scholarly journals Accumulation-mode aerosol number concentrations in the Arctic during the ARCTAS aircraft campaign: Long-range transport of polluted and clean air from the Asian continent

2011 ◽  
Vol 116 (D20) ◽  
Author(s):  
H. Matsui ◽  
Y. Kondo ◽  
N. Moteki ◽  
N. Takegawa ◽  
L. K. Sahu ◽  
...  
Keyword(s):  
Long Range ◽  
The Arctic ◽  
Long Range Transport ◽  
Asian Continent ◽  
Accumulation Mode ◽  
Range Transport ◽  
Clean Air

scholarly journals New insights into aerosol and climate in the Arctic

2018 ◽  
Author(s):  
Jonathan P. D. Abbatt ◽  
W. Richard Leaitch ◽  
Amir A. Aliabadi ◽  
Alan K. Bertram ◽  
Jean-Pierre Blanchet ◽  
...  
Keyword(s):  
Long Range ◽  
Mineral Dust ◽  
Sea Surface ◽  
The Arctic ◽  
Long Range Transport ◽  
Surface Microlayer ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Range Transport ◽  
Warming World

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013 . (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water and the overlying atmosphere in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source. (2) Evidence was found of widespread particle nucleation and growth in the marine boundary layer in the CAA in the summertime. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from sea bird colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic material (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow.

Dirty sea ice drives higher Mn concentrations in the Canada Basin

2021 ◽  
Author(s):  
Birgit Rogalla ◽  
Susan E. Allen ◽  
Manuel Colombo ◽  
Paul G. Myers ◽  
Kristin J. Orians
Keyword(s):  
Sea Ice ◽  
Long Range ◽  
Sediment Resuspension ◽  
Three Dimensional ◽  
Arctic Sea Ice ◽  
Canada Basin ◽  
The Arctic ◽  
Long Range Transport ◽  
Basin Surface ◽  
Range Transport

<p>The rapidly changing conditions of the Arctic sea ice system have cascading impacts on the biogeochemical cycles of the ocean. Sea ice transports sediments, nutrients, trace metals, pollutants, and gases from the extensive continental shelves into the more isolated central basins. However, it is difficult to assess the net contribution of this supply mechanism on nutrients in the surface ocean. In this study, we used Manganese (Mn), a micronutrient and tracer which can integrate source fluctuations in space and time, to understand the net impact of the long range transport of sea ice for Mn.</p><p>We developed a three-dimensional dissolved Mn model within a subdomain of the 1/12 degree Arctic and Northern Hemispheric Atlantic (ANHA12) configuration of NEMO centred on the Canadian Arctic Archipelago, and evaluated this model with in situ observations from the 2015 Canadian GEOTRACES cruises. The Mn model incorporates parameterizations for the contributions from river discharge, sediment resuspension, atmospheric deposition of aerosols directly to the ocean and via melt from sea ice, release of sediment from sea ice, and reversible scavenging, while the NEMO-TOP engine takes care of the advection and diffusion of the tracers. </p><p>Simulations with this model from 2002 to 2019 indicate that the majority of external Mn contributed annually to the Canada Basin surface is released by sediment from sea ice, much of which originates from the Siberian shelves. Reduced sea ice longevity in the Siberian shelf regions has been postulated to result in the disruption of the long range transport of sea ice by the transpolar drift. This reduced sea ice supply has the potential to decrease the Canada Basin Mn surface maximum and downstream Mn supply, with implications for other nutrients (such as Fe) contained in ice-rafted sediments as well. These results demonstrate some of the many changes to the biogeochemical supply mechanisms expected in the near-future in the Arctic Ocean and the subpolar seas.</p>

scholarly journals Overview paper: New insights into aerosol and climate in the Arctic

2019 ◽  
Vol 19 (4) ◽  
pp. 2527-2560 ◽  
Author(s):  
Jonathan P. D. Abbatt ◽  
W. Richard Leaitch ◽  
Amir A. Aliabadi ◽  
Allan K. Bertram ◽  
Jean-Pierre Blanchet ◽  
...  
Keyword(s):  
Long Range ◽  
Mineral Dust ◽  
Sea Surface ◽  
The Arctic ◽  
Long Range Transport ◽  
Surface Microlayer ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Range Transport ◽  
Warming World

