Search

Your search keyword '"Ryjkov, Andrei"' showing total 27 results
Start Over Author "Ryjkov, Andrei" Publication Year Range Last 50 years
27 results on '"Ryjkov, Andrei"'

1. The Multi-Compartment Hg Modeling and Analysis Project (MCHgMAP): Mercury modeling to support international environmental policy

Author

Dastoor, Ashu, primary, Angot, Hélène, additional, Bieser, Johannes, additional, Brocza, Flora, additional, Edwards, Brock, additional, Feinberg, Aryeh, additional, Feng, Xinbin, additional, Geyman, Benjamin, additional, Gournia, Charikleia, additional, He, Yipeng, additional, Hedgecock, Ian M., additional, Ilyin, Ilia, additional, Keating, Terry, additional, Kirk, Jane, additional, Lin, Che-Jen, additional, Lehnherr, Igor, additional, Mason, Robert, additional, McLagan, David, additional, Muntean, Marilena, additional, Rafaj, Peter, additional, Roy, Eric M., additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, De Simone, Francesco, additional, Soerensen, Anne L., additional, Steenhuisen, Frits, additional, Travnikov, Oleg, additional, Wang, Shuxiao, additional, Wang, Xun, additional, Wilson, Simon, additional, Wu, Rosa, additional, Wu, Qingru, additional, Zhang, Yanxu, additional, Zhou, Jun, additional, Zhu, Wei, additional, and Zolkos, Scott, additional

Published
2024
Full Text
View/download PDF

2. Arctic mercury cycling

Author

Dastoor, Ashu, Angot, Hélène, Bieser, Johannes, Christensen, Jesper H., Douglas, Thomas A., Heimbürger-Boavida, Lars-Eric, Jiskra, Martin, Mason, Robert P., McLagan, David S., Obrist, Daniel, Outridge, Peter M., Petrova, Mariia V., Ryjkov, Andrei, St. Pierre, Kyra A., Schartup, Amina T., Soerensen, Anne L., Toyota, Kenjiro, Travnikov, Oleg, Wilson, Simon J., and Zdanowicz, Christian

Published
2022
Full Text
View/download PDF

5. Diet and landscape characteristics drive spatial patterns of mercury accumulation in a high-latitude terrestrial carnivore

Author

Peraza, Inés, primary, Chételat, John, additional, Richardson, Murray, additional, Jung, Thomas S., additional, Awan, Malik, additional, Baryluk, Steve, additional, Dastoor, Ashu, additional, Harrower, William, additional, Kukka, Piia M., additional, McClelland, Christine, additional, Mowat, Garth, additional, Pelletier, Nicolas, additional, Rodford, Christine, additional, and Ryjkov, Andrei, additional

Published
2023
Full Text
View/download PDF

8. Modelling the coupled mercury-halogen-ozone cycle in the central Arctic during spring

Author

Ahmed, Shaddy, primary, Thomas, Jennie L., additional, Angot, Hélène, additional, Dommergue, Aurélien, additional, Archer, Stephen D., additional, Bariteau, Ludovic, additional, Beck, Ivo, additional, Benavent, Nuria, additional, Blechschmidt, Anne-Marlene, additional, Blomquist, Byron, additional, Boyer, Matthew, additional, Christensen, Jesper H., additional, Dahlke, Sandro, additional, Dastoor, Ashu, additional, Helmig, Detlev, additional, Howard, Dean, additional, Jacobi, Hans-Werner, additional, Jokinen, Tuija, additional, Lapere, Rémy, additional, Laurila, Tiia, additional, Quéléver, Lauriane L. J., additional, Richter, Andreas, additional, Ryjkov, Andrei, additional, Mahajan, Anoop S., additional, Marelle, Louis, additional, Pfaffhuber, Katrine Aspmo, additional, Posman, Kevin, additional, Rinke, Annette, additional, Saiz-Lopez, Alfonso, additional, Schmale, Julia, additional, Skov, Henrik, additional, Steffen, Alexandra, additional, Stupple, Geoff, additional, Stutz, Jochen, additional, Travnikov, Oleg, additional, and Zilker, Bianca, additional

