scholarly journals Final Progress Report for Collaborative Research: Aging of Black Carbon during Atmospheric Transport: Understanding Results from the DOE’s 2010 CARES and 2012 ClearfLo Campaigns

2016 ◽  
Author(s):  
Claudio Mazzoleni ◽  
R. Subramanian
Keyword(s):  
Black Carbon ◽  
Collaborative Research ◽  
Atmospheric Transport ◽  
Progress Report

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 Black carbon over Mexico: the effect of atmospheric transport on mixing state, mass absorption cross-section, and BC/CO ratios

2010 ◽  
Vol 10 (1) ◽  
pp. 219-237 ◽  
Author(s):  
R. Subramanian ◽  
G. L. Kok ◽  
D. Baumgardner ◽  
A. Clarke ◽  
Y. Shinozuka ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mexico City ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Atmospheric Transport ◽  
Absorption Cross ◽  
Air Masses ◽  
Wet Scavenging ◽  
The City ◽  
Absorption Photometer

Abstract. A single particle soot photometer (SP2) was operated on the NCAR C-130 during the MIRAGE campaign (part of MILAGRO), sampling black carbon (BC) over Mexico. The highest BC concentrations were measured over Mexico City (sometimes as much as 2 μg/m3) and over hill-fires to the south of the city. The age of plumes outside of Mexico City was determined using a combination of HYSPLIT trajectories, WRF-FLEXPART modeling and CMET balloon tracks. As expected, older, diluted air masses had lower BC concentrations. A comparison of carbon monoxide (CO) and BC suggests a CO background of around 65 ppbv, and a background-corrected BC/COnet ratio of 2.89±0.89 (ng/m3-STP)/ppbv (average ± standard deviation). This ratio is similar for fresh emissions over Mexico City, as well as for aged airmasses. Comparison of light absorption measured with a particle soot absorption photometer (PSAP) and the SP2 BC suggests a BC mass-normalized absorption cross-section (MAC) of 10.9±2.1 m2/g at 660 nm (or 13.1 m2/g @ 550 nm, assuming MAC is inversely dependent on wavelength). This appears independent of aging and similar to the expected absorption cross-section for aged BC, but values, particularly in fresh emissions, could be biased high due to instrument artifacts. SP2-derived BC coating indicators show a prominent thinly-coated BC mode over the Mexico City Metropolitan Area (MCMA), while older air masses show both thinly-coated and thickly-coated BC. Some 2-day-old plumes do not show a prominent thickly-coated BC mode, possibly due to preferential wet scavenging of the likely-hydrophilic thickly-coated BC.

scholarly journals Influx of African biomass burning aerosol during the Amazonian dry season through layered transatlantic transport of black carbon-rich smoke

2019 ◽  
Author(s):  
Bruna A. Holanda ◽  
Mira L. Pöhlker ◽  
Jorge Saturno ◽  
Matthias Sörgel ◽  
Jeannine Ditas ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Amazon Basin ◽  
Hydrological Cycle ◽  
Atmospheric Transport ◽  
Cloud Condensation Nuclei ◽  
Single Scattering ◽  
Brazilian Coast ◽  
Strong Impact ◽  
The North

Abstract. Black carbon (BC) aerosols are influencing the Earth’s atmosphere and climate, but their microphysical properties, spatiotemporal distribution and long-range transport are not well constrained. This study analyzes the transatlantic transport of BC-rich African biomass burning (BB) pollution into the Amazon Basin, based on airborne observations of aerosol particles and trace gases in and off the Brazilian coast during the ACRIDICON-CHUVA campaign in September 2014, combining in-situ measurements on the research aircraft HALO with satellite remote-sensing and numerical model results. During flight AC19 over land and ocean at the Brazilian coastline in the northeast of the Amazon Basin, we observed a BC-rich atmospheric layer at ~ 3.5 km altitude with a vertical extension of ~ 0.3 km. Backward trajectory analyses suggest that fires in African grasslands, savannas, and shrublands were the main source of this pollution layer, and that the observed BB smoke had undergone more than 10 days of atmospheric transport and aging. The BC mass concentrations in the layer ranged from 0.5 to 2 μg m−3, and the BC particle number fraction of ~ 40 % was about 8 times higher than observed in a fresh Amazonian BB plume, representing the highest value ever observed in the region. Upon entering the Amazon Basin, the layer started to broaden and to subside, due to convective mixing and entrainment of the BB aerosol into the boundary layer. Satellite observations show that the transatlantic transport of pollution layers is a frequently occurring process, seasonally peaking in August/September. By analyzing the aircraft observations within the broader context of the long-term data from the Amazon Tall Tower Observatory (ATTO), we found that the transatlantic transport of African BB smoke layers has a strong impact on the north-central Amazonian aerosol population during the BB-influenced season (July to November). Specifically, the early BB season in this part of the Amazon appears to be dominated by African smoke, whereas the later BB season appears to be dominated by South American fires. This dichotomy is reflected in pronounced changes of aerosol optical properties such as the single scattering albedo (increasing from 0.85 in August to 0.90 in November) and the BC-to-CO enhancement ratio (decreasing from 7.4 to 4.4 ng m−3 ppb−1). Our results suggest that, despite the high amount of BC particles, the African BB aerosol act as efficient cloud condensation nuclei (CCN) with potentially important implications for aerosol-cloud interactions and the hydrological cycle in the Amazon Basin.

