scholarly journals Aircraft observations of enhancement and depletion of black carbon mass in the springtime Arctic

2010 ◽  
Vol 10 (19) ◽  
pp. 9667-9680 ◽  
Author(s):  
J. R. Spackman ◽  
R. S. Gao ◽  
W. D. Neff ◽  
J. P. Schwarz ◽  
L. A. Watts ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Biomass Burning ◽  
Dry Deposition ◽  
Arctic Climate ◽  
The Arctic ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Air Mass ◽  
The Impact

Abstract. Understanding the processes controlling black carbon (BC) in the Arctic is crucial for evaluating the impact of anthropogenic and natural sources of BC on Arctic climate. Vertical profiles of BC mass loadings were observed from the surface to near 7-km altitude in April 2008 using a Single-Particle Soot Photometer (SP2) during flights on the NOAA WP-3D research aircraft from Fairbanks, Alaska. These measurements were conducted during the NOAA-sponsored Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project. In the free troposphere, the Arctic air mass was influenced by long-range transport from biomass-burning and anthropogenic source regions at lower latitudes especially during the latter part of the campaign. Average BC mass mixing ratios peaked at about 150 ng BC (kg dry air )−1 near 5.5 km altitude in the aged Arctic air mass and 250 ng kg−1 at 4.5 km in biomass-burning influenced air. BC mass loadings were enhanced by up to a factor of 5 in biomass-burning influenced air compared to the aged Arctic air mass. At the bottom of some of the profiles, positive vertical gradients in BC were observed over the sea-ice. The vertical profiles generally occurred in the vicinity of open leads in the sea-ice. In the aged Arctic air mass, BC mass loadings more than doubled with increasing altitude within the ABL and across the boundary layer transition while carbon monoxide (CO) remained constant. This is evidence for depletion of BC mass in the ABL. BC mass loadings were positively correlated with O3 in ozone depletion events (ODEs) for all the observations in the ABL. Since bromine catalytically destroys ozone in the ABL after being released as molecular bromine in regions of new sea-ice formation at the surface, the BC–O3 correlation suggests that BC particles were removed by a surface process such as dry deposition. We develop a box model to estimate the dry deposition flux of BC mass to the snow constrained by the vertical profiles of BC mass in the ABL. Open leads in the sea-ice may increase vertical mixing and entrainment of pollution from the free troposphere possibly enhancing the deposition of BC aerosol to the snow.

scholarly journals Aircraft observations of enhancement and depletion of black carbon mass in the springtime Arctic

2010 ◽  
Vol 10 (6) ◽  
pp. 15167-15196
Author(s):  
J. R. Spackman ◽  
R. S. Gao ◽  
W. D. Neff ◽  
J. P. Schwarz ◽  
L. A. Watts ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Black Carbon ◽  
Biomass Burning ◽  
Boundary Layer Transition ◽  
Arctic Climate ◽  
The Arctic ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Air Mass ◽  
The Impact

Abstract. Understanding the processes controlling black carbon (BC) in the Arctic is crucial for evaluating the impact of anthropogenic and natural sources of BC on Arctic climate. Vertical profiles of BC mass were observed from the surface to near 7-km altitude in April 2008 using a Single-Particle Soot Photometer (SP2) during flights on the NOAA WP-3D research aircraft from Fairbanks, Alaska. These measurements were conducted during the NOAA-sponsored Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) project as part of POLARCAT, an International Polar Year (IPY) activity. In the free troposphere, the Arctic air mass was influenced by long-range transport from biomass-burning and anthropogenic source regions at lower latitudes especially during the latter part of the campaign. Maximum average BC mass loadings of 150 ng kg−1 were observed near 5.5-km altitude in the aged Arctic air mass. In biomass-burning plumes, BC was enhanced from near the top of the Arctic boundary layer (ABL) to 5.5 km compared to the aged Arctic air mass. At the bottom of some of the profiles, positive vertical gradients in BC were observed in the vicinity of open leads in the sea-ice. BC mass loadings increased by about a factor of two across the boundary layer transition in the ABL in these cases while carbon monoxide (CO) remained constant, evidence for depletion of BC in the ABL. BC mass loadings were positively correlated with O3 in ozone depletion events (ODEs) for all the observations in the ABL suggesting that BC was removed by dry deposition of BC on the snow or ice because molecular bromine, Br2, which photolyzes and catalytically destroys O3, is thought to be released near the open leads in regions of ice formation. We estimate the deposition flux of BC mass to the snow using a box model constrained by the vertical profiles of BC in the ABL. The open leads may increase vertical mixing in the ABL and entrainment of pollution from the free troposphere possibly enhancing the deposition of BC to the snow.

