scholarly journals Chemical composition and source attribution of submicron aerosol particles in the summertime Arctic lower troposphere

2020 ◽  
Author(s):  
Franziska Köllner ◽  
Johannes Schneider ◽  
Megan D. Willis ◽  
Hannes Schulz ◽  
Daniel Kunkel ◽  
...  

Abstract. We use airborne measurements of aerosol particle composition to demonstrate the strong contrast between particle sources and composition within and above the summertime Arctic boundary layer. In-situ measurements from two complementary aerosol mass spectrometers, the ALABAMA and the HR-ToF-AMS, with black carbon measurements from an SP2 are presented. Particle composition analysis was complemented by trace gas measurements, satellite data, and air mass history modeling to attribute particle properties to particle origin and air mass source regions. Particle composition above the summertime Arctic boundary layer was dominated by chemically aged particles, containing elemental carbon, nitrate, ammonium, sulfate, and organic matter. From our analysis, we conclude that the presence of these particles was driven by transport of aerosol and precursor gases from mid-latitudes to Arctic regions. Particularly, elevated concentrations of nitrate, ammonium, and organic matter coincided with time spent over vegetation fires in northern Canada. In parallel, those particles were largely present in high CO environments (> 90 ppbv). Additionally, we observed that the organic-to-sulfate ratio was enhanced with increasing influence from these fires. Besides vegetation fires, particle sources in mid-latitudes further include anthropogenic emissions in Europe, North America, and East Asia. The presence of particles in the Arctic lower free troposphere correlated with time spent over populated and industrial areas in these regions. Further, the size distribution of free tropospheric particles containing elemental carbon and nitrate was shifter to larger diameters compared to particles present within the boundary layer. Moreover, our analysis suggests that organic matter when present in the Arctic free troposphere can partly be identified as low-molecular weight dicarboxylic acids (oxalic, malonic, and succinic acid). Particles containing dicarboxylic acids were largely present when the residence time of air masses outside Arctic regions was high. In contrast, particle composition within the marine boundary layer was largely driven by Arctic regional processes. Air mass history modeling demonstrated that alongside primary sea spray particles, marine-biogenic sources contributed to secondary aerosol formation by trimethylamine, methanesulfonic acid, sulfate, and other organic species.

2021 ◽  
Vol 21 (8) ◽  
pp. 6509-6539
Author(s):  
Franziska Köllner ◽  
Johannes Schneider ◽  
Megan D. Willis ◽  
Hannes Schulz ◽  
Daniel Kunkel ◽  
...  

Abstract. Aerosol particles impact the Arctic climate system both directly and indirectly by modifying cloud properties, yet our understanding of their vertical distribution, chemical composition, mixing state, and sources in the summertime Arctic is incomplete. In situ vertical observations of particle properties in the high Arctic combined with modelling analysis on source attribution are in short supply, particularly during summer. We thus use airborne measurements of aerosol particle composition to demonstrate the strong contrast between particle sources and composition within and above the summertime Arctic boundary layer. In situ measurements from two complementary aerosol mass spectrometers, the Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA) and an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), are presented alongside black carbon measurements from an single particle soot photometer (SP2). Particle composition analysis was complemented by trace gas measurements, satellite data, and air mass history modelling to attribute particle properties to particle origin and air mass source regions. Particle composition above the summertime Arctic boundary layer was dominated by chemically aged particles, containing elemental carbon, nitrate, ammonium, sulfate, and organic matter. From our analysis, we conclude that the presence of these particles was driven by transport of aerosol and precursor gases from mid-latitudes to Arctic regions. Specifically, elevated concentrations of nitrate, ammonium, and organic matter coincided with time spent over vegetation fires in northern Canada. In parallel, those particles were largely present in high CO environments (> 90 ppbv). Additionally, we observed that the organic-to-sulfate ratio was enhanced with increasing influence from these fires. Besides vegetation fires, particle sources in mid-latitudes further include anthropogenic emissions in Europe, North America, and East Asia. The presence of particles in the Arctic lower free troposphere, particularly sulfate, correlated with time spent over populated and industrial areas in these regions. Further, the size distribution of free tropospheric particles containing elemental carbon and nitrate was shifted to larger diameters compared to particles present within the boundary layer. Moreover, our analysis suggests that organic matter, when present in the Arctic free troposphere, can partly be identified as low molecular weight dicarboxylic acids (oxalic, malonic, and succinic acid). Particles containing dicarboxylic acids were largely present when the residence time of air masses outside Arctic regions was high. In contrast, particle composition within the marine boundary layer was largely driven by Arctic regional processes. Air mass history modelling demonstrated that alongside primary sea spray particles, marine biogenic sources contributed to secondary aerosol formation via trimethylamine, methanesulfonic acid, sulfate, and other organic species. Our findings improve our knowledge of mid-latitude and Arctic regional sources that influence the vertical distribution of particle chemical composition and mixing state in the Arctic summer.


