: Combining snow pit observations with modeling"

2019 ◽  
Author(s):  
Hans-Werner Jacobi ◽  
Friedrich Obleitner ◽  
Sophie Da Costa ◽  
Patrick Ginot ◽  
Kostas Eleftheriadis ◽  
...  
Keyword(s):  
Black Carbon ◽  
Ionic Species ◽  
The Arctic ◽  
Snow Pack ◽  
Supplementary Material

scholarly journals A characterization of Arctic aerosols on the basis of aerosol optical depth and black carbon measurements

Elem Sci Anth ◽  
2014 ◽  
Vol 2 ◽  
Author(s):  
R. S. Stone ◽  
S. Sharma ◽  
A. Herber ◽  
K. Eleftheriadis ◽  
D. W. Nelson
Keyword(s):  
Black Carbon ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Atmospheric Aerosols ◽  
Surface Radiation ◽  
Radiation Budget ◽  
The Arctic ◽  
Carbonaceous Particles ◽  
Surface Warming ◽  
Soot Deposition

Abstract Aerosols, transported from distant source regions, influence the Arctic surface radiation budget. When deposited on snow and ice, carbonaceous particles can reduce the surface albedo, which accelerates melting, leading to a temperature-albedo feedback that amplifies Arctic warming. Black carbon (BC), in particular, has been implicated as a major warming agent at high latitudes. BC and co-emitted aerosols in the atmosphere, however, attenuate sunlight and radiatively cool the surface. Warming by soot deposition and cooling by atmospheric aerosols are referred to as “darkening” and “dimming” effects, respectively. In this study, climatologies of spectral aerosol optical depth AOD (2001–2011) and Equivalent BC (EBC) (1989–2011) from three Arctic observatories and from a number of aircraft campaigns are used to characterize Arctic aerosols. Since the 1980s, concentrations of BC in the Arctic have decreased by more than 50% at ground stations where in situ observations are made. AOD has increased slightly during the past decade, with variations attributed to changing emission inventories and source strengths of natural aerosols, including biomass smoke and volcanic aerosol, further influenced by deposition rates and airflow patterns.

scholarly journals Influence of cloud microphysical processes on black carbon wet removal, global distributions, and radiative forcing

2019 ◽  
Vol 19 (3) ◽  
pp. 1587-1603 ◽  
Author(s):  
Jiayu Xu ◽  
Jiachen Zhang ◽  
Junfeng Liu ◽  
Kan Yi ◽  
Songlin Xiang ◽  
...  
Keyword(s):  
Black Carbon ◽  
Wet Deposition ◽  
Radiative Forcing ◽  
Cloud Water ◽  
Ice Nucleation ◽  
The Arctic ◽  
Cloud Microphysical Processes ◽  
Vertical Distributions ◽  
Microphysical Processes ◽  
Wet Removal

Abstract. Parameterizations that impact wet removal of black carbon (BC) remain uncertain in global climate models. In this study, we enhance the default wet deposition scheme for BC in the Community Earth System Model (CESM) to (a) add relevant physical processes that were not resolved in the default model and (b) facilitate understanding of the relative importance of various cloud processes on BC distributions. We find that the enhanced scheme greatly improves model performance against HIPPO observations relative to the default scheme. We find that convection scavenging, aerosol activation, ice nucleation, evaporation of rain or snow, and below-cloud scavenging dominate wet deposition of BC. BC conversion rates for processes related to in-cloud water–ice conversion (i.e., riming, the Bergeron process, and evaporation of cloud water sedimentation) are relatively smaller, but have large seasonal variations. We also conduct sensitivity simulations that turn off each cloud process one at a time to quantify the influence of cloud processes on BC distributions and radiative forcing. Convective scavenging is found to have the largest impact on BC concentrations at mid-altitudes over the tropics and even globally. In addition, BC is sensitive to all cloud processes over the Northern Hemisphere at high latitudes. As for BC vertical distributions, convective scavenging greatly influences BC fractions at different altitudes. Suppressing BC droplet activation in clouds mainly decreases the fraction of column BC below 5 km, whereas suppressing BC ice nucleation increases that above 10 km. During wintertime, the Bergeron process also significantly increases BC concentrations at lower altitudes over the Arctic. Our simulation yields a global BC burden of 85 Gg; corresponding direct radiative forcing (DRF) of BC estimated using the Parallel Offline Radiative Transfer (PORT) is 0.13 W m−2, much lower than previous studies. The range of DRF derived from sensitivity simulations is large, 0.09–0.33 W m−2, corresponding to BC burdens varying from 73 to 151 Gg. Due to differences in BC vertical distributions among each sensitivity simulation, fractional changes in DRF (relative to the baseline simulation) are always higher than fractional changes in BC burdens; this occurs because relocating BC in the vertical influences the radiative forcing per BC mass. Our results highlight the influences of cloud microphysical processes on BC concentrations and radiative forcing.