Published
2023
Full Text
View/download PDF

10. An Improved Representation of Aerosol Mixing State for Air-Quality-Weather Interactions

Author

Stevens, Robin, Ryjkov, Andrei, Majdzadeh, Mahtab, and Dastoor, Ashu

Abstract

We implement a detailed representation of aerosol mixing state in the Global Environmental Multiscale – Modelling Air quality and CHemistry (GEM-MACH) air quality and weather forecast model. Our mixing-state representation includes three categories: one for more hygroscopic aerosol, one for less hygroscopic aerosol with a high black carbon (BC) mass fraction, and one for less hygroscopic aerosol with a low BC mass fraction. The more detailed representation allows us to better resolve two different aspects of aerosol mixing state: differences in hygroscopicity due to aerosol composition and the amount of absorption enhancement of BC due to non-absorbing coatings. Notably, this three-category representation allows us to account for BC thickly coated with primary organic matter, which enhances the absorption of the BC but has a low hygroscopicity. We compare the results of the three-category representation (1L2B, (one hydrophilic, two hydrophobic)) with a simulation that uses two categories, split by hygroscopicity (HYGRO), and a simulation using the original size-resolved internally mixed assumption (SRIM). We perform a case study that is focused on North America during July 2016, when there were intense wildfires over northwestern North America. We find that the more detailed representation of the aerosol hygroscopicity in both 1L2B and HYGRO decreases wet deposition, which increases aerosol concentrations, particularly of less hygroscopic species. The concentration of PM2.5 increases by 23 % on average. We show that these increased aerosol concentrations increase cloud droplet number concentrations and cloud reflectivity in the model, decreasing surface temperatures. Using two categories based on hygroscopicity yields only a modest benefit in resolving the coating thickness on black carbon, however. The 1L2B representation resolves BC with thinner coatings than the HYGRO simulation, resulting in absorption aerosol optical depths that are 3 % less on average, with greater differences over strong anthropogenic source regions. We did not find strong subsequent effects of this decreased absorption on meteorology.

Published
2022

12. Quantification of Spatial and Temporal Trends in Atmospheric Mercury Deposition across Canada over the Past 30 Years

Author

Roberts, Sarah L., primary, Kirk, Jane L., additional, Muir, Derek C. G., additional, Wiklund, Johan A., additional, Evans, Marlene S., additional, Gleason, Amber, additional, Tam, Allison, additional, Drevnick, Paul E., additional, Dastoor, Ashu, additional, Ryjkov, Andrei, additional, Yang, Fan, additional, Wang, Xiaowa, additional, Lawson, Greg, additional, Pilote, Martin, additional, Keating, Jonathan, additional, Barst, Benjamin D., additional, Ahad, Jason M. E., additional, and Cooke, Colin A., additional

Published
2021
Full Text
View/download PDF

15. Spatial variation of mercury bioaccumulation in bats of Canada linked to atmospheric mercury deposition

Author

Chételat, John, primary, Hickey, M. Brian C., additional, Poulain, Alexandre J., additional, Dastoor, Ashu, additional, Ryjkov, Andrei, additional, McAlpine, Donald, additional, Vanderwolf, Karen, additional, Jung, Thomas S., additional, Hale, Lesley, additional, Cooke, Emma L.L., additional, Hobson, Dave, additional, Jonasson, Kristin, additional, Kaupas, Laura, additional, McCarthy, Sara, additional, McClelland, Christine, additional, Morningstar, Derek, additional, Norquay, Kaleigh J.O., additional, Novy, Richard, additional, Player, Delanie, additional, Redford, Tony, additional, Simard, Anouk, additional, Stamler, Samantha, additional, Webber, Quinn M.R., additional, Yumvihoze, Emmanuel, additional, and Zanuttig, Michelle, additional