2005 ◽  
Vol 5 (1) ◽  
pp. 1067-1114 ◽  
Author(s):  
R. Van Dingenen ◽  
J.-P. Putaud ◽  
S. Martins-Dos Santos ◽  
F. Raes

Abstract. Aerosol physical properties were measured at the Monte Cimone Observatory (Italy) from 1 June till 6 July 2000. The measurement site is located in the transition zone between continental boundary layer and the free troposphere (FT), at the border between the Mediterranean area and Central Europe, and is exposed to a variety of air masses. Sub-micrometer number size distributions, aerosol hygroscopicity at 90% RH, refractory size distribution at 270°C and black carbon mass were continuously measured. Number size distributions and hygroscopic properties indicate that the site is exposed to aged continental air masses, however during daytime it is also affected by upslope winds. The mixing of this transported polluted boundary layer air masses with relatively clean FT air leads to frequent nucleation events around local noon. Night-time size distributions including fine and coarse fractions for each air mass episode have been parameterized by a 3-modal lognormal distribution. Number and volume concentrations in the sub-micrometer modes are strongly affected by the air mass origin, with highest levels in NW-European air masses, versus very clean air in the ''Arctic'' episode. During the dust episode, the coarse mode is clearly enhanced. The observed hygroscopic behavior of the aerosol is consistent with the chemical composition described by Putaud et al. (2004a), but no closure could be made because the hygroscopic properties of the water-soluble organic matter is not known. The data suggest that WSOM is slightly-to-moderately hygroscopic, and that this property may well depend on the air mass origin and history. Although externally mixing is observed in all air masses, the occurrence of ''less'' hygroscopic particles has mostly such a low occurrence rate that the average growth factor distribution mostly appears as a single mode. This is not the case for the dust episode, where the external mixing between less hygroscopic and more hygroscopic particles is very prominent, and indicating clearly the occurrence of a dust accumulation mode, extending down to 50 nm particles, along with an anthropogenic pollution mode. The presented physical measurements finally allow us to provide a partitioning of the sub-µm aerosol in four non-overlapping fractions (soluble + volatile, non-soluble + volatile, refractory + non-BC, BC) which can be roughly associated with separate groups of chemical compounds (ions, organic matter, dust, BC). For what concerns the relative contributions of the fractions, all air masses except the free-tropospheric (FT) and Dust Episodes show a similar composition within the uncertainty of the data. The latter two have a significantly higher refractory fraction, which in the FT air mass is attributed to carbonaceous particles, and in the dust episode to a sub-µm accumulation mode of dust.


2010 ◽  
Vol 3 (5) ◽  
pp. 4313-4354
Author(s):  
A. Roiger ◽  
H. Aufmhoff ◽  
P. Stock ◽  
F. Arnold ◽  
H. Schlager

Abstract. An airborne chemical ionization ion trap mass spectrometer instrument (CI-ITMS) has been developed for tropospheric and stratospheric fast in-situ measurements of PAN (peroxyacetyl nitrate) and PPN (peroxypropionyl nitrate). The first scientific deployment of the FASTPEX instrument (FASTPEX = Fast Measurement of Peroxyacyl nitrates) took place in the Arctic during 18 missions aboard the DLR research aircraft Falcon, within the framework of the POLARCAT-GRACE campaign in the summer of 2008. The FASTPEX instrument is described and characteristic properties of the employed ion trap mass spectrometer are discussed. Atmospheric data obtained at altitudes of up to ~12 km are presented, from the boundary layer to the lowermost stratosphere. Data were sampled with a time resolution of 2 s and a 2σ detection limit of 25 pmol mol−1. An isotopically labelled standard was used for a permanent online calibration. For this reason the accuracy of the PAN measurements is better than ±10% for mixing ratios greater than 200 pmol mol−1. PAN mixing ratios in the summer Arctic troposphere were in the order of a few hundred pmol mol−1 and generally correlated well with CO. In the Arctic boundary layer and lowermost stratosphere smaller PAN mixing ratios were observed due to a combination of missing local sources of PAN precursor gases and efficient removal processes (thermolysis/photolysis). PPN, the second most abundant PAN homologue, was measured simultanously. Observed PPN/PAN ratios range between ~0.03 and 0.3.


1992 ◽  
Vol 97 (D15) ◽  
pp. 16383 ◽  
Author(s):  
R. C. Harriss ◽  
S. C. Wofsy ◽  
D. S. Bartlett ◽  
M. C. Shipham ◽  
D. J. Jacob ◽  
...  