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summertime dimethyl sulfide (DMS) levels were identified in ocean water (up to 75 nM) and the overlying atmosphere (up to 1 ppbv) in the Canadian Arctic Archipelago (CAA). Furthermore, melt ponds, which are widely prevalent, were identified as an important DMS source (with DMS concentrations of up to 6 nM and a potential contribution to atmospheric DMS of 20 % in the study area). (2) Evidence of widespread particle nucleation and growth in the marine boundary layer was found in the CAA in the summertime, with these events observed on 41 % of days in a 2016 cruise. As well, at Alert, Nunavut, particles that are newly formed and grown under conditions of minimal anthropogenic influence during the months of July and August are estimated to contribute 20 % to 80 % of the 30–50 nm particle number density. DMS-oxidation-driven nucleation is facilitated by the presence of atmospheric ammonia arising from seabird-colony emissions, and potentially also from coastal regions, tundra, and biomass burning. Via accumulation of secondary organic aerosol (SOA), a significant fraction of the new particles grow to sizes that are active in cloud droplet formation. Although the gaseous precursors to Arctic marine SOA remain poorly defined, the measured levels of common continental SOA precursors (isoprene and monoterpenes) were low, whereas elevated mixing ratios of oxygenated volatile organic compounds (OVOCs) were inferred to arise via processes involving the sea surface microlayer. (3) The variability in the vertical distribution of black carbon (BC) under both springtime Arctic haze and more pristine summertime aerosol conditions was observed. Measured particle size distributions and mixing states were used to constrain, for the first time, calculations of aerosol–climate interactions under Arctic conditions. Aircraft- and ground-based measurements were used to better establish the BC source regions that supply the Arctic via long-range transport mechanisms, with evidence for a dominant springtime contribution from eastern and southern Asia to the middle troposphere, and a major contribution from northern Asia to the surface. (4) Measurements of ice nucleating particles (INPs) in the Arctic indicate that a major source of these particles is mineral dust, likely derived from local sources in the summer and long-range transport in the spring. In addition, INPs are abundant in the sea surface microlayer in the Arctic, and possibly play a role in ice nucleation in the atmosphere when mineral dust concentrations are low. (5) Amongst multiple aerosol components, BC was observed to have the smallest effective deposition velocities to high Arctic snow (0.03 cm s−1).

scholarly journals Tagged tracer simulations of black carbon in the Arctic: Transport, source contributions, and budget

2017 ◽  
Author(s):  
Kohei Ikeda ◽  
Hiroshi Tanimoto ◽  
Takafumi Sugita ◽  
Hideharu Akiyoshi ◽  
Yugo Kanaya ◽  
...  
Keyword(s):  
East Asia ◽  
Black Carbon ◽  
Long Range ◽  
Biomass Burning ◽  
East Asian ◽  
The Arctic ◽  
Long Range Transport ◽  
Middle Troposphere ◽  
Source Contributions ◽  
Range Transport

Abstract. We implemented a tagged tracer method of black carbon (BC) into a global chemistry-transport model GEOS-Chem, examined the pathways and efficiency of long-range transport from a variety of anthropogenic and biomass burning emission sources to the Arctic, and quantified the source contributions of individual emissions. Firstly, we evaluated the simulated BC by comparing it with observations at the Arctic sites and found that the simulated seasonal variations were improved by implementing an aging parameterization and reducing the wet scavenging rate by ice clouds. For tagging BC, we added BC tracers distinguished by source types (anthropogenic and biomass burning) and regions; the global domain was divided into 16 and 27 regions for anthropogenic and biomass burning emissions, respectively. Our simulations showed that BC emitted from Europe and Russia was transported to the Arctic mainly in the lower troposphere during winter and spring. In particular, BC transported from Russia was widely spread over the Arctic in winter and spring, leading to a dominant contribution of 62 % to the Arctic BC near the surface as the annual mean. In contrast, BC emitted from East Asia was found to be transported in the middle troposphere into the Arctic mainly over the Okhotsk Sea and East Siberia during winter and spring. We identified an important window area, which allowed a strong incoming of East Asian BC to the Arctic (130°–180° E and 3–8 km altitude at 66° N). The model demonstrated that the contribution from East Asia to the Arctic had a maximum at about 5 km altitude due to uplifting during the long-range transport in early spring. The efficiency of BC transport from East Asia to the Arctic was smaller than that from other large source regions such as Europe, Russia and North America. However, the East Asian contribution was most important for BC in the middle troposphere (41 %) and BC burden over the Arctic (27 %) because of the large emissions from this region. These results suggested that the main sources of the Arctic BC differed with altitude. The contribution of all the anthropogenic sources to Arctic BC concentrations near the surface was dominant (90 %) on an annual basis. The contributions of biomass burning in boreal regions (Siberia, Alaska and Canada) to the annual total BC deposition onto the Arctic were estimated to be 12–15 %, which became the maximum during summer.

scholarly journals On the origin of the occasional spring nitrate peak in Greenland snow