scholarly journals The Chemical Characteristics of Snow Cover in a Northern Boreal Forest During the Spring Run-Off Period

1985 ◽  
Vol 7 ◽  
pp. 167-174
Author(s):  
H.G. Jones ◽  
W. Sochanska
Keyword(s):  
Boreal Forest ◽  
Snow Cover ◽  
Atmospheric Aerosols ◽  
Organic Material ◽  
Wet Deposition ◽  
Ionic Species ◽  
Mean Value ◽  
Exchange Capacity ◽  
Mean Values ◽  
Organic Debris

An intensive snow-cover survey at Lake Laflamme, Quebec, during the spring of 1983 showed that wet deposition in the form of rain, which was a dominant phenomenon during the 1983 melt season, gave rise, according to the intensity and chemical quality of the precipitation, to both losses and gains of ion loads (meq m−2) in the snowpack. Mean values for the daily wet deposition loadings (meq m−2 d−1) of ionic species associated with atmospheric aerosols (H+, , ) were of approximately the same magnitude as the daily changes in gains recorded in the snow cover during the melt period. In contrast, the mean value for the contribution by wet deposition to the total loads of K+ and in the snow cover was far outweighed by the gains which were observed at the same time. The expected losses for the snowpack, calculated from the sum of the total loads stocked in the pack at the beginning of the melt period and the total loads in precipitation during the melt period, were lower than the sum of the actual losses observed for all ionic species except H+. The increases (%) in the loads for the major anions Cl−, and were comparable (25 to 32%). The results suggested that dry deposition either directly by aerosol interaction with the snow cover or indirectly by adsorption on organic material followed by leaching during the melt period, or by a combination of both, was a major factor in the increases observed. The values for the increases in loads for Ca2+, , Mg2+ and Na+ (50 to 287%) probably represented, in addition to leaching of local debris, the exudates of cellular material from the cell plasmolysis of detrital organic debris. High rates of in-pack production, however, were characteristic of Al3+. Mn2+, K+ and which showed substantial increases in pack loads (480 to 750%). These increases cannot be accounted for by any local phenomena other than the dissolution or microbiological degradation of organic debris. It is suggested that ion exchange capacity of both particulate and soluble organic material led to a decrease in pack acidity; this phenomenon should thus be considered as a major factor in all attempts to model acid rain fluxes through boreal forest systems.

scholarly journals Responses of Arctic Black Carbon and Surface Temperature to Multi-Region Emission Reductions: an HTAP2 Ensemble Modeling Study

2020 ◽  
Author(s):  
Na Zhao ◽  
Xinyi Dong ◽  
Joshua S. Fu ◽  
Marianne Tronstad Lund ◽  
Kengo Sudo ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Black Carbon ◽  
Task Force ◽  
Regional Climate ◽  
The Arctic ◽  
Ensemble Modeling ◽  
Emission Reductions ◽  
Transport Pathways ◽  
Source Regions ◽  
The Impact

Abstract. Black carbon (BC) emissions play an important role in regional climate change of the Arctic. It is necessary to pay attention to the impact of long-range transport from regions outside the Arctic as BC emissions from local sources in the Arctic were relatively small. The Task Force Hemispheric Transport of Air Pollution Phase2 (HTAP2) set up a series of simulation scenarios to investigate the response of BC in a given region to different source regions. This study investigated the responses of Arctic BC concentrations and surface temperature to 20 % anthropogenic emission reductions from six regions in 2010 within the framework of HTAP2 based on ensemble modeling results. It was found that the emissions from East Asia (EAS) had most (18.1 %–51.4 %) significant impact on the Arctic while the monthly contributions from Europe, Middle East, North America, Russia Belarus Ukraine, and South Asia were 20.1 %–49.9 %, 0.02 %–0.9 %, 8.3 %–19.3 %, 5.4 %–18.1 %, and 3.1 %–7.7 %, respectively. The responses of the vertical profiles of the Arctic BC to the six regions were found to be different due to multiple transport pathways. The response of the Arctic BC to emission reductions of six source regions became less significant with the increase of the latitude. The benefit of BC emission reductions in terms of slowing down surface warming in the Arctic was evaluated by using Absolute Regional Temperature-change Potential (ARTP). Compared to the response of global temperature to BC emission reductions, the response of Arctic temperature was substantially more sensitive, highlighting the need for curbing global BC emissions.

scholarly journals Change in global aerosol composition since preindustrial times

2006 ◽  
Vol 6 (3) ◽  
pp. 5585-5628 ◽  
Author(s):  
K. Tsigaridis ◽  
M. Krol ◽  
F. J. Dentener ◽  
Y. Balkanski ◽  
J. Lathière ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Atmospheric Aerosols ◽  
Transport Model ◽  
Sea Salt ◽  
Carbonaceous Aerosol ◽  
Aerosol Formation ◽  
Aerosol Composition ◽  
Aerosol Mass ◽  
Composition Changes ◽  
Aerosol Chemical Composition