scholarly journals Long-term trends of black carbon and sulphate aerosol in the Arctic: changes in atmospheric transport and source region emissions

2010 ◽  
Vol 10 (5) ◽  
pp. 12133-12184 ◽  
Author(s):  
D. Hirdman ◽  
J. F. Burkhart ◽  
H. Sodemann ◽  
S. Eckhardt ◽  
A. Jefferson ◽  
...  
Keyword(s):  
Black Carbon ◽  
Atmospheric Circulation ◽  
Atmospheric Transport ◽  
Particle Dispersion ◽  
Downward Trend ◽  
The Arctic ◽  
Northern Eurasia ◽  
Source Regions ◽  
Long Term Trends

Abstract. As a part of the IPY project POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport) and building on previous work (Hirdman et al., 2010), this paper studies the long-term trends of both atmospheric transport as well as equivalent black carbon (EBC) and sulphate for the three Arctic stations Alert, Barrow and Zeppelin. We find a general downward trend in the measured EBC concentrations at all three stations, with a decrease of −2.1±0.4 ng m−3 yr−1 (for the years 1989–2008) and −1.4±0.8 ng m−3 yr−1 (2002–2009) at Alert and Zeppelin respectively. The decrease at Barrow is, however, not statistically significant. The measured sulphate concentrations show a decreasing trend at Alert and Zeppelin of −15±3 ng m−3 yr−1 (1985–2006) and −1.3±1.2 ng m−3 yr−1 (1990–2008) respectively, while the trend at Barrow is unclear. To reveal the influence of different source regions on these trends, we used a cluster analysis of the output of the Lagrangian particle dispersion model FLEXPART run backward in time from the measurement stations. We have investigated to what extent variations in the atmospheric circulation, expressed as variations in the frequencies of the transport from four source regions with different emission rates, can explain the long-term trends in EBC and sulphate measured at these stations. We find that the long-term trend in the atmospheric circulation can only explain a minor fraction of the overall downward trend seen in the measurements of EBC (0.3–7.2%) and sulphate (0.3–5.3%) at the Arctic stations. The changes in emissions are dominant in explaining the trends. We find that the highest EBC and sulphate concentrations are associated with transport from Northern Eurasia and decreasing emissions in this region drive the downward trends. Northern Eurasia (cluster: NE, WNE and ENE) is the dominant emission source at all Arctic stations for both EBC and sulphate during most seasons. In wintertime, there are indications that the EBC emissions from the eastern parts of Northern Eurasia (ENE cluster) have increased over the last decade.

scholarly journals A First-year Progress Report on "Collaborative Research Using Low-cost Desktop Learning Modules to Educate Diverse Undergraduate Communities in Engineering"

2020 ◽  
Author(s):  
Katelyn Dahlke ◽  
Kitana Kaiphanliam ◽  
Bernard Van Wie ◽  
David Thiessen ◽  
Prashanta Dutta ◽  
...  
Keyword(s):  
Collaborative Research ◽  
Low Cost ◽  
Progress Report ◽  
First Year ◽  
Learning Modules

Qualitative methods II

2016 ◽  
Vol 41 (6) ◽  
pp. 823-831 ◽  
Author(s):  
Robyn Dowling ◽  
Kate Lloyd ◽  
Sandra Suchet-Pearson
Keyword(s):  
Qualitative Methods ◽  
Collaborative Research ◽  
Human Geography ◽  
Progress Report ◽  
Power Relationships ◽  
Human Research ◽  
The World ◽  
Growing Body ◽  
Research Relationships ◽  
Methodological Approaches

Various identified ‘turns’ in human geography, such as relational, non-representational, material and performative, urge and enable geographers to rethink complex people-nature relationships as contingent and layered processes, and the world as projects of human and more-than-human inhabitation. This shift challenges researchers to do geography differently, or in other words, invites alterations in thinking and methods. This progress report focuses on how qualitative researchers in human geography are grappling with the challenge of more-than-human research methodologies. We chart analyses of more-than-human worlds that are reliant on conventional methodological approaches, as well as more innovative methodological approaches which extend more-than-human understandings whilst recognizing their own limits. The report finally considers a small but growing body of work that takes an additional methodological step in developing human–more-than-human collaborative research relationships that are actively engaging with power relationships by reconsidering the author-ity of their research. We conclude that although the more-than-human ‘turn’ is being thoroughly debated and engaged with in theory, the implications of this have not carried through to the same extent in terms of praxis.

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