scholarly journals The Arctic response to remote and local forcing of black carbon

2012 ◽  
Vol 12 (7) ◽  
pp. 18379-18418 ◽  
Author(s):  
M. Sand ◽  
T. K. Berntsen ◽  
J. E. Kay ◽  
J. F. Lamarque ◽  
Ø. Seland ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Temperature Response ◽  
Mitigation Strategies ◽  
Arctic Climate ◽  
The Arctic ◽  
Comprehensive Treatment ◽  
Model Calculations ◽  
The Impact ◽  
Ice Fraction

Abstract. Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend on the location of the forcing. We investigate how BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to BC located in the Arctic it self. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to determine how BC transported to the Arctic and BC sources not reaching the Arctic impact the Arctic climate, forcing from BC aerosols is artificially increased by a factor of 10 in different latitude bands in the mid-latitudes (28° N–60° N) and in the Arctic (60° N–90° N), respectively. Estimates of the impact on the Arctic energy budget are represented by analyzing radiation fluxes at the top of the atmosphere, at the surface and at the lateral boundaries. Our calculations show that increased BC forcing in the Arctic atmosphere reduces the surface air temperature in the Arctic with a corresponding increase in the sea-ice fraction, despite the increased planetary absorption of sunlight. The analysis indicates that this effect may be due to a combination of a weakening of the northward heat transport caused by a reduction in the meridional temperature gradient and a reduction in the turbulent mixing of heat downward to the surface. The latter factor is explained by the fact that most of the BC is located in the free troposphere and causes a warming at higher altitudes which increases the static stability in the Arctic. On the other hand we find that BC forcing at the mid-latitudes warms the Arctic surface significantly and decreases the sea-ice fraction. Our model calculations indicate that atmospheric BC forcing outside the Arctic is more important for the Arctic climate change than the forcing in the Arctic itself. Although the albedo effect of BC on snow does show a more regional response to an Arctic forcing, these results suggest that mitigation strategies for the Arctic climate should also address BC sources in locations outside the Arctic even if they do not contribute much to BC in the Arctic.

scholarly journals The Arctic response to remote and local forcing of black carbon

2013 ◽  
Vol 13 (1) ◽  
pp. 211-224 ◽  
Author(s):  
M. Sand ◽  
T. K. Berntsen ◽  
J. E. Kay ◽  
J. F. Lamarque ◽  
Ø. Seland ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Heat Transport ◽  
Mitigation Strategies ◽  
Arctic Climate ◽  
The Arctic ◽  
Comprehensive Treatment ◽  
Model Calculations ◽  
The Impact ◽  
Ice Fraction

Abstract. Recent studies suggest that the Arctic temperature response to black carbon (BC) forcing depend strongly on the location of the forcing. We investigate how atmospheric BC in the mid-latitudes remotely influence the Arctic climate, and compare this with the response to atmospheric BC located in the Arctic itself. In this study, idealized climate simulations are carried out with a fully coupled Earth System Model, which includes a comprehensive treatment of aerosol microphysics. In order to determine how BC transported to the Arctic and BC sources not reaching the Arctic impact the Arctic climate, atmospheric BC concentrations are scaled up in the mid-latitudes (28–60° N) and in the Arctic (60–90° N), respectively. Estimates of the impact on the Arctic energy budget are represented by analyzing radiation fluxes at the top of the atmosphere and at the surface, surface turbulent fluxes, and meridional heat transport in the atmosphere. Our calculations show that increased BC forcing in the Arctic atmosphere reduces the surface air temperature in the Arctic with a corresponding increase in the sea-ice fraction, despite the increased planetary absorption of sunlight. The analysis indicates that this effect is due to a combination of a weakening of the northward heat transport caused by a reduction in the meridional temperature gradient and a dimming at the surface. On the other hand we find that BC forcing at the mid-latitudes warms the Arctic surface significantly and decreases the sea-ice fraction. Our model calculations indicate that atmospheric BC forcing outside the Arctic may be more important for the Arctic climate change than the forcing in the Arctic itself. These results suggest that mitigation strategies for the Arctic climate should also address BC sources in locations outside the Arctic even if they do not contribute much to BC in the Arctic.