2010 ◽  
Vol 10 (21) ◽  
pp. 10223-10236 ◽  
Author(s):  
J. B. Gilman ◽  
J. F. Burkhart ◽  
B. M. Lerner ◽  
E. J. Williams ◽  
W. C. Kuster ◽  
...  

Abstract. The influence of halogen oxidation on the variabilities of ozone (O3) and volatile organic compounds (VOCs) within the Arctic and sub-Arctic atmospheric boundary layer was investigated using field measurements from multiple campaigns conducted in March and April 2008 as part of the POLARCAT project. For the ship-based measurements, a high degree of correlation (r = 0.98 for 544 data points collected north of 68° N) was observed between the acetylene to benzene ratio, used as a marker for chlorine and bromine oxidation, and O3 signifying the vast influence of halogen oxidation throughout the ice-free regions of the North Atlantic. Concurrent airborne and ground-based measurements in the Alaskan Arctic substantiated this correlation and were used to demonstrate that halogen oxidation influenced O3 variability throughout the Arctic boundary layer during these springtime studies. Measurements aboard the R/V Knorr in the North Atlantic and Arctic Oceans provided a unique view of the transport of O3-poor air masses from the Arctic Basin to latitudes as far south as 52° N. FLEXPART, a Lagrangian transport model, was used to quantitatively determine the exposure of air masses encountered by the ship to first-year ice (FYI), multi-year ice (MYI), and total ICE (FYI+MYI). O3 anti-correlated with the modeled total ICE tracer (r = −0.86) indicating that up to 73% of the O3 variability measured in the Arctic marine boundary layer could be related to sea ice exposure.


2007 ◽  
Vol 7 (5) ◽  
pp. 1451-1469 ◽  
Author(s):  
S. Morin ◽  
J. Savarino ◽  
S. Bekki ◽  
S. Gong ◽  
J. W. Bottenheim

Abstract. We report the first measurements of the oxygen isotope anomaly of atmospheric inorganic nitrate from the Arctic. Nitrate samples and complementary data were collected at Alert, Nunavut, Canada (82°30 ' N, 62°19 ' W) in spring 2004. Covering the polar sunrise period, characterized by the occurrence of severe boundary layer ozone depletion events (ODEs), our data show a significant correlation between the variations of atmospheric ozone (O3) mixing ratios and Δ17O of nitrate (Δ17O(NO−3)). This relationship can be expressed as: Δ17O(NO−3)/‰, =(0.15±0.03)×O3/(nmol mol–1)+(29.7±0.7), with R2=0.70(n=12), for Δ17O(NO−3) ranging between 29 and 35 ‰. We derive mass-balance equations from chemical reactions operating in the Arctic boundary layer, that describe the evolution of Δ17O(NO−3) as a function of the concentrations of reactive species and their isotopic characteristics. Changes in the relative importance of O3, RO2 and BrO in the oxidation of NO during ODEs, and the large isotope anomalies of O3 and BrO, are the driving force for the variability in the measured Δ17O(NO−3) . BrONO2 hydrolysis is found to be a dominant source of nitrate in the Arctic boundary layer, in agreement with recent modeling studies.


2011 ◽  
Vol 11 (8) ◽  
pp. 3949-3979 ◽  
Author(s):  
K. Toyota ◽  
J. C. McConnell ◽  
A. Lupu ◽  
L. Neary ◽  
C. A. McLinden ◽  
...  