Published
2018
Full Text
View/download PDF

18. Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

Author

Bieser, Johannes, primary, Slemr, Franz, additional, Ambrose, Jesse, additional, Brenninkmeijer, Carl, additional, Brooks, Steve, additional, Dastoor, Ashu, additional, DeSimone, Francesco, additional, Ebinghaus, Ralf, additional, Gencarelli, Christian N., additional, Geyer, Beate, additional, Gratz, Lynne E., additional, Hedgecock, Ian M., additional, Jaffe, Daniel, additional, Kelley, Paul, additional, Lin, Che-Jen, additional, Jaegle, Lyatt, additional, Matthias, Volker, additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, Song, Shaojie, additional, Travnikov, Oleg, additional, Weigelt, Andreas, additional, Luke, Winston, additional, Ren, Xinrong, additional, Zahn, Andreas, additional, Yang, Xin, additional, Zhu, Yun, additional, and Pirrone, Nicola, additional

Published
2017
Full Text
View/download PDF

19. Multi-model study of mercury dispersion in the atmosphere: atmospheric processes and model evaluation

Author

Travnikov, Oleg, primary, Angot, Hélène, additional, Artaxo, Paulo, additional, Bencardino, Mariantonia, additional, Bieser, Johannes, additional, D'Amore, Francesco, additional, Dastoor, Ashu, additional, De Simone, Francesco, additional, Diéguez, María del Carmen, additional, Dommergue, Aurélien, additional, Ebinghaus, Ralf, additional, Feng, Xin Bin, additional, Gencarelli, Christian N., additional, Hedgecock, Ian M., additional, Magand, Olivier, additional, Martin, Lynwill, additional, Matthias, Volker, additional, Mashyanov, Nikolay, additional, Pirrone, Nicola, additional, Ramachandran, Ramesh, additional, Read, Katie Alana, additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, Sena, Fabrizio, additional, Song, Shaojie, additional, Sprovieri, Francesca, additional, Wip, Dennis, additional, Wängberg, Ingvar, additional, and Yang, Xin, additional

Published
2017
Full Text
View/download PDF

20. Multi-model study of mercury dispersion in the atmosphere: Vertical distribution of mercury species

Author

Bieser, Johannes, primary, Slemr, Franz, additional, Ambrose, Jesse, additional, Brenninkmeijer, Carl, additional, Brooks, Steve, additional, Dastoor, Ashu, additional, DeSimone, Francesco, additional, Ebinghaus, Ralf, additional, Gencarelli, Christian, additional, Geyer, Beate, additional, Gratz, Lynne E., additional, Hedgecock, Ian M., additional, Jaffe, Daniel, additional, Kelley, Paul, additional, Lin, Che-Jen, additional, Matthias, Volker, additional, Ryjkov, Andrei, additional, Selin, Noelle, additional, Song, Shaojie, additional, Travnikov, Oleg, additional, Weigelt, Andreas, additional, Luke, Winston, additional, Ren, Xinrong, additional, Zahn, Andeas, additional, Yang, Xin, additional, Zhu, Yun, additional, and Pirrone, Nicola, additional

Published
2016
Full Text
View/download PDF

21. Supplementary material to "Multi-model study of mercury dispersion in the atmosphere: Vertical distribution of mercury species"

Author

Bieser, Johannes, primary, Slemr, Franz, additional, Ambrose, Jesse, additional, Brenninkmeijer, Carl, additional, Brooks, Steve, additional, Dastoor, Ashu, additional, DeSimone, Francesco, additional, Ebinghaus, Ralf, additional, Gencarelli, Christian, additional, Geyer, Beate, additional, Gratz, Lynne E., additional, Hedgecock, Ian M., additional, Jaffe, Daniel, additional, Kelley, Paul, additional, Lin, Che-Jen, additional, Matthias, Volker, additional, Ryjkov, Andrei, additional, Selin, Noelle, additional, Song, Shaojie, additional, Travnikov, Oleg, additional, Weigelt, Andreas, additional, Luke, Winston, additional, Ren, Xinrong, additional, Zahn, Andeas, additional, Yang, Xin, additional, Zhu, Yun, additional, and Pirrone, Nicola, additional