2014 ◽  
Vol 14 (24) ◽  
pp. 13361-13376 ◽  
Author(s):  
L. Geng ◽  
J. Cole-Dai ◽  
B. Alexander ◽  
J. Erbland ◽  
J. Savarino ◽  
...  
Keyword(s):  
Long Range ◽  
Column Density ◽  
Nitrate Concentration ◽  
Ice Core ◽  
The Arctic ◽  
Long Range Transport ◽  
Pollution Transport ◽  
Spring Peak ◽  
Nitrate Production ◽  
Range Transport

Abstract. Ice core nitrate concentrations peak in the summer in both Greenland and Antarctica. Two nitrate concentration peaks in one annual layer have been observed some years in ice cores in Greenland from samples dating post-1900, with the additional nitrate peak occurring in the spring. The origin of the spring nitrate peak was hypothesized to be pollution transport from the mid-latitudes in the industrial era. We performed a case study on the origin of a spring nitrate peak in 2005 measured from a snowpit at Summit, Greenland, covering 3 years of snow accumulation. The effect of long-range transport of nitrate on this spring peak was excluded by using sulfate as a pollution tracer. The isotopic composition of nitrate (δ15N, δ18O and Δ17O) combined with photochemical calculations suggest that the occurrence of this spring peak is linked to a significantly weakened stratospheric ozone (O3) layer. The weakened O3 layer resulted in elevated UVB (ultraviolet-B) radiation on the snow surface, where the production of OH and NOx from the photolysis of their precursors was enhanced. Elevated NOx and OH concentrations resulted in enhanced nitrate production mainly through the NO2 + OH formation pathway, as indicated by decreases in δ18O and Δ17O of nitrate associated with the spring peak. We further examined the nitrate concentration record from a shallow ice core covering the period from 1772 to 2006 and found 19 years with double nitrate peaks after the 1950s. Out of these 19 years, 14 of the secondary nitrate peaks were accompanied by sulfate peaks, suggesting long-range transport of nitrate as their source. In the other 5 years, low springtime O3 column density was observed, suggesting enhanced local production of nitrate as their source. The results suggest that, in addition to direct transport of nitrate from polluted regions, enhanced local photochemistry can also lead to a spring nitrate peak. The enhanced local photochemistry is probably associated with the interannual variability of O3 column density in the Arctic, which leads to elevated surface UV radiation in some years. In this scenario, enhanced photochemistry caused increased local nitrate production under the condition of elevated local NOx abundance in the industrial era.

scholarly journals Long range transport of mercury to the Arctic and across Canada

2010 ◽  
Vol 10 (2) ◽  
pp. 4673-4717 ◽  
Author(s):  
D. Durnford ◽  
A. Dastoor ◽  
D. Figueras-Nieto ◽  
A. Ryjkov
Keyword(s):  
North America ◽  
Long Range ◽  
Transport Model ◽  
Extensive Study ◽  
Atmospheric Mercury ◽  
The Arctic ◽  
Long Range Transport ◽  
Chemical Transport Model ◽  
Transport Pathways ◽  
Range Transport

Abstract. This study is the most extensive study to date on the transport of mercury to the Arctic. Moreover, it is the first such study to use a fully-coupled, online chemical transport model, Environment Canada's Global/Regional Atmospheric Heavy Metals model (GRAHM), where the meteorology and mercury processes are fully integrated. It is also the only study to date on the transport of mercury across Canada. We determined source attribution from Asia, North America, Russia and Europe at six arctic verification stations, as well as three subarctic and eight midlatitude Canadian stations. We have found that Asia, despite having transport efficiencies that were almost always lower than those of North America and often lower than those of Russia, was the dominant source of gaseous atmospheric mercury at all verification stations: it contributed the most mercury (29–37% at all stations, seasons and levels considered), its concentrations frequently explained nearly 100% of the variability in the concentrations produced by the simulation performed with full global emissions, particularly in the absence of local sources, and it generated the most long range transport (LRT) events, causing 43%, 67% and 75% of the events at the arctic, subarctic and midlatitude stations, respectively. For the Arctic, Russian transport efficiencies tended to be the strongest, as expected, while European and Asian efficiencies were lower and higher, respectively, than those found in the literature. This disagreement is likely produced by mercury's long lifetime relative to that of other pollutants. The accepted springtime preference for the trans-Pacific transport of Asian pollution was evident only in the midlatitude group of stations, being masked in the arctic and subarctic groups by the occurrence of atmospheric mercury depletion events. Some neighbouring arctic stations recorded dissimilar numbers of LRT events; despite their proximity, the behaviour of mercury at these stations was governed by different dynamics and transport pathways. The column burden of GEM in the lowest 5 km of the Northern Hemisphere was largest in summer from Asia, North America and Russia, but in winter from Europe. In the vertical, transport of mercury from all source regions occurred principally in the mid-troposphere.

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