Abstract. Episodes of high bromine levels and surface ozone depletion in the springtime Arctic are simulated by an online air-quality model, GEM-AQ, with gas-phase and heterogeneous reactions of inorganic bromine species and a simple scheme of air-snowpack chemical interactions implemented for this study. Snowpack on sea ice is assumed to be the only source of bromine to the atmosphere and to be capable of converting relatively stable bromine species to photolabile Br2 via air-snowpack interactions. A set of sensitivity model runs are performed for April 2001 at a horizontal resolution of approximately 100 km×100 km in the Arctic, to provide insights into the effects of temperature and the age (first-year, FY, versus multi-year, MY) of sea ice on the release of reactive bromine to the atmosphere. The model simulations capture much of the temporal variations in surface ozone mixing ratios as observed at stations in the high Arctic and the synoptic-scale evolution of areas with enhanced BrO column amount ("BrO clouds") as estimated from satellite observations. The simulated "BrO clouds" are in modestly better agreement with the satellite measurements when the FY sea ice is assumed to be more efficient at releasing reactive bromine to the atmosphere than on the MY sea ice. Surface ozone data from coastal stations used in this study are not sufficient to evaluate unambiguously the difference between the FY sea ice and the MY sea ice as a source of bromine. The results strongly suggest that reactive bromine is released ubiquitously from the snow on the sea ice during the Arctic spring while the timing and location of the bromine release are largely controlled by meteorological factors. It appears that a rapid advection and an enhanced turbulent diffusion associated with strong boundary-layer winds drive transport and dispersion of ozone to the near-surface air over the sea ice, increasing the oxidation rate of bromide (Br−) in the surface snow. Also, if indeed the surface snowpack does supply most of the reactive bromine in the Arctic boundary layer, it appears to be capable of releasing reactive bromine at temperatures as high as −10 °C, particularly on the sea ice in the central and eastern Arctic Ocean. Dynamically-induced BrO column variability in the lowermost stratosphere appears to interfere with the use of satellite BrO column measurements for interpreting BrO variability in the lower troposphere but probably not to the extent of totally obscuring "BrO clouds" that originate from the surface snow/ice source of bromine in the high Arctic. A budget analysis of the simulated air-surface exchange of bromine compounds suggests that a "bromine explosion" occurs in the interstitial air of the snowpack and/or is accelerated by heterogeneous reactions on the surface of wind-blown snow in ambient air, both of which are not represented explicitly in our simple model but could have been approximated by a parameter adjustment for the yield of Br2 from the trigger.


2021 ◽  
Author(s):  
Marie-Louise Zeller ◽  
Jannis-Michael Huss ◽  
Lena Pfister ◽  
Karl E. Lapo ◽  
Daniela Littmann ◽  
...  

Abstract. The NY-Ålesund TurbulencE Fiber Optic eXperiment, NYTEFOX, was a field experiment at the Arctic site Ny-Ålesund (11.9° E, 78.9° N) and yielded a unique meteorological data set. These data describe the distribution of heat, airflows, and exchange in the Arctic boundary layer for a period of 14 days from 26 February to 10 March 2020. NYTEFOX is the first field experiment to investigate the heterogeneity of airflow and its transport in temperatures, wind, and kinetic energy in the Arctic environment using the Fiber-Optic Distributed Sensing (FODS) technique for horizontal and vertical observations. FODS air temperature and wind speed were observed at a spatial resolution of 0.127 m and 9 s in time along a horizontal array of 700 m at 1 m height above ground level (agl) and along three 7 m vertical profiles. Ancillary data were collected from three sonic anemometers and an acoustic profiler (miniSodar, SOund Detection And Ranging) yielding turbulent flow statistics and vertical profiles in the lowest 300 m agl, respectively. The observations from this field campaign are publicly available on Zenodo (https://doi.org/10.5281/zenodo.4335461) and supplement the data set operationally collected by the Basic Surface Radiation Network (BSRN) meteorological data set at Ny-Ålesund, Svalbard.


2010 ◽  
Vol 10 (6) ◽  
pp. 15167-15196
Author(s):  
J. R. Spackman ◽  
R. S. Gao ◽  
W. D. Neff ◽  
J. P. Schwarz ◽  
L. A. Watts ◽  
...  

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.


2021 ◽  
Vol 13 (7) ◽  
pp. 3439-3452
Author(s):  
Marie-Louise Zeller ◽  
Jannis-Michael Huss ◽  
Lena Pfister ◽  
Karl E. Lapo ◽  
Daniela Littmann ◽  
...  

Abstract. The NY-Ålesund TurbulencE Fiber Optic eXperiment (NYTEFOX) was a field experiment at the Ny-Ålesund Arctic site (78.9∘ N, 11.9∘ E) and yielded a unique meteorological data set. These data describe the distribution of heat, airflows, and exchange in the Arctic boundary layer for a period of 14 d from 26 February to 10 March 2020. NYTEFOX is the first field experiment to investigate the heterogeneity of airflow and its transport of temperature, wind, and kinetic energy in the Arctic environment using the fiber-optic distributed sensing (FODS) technique for horizontal and vertical observations. FODS air temperature and wind speed were observed at a spatial resolution of 0.127 m and a temporal resolution of 9 s along a 700 m horizontal array at 1 m above ground level (a.g.l.) and along three 7 m vertical profiles. Ancillary data were collected from three sonic anemometers and an acoustic profiler (minisodar; sodar is an acronym for “sound detection and ranging”) yielding turbulent flow statistics and vertical profiles in the lowest 300 m a.g.l., respectively. The observations from this field campaign are publicly available on Zenodo (https://doi.org/10.5281/zenodo.4756836, Huss et al., 2021) and supplement the meteorological data set operationally collected by the Baseline Surface Radiation Network (BSRN) at Ny-Ålesund, Svalbard.


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