Published
2016
Full Text
View/download PDF

22. Multi-model study of mercury dispersion in the atmosphere: Atmospheric processes and model evaluation

Author

Travnikov, Oleg, primary, Angot, Hélène, additional, Artaxo, Paulo, additional, Bencardino, Mariantonia, additional, Bieser, Johannes, additional, D’Amore, Francesco, additional, Dastoor, Ashu, additional, De Simone, Francesco, additional, Diéguez, María del Carmen, additional, Dommergue, Aurélien, additional, Ebinghaus, Ralf, additional, Feng, Xin Bin, additional, Gencarelli, Christian N., additional, Hedgecock, Ian M., additional, Magand, Olivier, additional, Martin, Lynwill, additional, Matthias, Volker, additional, Mashyanov, Nikolay, additional, Pirrone, Nicola, additional, Ramachandran, Ramesh, additional, Read, Katie Alana, additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, Sena, Fabrizio, additional, Song, Shaojie, additional, Sprovieri, Francesca, additional, Wip, Dennis, additional, Wängberg, Ingvar, additional, and Yang, Xin, additional

Published
2016
Full Text
View/download PDF

23. Supplementary material to "Multi-model study of mercury dispersion in the atmosphere: Atmospheric processes and model evaluation"

Author

Travnikov, Oleg, primary, Angot, Hélène, additional, Artaxo, Paulo, additional, Bencardino, Mariantonia, additional, Bieser, Johannes, additional, D’Amore, Francesco, additional, Dastoor, Ashu, additional, De Simone, Francesco, additional, Diéguez, María del Carmen, additional, Dommergue, Aurélien, additional, Ebinghaus, Ralf, additional, Feng, Xin Bin, additional, Gencarelli, Christian N., additional, Hedgecock, Ian M., additional, Magand, Olivier, additional, Martin, Lynwill, additional, Matthias, Volker, additional, Mashyanov, Nikolay, additional, Pirrone, Nicola, additional, Ramachandran, Ramesh, additional, Read, Katie Alana, additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, Sena, Fabrizio, additional, Song, Shaojie, additional, Sprovieri, Francesca, additional, Wip, Dennis, additional, Wängberg, Ingvar, additional, and Yang, Xin, additional

Published
2016
Full Text
View/download PDF

24. Chemical cycling and deposition of atmospheric mercury in polar regions: review of recent measurements and comparison with models

Author

Angot, Hélène, primary, Dastoor, Ashu, additional, De Simone, Francesco, additional, Gårdfeldt, Katarina, additional, Gencarelli, Christian N., additional, Hedgecock, Ian M., additional, Langer, Sarka, additional, Magand, Olivier, additional, Mastromonaco, Michelle N., additional, Nordstrøm, Claus, additional, Pfaffhuber, Katrine A., additional, Pirrone, Nicola, additional, Ryjkov, Andrei, additional, Selin, Noelle E., additional, Skov, Henrik, additional, Song, Shaojie, additional, Sprovieri, Francesca, additional, Steffen, Alexandra, additional, Toyota, Kenjiro, additional, Travnikov, Oleg, additional, Yang, Xin, additional, and Dommergue, Aurélien, additional