Abstract. To elucidate human induced changes of aerosol load and composition in the atmosphere, a coupled aerosol and gas-phase chemistry transport model of the troposphere and lower stratosphere has been used. This is the first 3-d modeling study that focuses on aerosol chemical composition change since preindustrial times considering the secondary organic aerosol formation together with all other main aerosol components including nitrate. In particular, we evaluate non-sea-salt sulfate (nss-SO4=), ammonium (NH4+), nitrate (NO3-), black carbon (BC), sea-salt, dust, primary and secondary organics (POA and SOA) with a focus on the importance of secondary organic aerosols. Our calculations show that the aerosol optical depth (AOD) has increased by about 21% since preindustrial times. This enhancement of AOD is attributed to a rise in the atmospheric load of BC, nss-SO4=, NO3-, POA and SOA by factors of 3.3, 2.6, 2.7, 2.3 and 1.2, respectively, whereas we assumed that the natural dust and sea-salt sources remained constant. The nowadays increase in carbonaceous aerosol loading is dampened by a 34–42% faster conversion of hydrophobic to hydrophilic carbonaceous aerosol leading to higher removal rates. These changes between the various aerosol components resulted in significant modifications of the aerosol chemical composition. The relative importance of the various aerosol components is critical for the aerosol climatic effect, since atmospheric aerosols behave differently when their chemical composition changes. According to this study, the aerosol composition changed significantly over the different continents and with height since preindustrial times. The presence of anthropogenically emitted primary particles in the atmosphere facilitates the condensation of the semi-volatile species that form SOA onto the aerosol phase, particularly in the boundary layer. The SOA burden that is dominated by the natural component has increased by 24% while its contribution to the AOD has increased by 11%. The increase in oxidant levels and preexisting aerosol mass since preindustrial times is the reason of the burden change, since emissions have not changed significantly. The computed aerosol composition changes translate into about 2.5 times more water associated with non sea-salt aerosol. Additionally, aerosols contain 2.7 times more inorganic components nowadays than during the preindustrial times. We find that the increase in emissions of inorganic aerosol precursors is much larger than the corresponding aerosol increase, reflecting a non-linear atmospheric response.

scholarly journals Technical note: Sea salt interference with black carbon quantification in snow samples using the single particle soot photometer

2021 ◽  
Vol 21 (12) ◽  
pp. 9329-9342
Author(s):  
Marco Zanatta ◽  
Andreas Herber ◽  
Zsófia Jurányi ◽  
Oliver Eppers ◽  
Johannes Schneider ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Single Particle ◽  
Detection Efficiency ◽  
Sea Salt ◽  
The Arctic ◽  
Mass Detection ◽  
High Concentration ◽  
The Impact ◽  
Snow Samples

Abstract. After aerosol deposition from the atmosphere, black carbon (BC) takes part in the snow albedo feedback contributing to the modification of the Arctic radiative budget. With the initial goal of quantifying the concentration of BC in the Arctic snow and subsequent climatic impacts, snow samples were collected during the research vessel (R/V) Polarstern expedition of PASCAL (Physical Feedbacks of Arctic Boundary Layer, Sea Ice, Cloud and Aerosol; Polarstern cruise 106) in the sea-ice-covered Fram Strait in early summer 2017. The refractory BC (rBC) content was then measured in the laboratory of the Alfred Wegener Institute with the single particle soot photometer (SP2). Based on the strong observational correlations between both rBC concentration and rBC diameter with snow salinity, we hypothesize a salt-induced matrix effect interfering with the SP2 analysis. This paper evaluates the impact of sea salt, based on the measurement of electrical conductivity (κ) in water samples, on rBC measurements made with a SP2 nebulizer technique. Under realistic salinity conditions, laboratory experiments indicated a dramatic six-fold reduction in observed rBC concentration with increasing salinity. In the salinity conditions tested in the present work (salt concentration below 0.4 g L−1) the impact of salt on the nebulization of water droplets might be negligible. However, the SP2 mass detection efficiency systematically decreased with increasing salinity, with the smaller rBC particles being preferentially undetected. The high concentration of suspended salt particles and the formation of thick salt coatings on rBC cores caused problems in the SP2 analog-to-digital conversion of the signal and incandescence quenching, respectively. Changes to the signal acquisition parameters and the laser power of the SP2 improved the mass detection efficiency, which, nonetheless, stayed below unity. The present work provides evidence that a high concentration of sea salt undermines the quantification of rBC in snow performed with the SP2 nebulizer system described here. This interference has not been previously reported and might affect the future such analysis of rBC particles in snow collected, especially over sea ice or coastal regions strongly affected by sea salt deposition.

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