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.

The impact of sea-ice dynamics on the Arctic climate system

2003 ◽  
Vol 20 (7-8) ◽  
pp. 741-757 ◽  
Author(s):  
S. Vavrus ◽  
S. P. Harrison
Keyword(s):  
Sea Ice ◽  
Climate System ◽  
Arctic Climate ◽  
The Arctic ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
The Impact

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.

The impact of orbital forcing on the Arctic climate during the Last Interglacial simulated by the IPSL-CM6A-LR model

2020 ◽  
Author(s):  
Marie Sicard ◽  
Masa Kageyama ◽  
Pascale Braconnot ◽  
Sylvie Charbit
Keyword(s):  
Solar Radiation ◽  
Sea Ice ◽  
Arctic Sea Ice ◽  
Arctic Climate ◽  
The Arctic ◽  
Orbital Forcing ◽  
Last Interglacial ◽  
Arctic Sea ◽  
The Impact

<p>The Last Interglacial (129 – 116 ka BP) is a time period with a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the present. In particular, these changes amplify the Arctic climate seasonality. They induce warmer summers and colder winters in the high latitudes of the Northern Hemisphere. Such surface conditions favour a huge retreat of the arctic sea ice cover.<br>In this study, we try to understand how this solar radiation anomaly spreads through the surface and impacts the seasonal arctic sea ice. Using IPSL-CM6A-LR model outputs, we decompose the surface energy budget to identify the role of atmospheric and oceanic key processes beyond 60°N and its changes compared to pre-industrial. We show that solar radiation anomaly is greatly reduced when it reaches the Earth’s surface, which emphasizes the role of clouds and water vapor transport.<br>The results are also compared to other PMIP4-CMIP6 model simulations. We would like to thank PMIP participants for producing and making available their model outputs.</p>

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

2021 ◽  
Author(s):  
Marco Zanatta ◽  
Andreas Herber ◽  
Zsófia Jurányi ◽  
Oliver Eppers ◽  
Johannes Schneider ◽  
...  
Keyword(s):  
Sea Ice ◽  
Black Carbon ◽  
Detection Efficiency ◽  
Sea Salt ◽  
The Arctic ◽  
Signal Acquisition ◽  
Mass Detection ◽  
High Concentration ◽  
The Impact ◽  
Snow Samples

Abstract. After deposition from the atmosphere, black carbon aerosol (BC) takes part in the snow albedo feedback contributing to 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 Polarstern expedition PASCAL (Polarstern cruise 106) in the sea ice covered Fram Strait in early summer 2017. The content of refractory BC (rBC) was then quantified in the laboratory of the Alfred Wegener Institute with the single particles soot photometer (SP2). We found strong correlations between both rBC mass concentration and rBC diameter with snow salinity. Therefore, we formulated the hypothesis of a salt-induced matrix effect interfering with the SP2 analysis. By replicating 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 nebulization of water droplets might be negligible. However, the SP2 mass detection efficiency systematically decreased with salinity, with the smaller rBC particles being preferentially undetected. The high concentration of suspended salt particles and the formation of thick salt coating on rBC cores might have caused problems to the SP2 analog-to-digital conversion of the signal and incandescence quenching, respectively. Changes to signal acquisition parameters and laser power of the SP2 improved the mass detection efficiency, which, nonetheless, never attained unity values. The present work provides the evidence that high concentration of sea salt undermines the quantification of rBC in snow performed with the SP2. This interference was never reported and might affect future analysis of rBC particles in snow collected, especially, over sea ice or coastal regions strongly affected by sea salt deposition.

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.

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