Published
2016
Full Text
View/download PDF

25. How important is biomass burning in Canada to mercury contamination?

Author

Fraser, Annemarie, Dastoor, Ashu, and Ryjkov, Andrei

Abstract

Wildfire frequency has increased in past four decades in Canada, and is expected to increase in future as a result of climate change (Wotton et al., 2010). Mercury (Hg) emissions from biomass burning are known to be significant; however, the impact of biomass burning on air concentration and deposition fluxes in Canada has not been previously quantified. We use estimates of burned biomass from FINN (Fire Inventory from NCAR) and vegetation-specific Emission Factors (EFs) of mercury to investigate the spatiotemporal variability of Hg emissions in Canada. We use Environment and Climate Change Canada's GEM-MACH-Hg (Global Environmental Multi-scale, Modelling Air quality and Chemistry model, mercury version) to quantify the impact of biomass burning in Canada on spatiotemporal variability of air concentrations and deposition fluxes of mercury in Canada. We use North American gaseous elemental mercury (GEM) observations (2010-2015), GEM-MACH-Hg, and an inversion technique to optimize the emission factors for GEM for five vegetation types represented in North American fires to constrain the biomass burning impacts of mercury. We use three biomass burning Hg emissions scenarios in Canada to conduct three sets of model simulations for 2010-2015: two scenarios where Hg is emitted only as GEM using literature or optimized EFs, and a third scenario where Hg is emitted as GEM using literature EFs and particle bound mercury (PBM) emitted using the average GEM/PBM ratio from lab measurements. The three biomass burning emission scenarios represent the range of possible values for the impacts of Hg emissions from biomass burning in Canada on Hg concentration and deposition. We find total biomass burning Hg emissions to be highly variable from year to year, and estimate average 2010-2015 total atmospheric biomass burning emissions of Hg in Canada to be between 6-14 t during the biomass burning season (i.e., from May to September), which is 3-7 times the mercury emission from anthropogenic sources in Canada for this period. On average, 65 % of the emissions occur in the provinces west of Ontario. We find that while emissions from biomass burning have a small impact on surface air concentrations of GEM averaged over individual provinces/territories, the impact at individual sites can be as high as 95 % during burning events. We estimate average annual mercury deposition from biomass burning in Canada to be between 0.3-2.8 t, compared to 0.14 t of mercury deposition from anthropogenic sources during the biomass burning season in Canada. Compared to the biomass burning emissions, the relative impact of fires on mercury deposition is shifted eastward, with on average 54 % of the deposition occurring in provinces west of Ontario. While the relative contribution of Canadian biomass burning to the total mercury deposition over each province/territory is no more than 9 % between 2010-2015, the local contribution in some locations (including areas downwind of biomass burning) can be as high as 80 % (e.g. northwest of Great Slave Lake in 2014) from May-September. We find that northern Alberta and Saskatchewan, central British Columbia, and the area around Great Slave Lake in the Northwest Territories are at greater risk of mercury contamination from biomass burning. GEM is considered to be the dominant mercury species emitted from biomass burning; however, there remains an uncertainty in the speciation of mercury released from biomass burning. We find that the impact of biomass burning emissions on mercury deposition is significantly affected by the uncertainty in speciation of emitted mercury because PBM is more readily deposited closer to the emission sources than GEM; an addition of ~ 18 % of mercury emission from biomass burning in the form of PBM in the model increases the 6 year average deposition by ~ 4 times. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

27. Multi-model study of mercury dispersion in the atmosphere: Vertical distribution of mercury species.

Author

Bieser, Johannes, Slemr, Franz, Ambrose, Jesse, Brenninkmeijer, Carl, Brooks, Steve, Dastoor, Ashu, DeSimone, Francesco, Ebinghaus, Ralf, Gencarelli, Christian, Geyer, Beate, Gratz, Lynne E., Hedgecock, Ian M., Jaffe, Daniel, Kelley, Paul, Che-Jen Lin, Matthias, Volker, Ryjkov, Andrei, Selin, Noelle, Shaojie Song, and Travnikov, Oleg

Abstract

Atmospheric chemistry and transport of mercury play a key role in the global mercury cycle. However, there are still considerable knowledge gaps concerning the fate of mercury in the atmosphere. This is the second part of a model inter-comparison study investigating the impact of atmospheric chemistry and emissions on mercury in the atmosphere. While the first study focused on ground based observations of mercury concentration and deposition, here we investigate the vertical distribution and speciation of mercury from the planetary boundary layer to the lower stratosphere. So far, there have been few model studies investigating the vertical distribution of mercury, mostly focusing on single aircraft campaigns. Here, we present a first comprehensive analysis based on various aircraft observations in Europe, North America, and on inter-continental flights. The investigated models proved to be able to reproduce the distribution of total and elemental mercury concentrations in the troposphere including inter-hemispheric trends. One key aspect of the study is the investigation of mercury oxidation in the troposphere. We found that different chemistry schemes were better at reproducing observed oxidized mercury (RM) patterns depending on altitude. High RM concentrations in the upper troposphere could be reproduced with oxidation by bromine while elevated concentrations in the lower troposphere were better reproduced by OH and ozone chemistry. However, the results were not always conclusive as the physical and chemical parametrizations in the chemistry transport models also proved to have a substantial impact on model results. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results