144 results on '"Denjean, Cyrielle"'
Search Results
2. Aerosol-Cloud Interactions and Impact on Regional Climate
- Author
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Nabat, Pierre, Kanji, Zamin A., Mallet, Marc, Denjean, Cyrielle, Solmon, Fabien, Dulac, François, editor, Sauvage, Stéphane, editor, and Hamonou, Eric, editor
- Published
- 2022
- Full Text
- View/download PDF
3. Aerosol Hygroscopicity
- Author
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Denjean, Cyrielle, Dulac, François, editor, Sauvage, Stéphane, editor, and Hamonou, Eric, editor
- Published
- 2022
- Full Text
- View/download PDF
4. Aerosol Optical Properties
- Author
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Mallet, Marc, Chazette, Patrick, Dulac, François, Formenti, Paola, Di Biagio, Claudia, Denjean, Cyrielle, Chiapello, Isabelle, Dulac, François, editor, Sauvage, Stéphane, editor, and Hamonou, Eric, editor
- Published
- 2022
- Full Text
- View/download PDF
5. NO3 reactivity during a summer period in a temperate forest below and above the canopy
- Author
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Dewald, Patrick, primary, Seubert, Tobias, additional, Andersen, Simone T., additional, Türk, Gunther N. T. E., additional, Schuladen, Jan, additional, McGillen, Max R., additional, Denjean, Cyrielle, additional, Etienne, Jean-Claude, additional, Garrouste, Olivier, additional, Jamar, Marina, additional, Harb, Sergio, additional, Cirtog, Manuela, additional, Michoud, Vincent, additional, Cazaunau, Mathieu, additional, Bergé, Antonin, additional, Cantrell, Christopher, additional, Dusanter, Sebastien, additional, Picquet-Varrault, Bénédicte, additional, Kukui, Alexandre, additional, Xue, Chaoyang, additional, Mellouki, Abdelwahid, additional, Lelieveld, Jos, additional, and Crowley, John N., additional
- Published
- 2024
- Full Text
- View/download PDF
6. Supplementary material to "NO3 reactivity during a summer period in a temperate forest below and above the canopy"
- Author
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Dewald, Patrick, primary, Seubert, Tobias, additional, Andersen, Simone T., additional, Türk, Gunther N. T. E., additional, Schuladen, Jan, additional, McGillen, Max R., additional, Denjean, Cyrielle, additional, Etienne, Jean-Claude, additional, Garrouste, Olivier, additional, Jamar, Marina, additional, Harb, Sergio, additional, Cirtog, Manuela, additional, Michoud, Vincent, additional, Cazaunau, Mathieu, additional, Bergé, Antonin, additional, Cantrell, Christopher, additional, Dusanter, Sebastien, additional, Picquet-Varrault, Bénédicte, additional, Kukui, Alexandre, additional, Xue, Chaoyang, additional, Mellouki, Abdelwahid, additional, Lelieveld, Jos, additional, and Crowley, John N., additional
- Published
- 2024
- Full Text
- View/download PDF
7. NO3 reactivity during a summer period in a temperate forest below and above the canopy.
- Author
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Dewald, Patrick, Seubert, Tobias, Andersen, Simone T., Türk, Gunther N. T. E., Schuladen, Jan, McGillen, Max R., Denjean, Cyrielle, Etienne, Jean-Claude, Garrouste, Olivier, Jamar, Marina, Harb, Sergio, Cirtog, Manuela, Michoud, Vincent, Cazaunau, Mathieu, Bergé, Antonin, Cantrell, Christopher, Dusanter, Sebastien, Picquet-Varrault, Bénédicte, Kukui, Alexandre, and Xue, Chaoyang
- Subjects
ATMOSPHERIC chemistry ,TEMPERATE forests ,TEMPERATURE inversions ,HYDROXYL group ,NITRIC oxide - Abstract
We present direct measurements of biogenic volatile organic compound (BVOC)-induced nitrate radical (NO3) reactivity (kVOC) through the diel cycle in the suburban, temperate forest of Rambouillet near Paris (France). The data were obtained in a 6-week summer period in 2022 as part of the Atmospheric ChemistRy Of the Suburban foreSt (ACROSS) campaign. kVOC was measured in a small (700 m2) clearing mainly at a height of 5.5 m above ground level but also at 40 m (for 5 d and nights). At nighttime, mean values (and 25th–75th percentile ranges) of knightVOC(5.5m) = (0.24-0.06+0.32) s-1 and knightVOC(40m) = (0.016-0.007+0.018) s-1 indicate a significant vertical gradient and low NO3 reactivity above the canopy, whereas knightVOC (5.5 m) showed peak values of up to 2 s-1 close to the ground. The strong vertical gradient in NO3 reactivity could be confirmed by measurements between 0 and 24 m on one particular night characterized by a strong temperature inversion and is a result of the decoupling of air masses aloft from the ground- and canopy-level sources of BVOCs (and nitric oxide, NO). No strong vertical gradient was observed in the mean daytime NO3 reactivity, with kdayVOC(5.5m) = (0.12±0.04) s-1 for the entire campaign and kdayVOC(40m) = (0.07±0.02) s-1 during the 5 d period. Within the clearing, the fractional contribution of VOCs to the total NO3 loss rate coefficient (ktot , determined by photolysis, reaction with NO and VOCs) was 80 %–90 % during the night and ∼ 50 % during the day. In terms of chemical losses of α -pinene below canopy height in the clearing, we find that at nighttime hydroxyl radicals (OH) and ozone (O3) dominate, with NO3 contributing "only" 17 %, which decreases further to 8.5 % during the day. Based on measured OH, measured O3 , and calculated NO3 concentrations, the chemical lifetime of BVOCs at noon is about 1 h and is likely to be longer than timescales of transport out of the canopy (typically of the order of minutes), thus significantly reducing the importance of daytime in-canopy processing. Clearly, in forested regions where sufficient nitric oxide and nitrogen dioxide (NOx) is available, the role of NO3 and OH as initiators of BVOC oxidation is not strictly limited to nighttime and daytime, respectively, as often implied in e.g. atmospheric chemistry textbooks. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. A 2-year intercomparison of three methods for measuring black carbon concentration at a high-altitude research station in Europe.
- Author
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Tinorua, Sarah, Denjean, Cyrielle, Nabat, Pierre, Pont, Véronique, Arnaud, Mathilde, Bourrianne, Thierry, Dias Alves, Maria, and Gardrat, Eric
- Subjects
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SOOT , *CARBON-black , *HEALTH impact assessment , *ABSORPTION cross sections , *DUST , *LOGNORMAL distribution , *CLIMATE change & health - Abstract
Black carbon (BC) is one of the most important climate forcers with severe health effects. Large uncertainties in radiative forcing estimation and health impact assessment arise from the fact that there is no standardized method to measure BC mass concentration. This study presents a 2-year comparison of three state-of-the-art BC measurement techniques at the high-altitude research station Pic du Midi (PDM) located in the French Pyrenees at an altitude of 2877 m above sea level. A recently upgraded Aethalometer AE33, a thermal-optical analyser Sunset and a single-particle soot photometer SP2 were deployed to measure simultaneously the mass concentration of equivalent black carbon (MeBC), elemental carbon (MEC) and refractory black carbon (MrBC), respectively. Significant deviations in the response of the instruments were observed. All techniques responded to seasonal variations in the atmospheric changes in BC levels and exhibited good correlation during the whole study period. This indicates that the different instruments quantified the same particle type despite the fact that they are based on different physical principles. However the slopes and correlation coefficients varied between instrument pairs. The largest biases were observed for the AE33 with MeBC values that were around 2 times greater than MrBC and MEC values. The principal reasons of such large discrepancy were explained by the mass absorption cross section (MAC) that was too low and C values recommended by the AE33 manufacturer and applied to the absorption coefficients measured by the AE33. In addition, the long-range transport of dust particles at PDM in spring caused significant increases in the bias between AE33 and SP2 by up to a factor 8. The Sunset MEC measurements agreed within around 17 % with the SP2 MrBC values. The largest overestimations of MEC were observed when the total carbon concentrations were below 25 µgCcm-2 , which is probably linked to the incorrect determination of the organic carbon (OC)–EC split point. Another cause of the discrepancy between instruments was found to be the limited detection range of the SP2, which did not allow for the total detection of fine rBC particles. The procedure used to estimate the missing mass fraction of rBC not covered by the measurement range of the SP2 was found to be critical. We found that a time-dependent correction based on fitting the observed rBC size distribution with a multimodal lognormal distribution is needed to accurately estimate MrBC over a larger size range. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
9. Supplementary material to "Measurement report: Sources, sinks and lifetime of NOX in a sub-urban temperate forest at night"
- Author
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Andersen, Simone T., primary, McGillen, Max R., additional, Xue, Chaoyang, additional, Seubert, Tobias, additional, Dewald, Patrick, additional, Türk, Gunther N. T. E., additional, Schuladen, Jan, additional, Denjean, Cyrielle, additional, Etienne, Jean-Claude, additional, Garrouste, Olivier, additional, Jamar, Marina, additional, Harb, Sergio, additional, Cirtog, Manuela, additional, Michoud, Vincent, additional, Cazaunau, Mathieu, additional, Bergé, Antonin, additional, Cantrell, Christopher, additional, Dusanter, Sebastien, additional, Picquet-Varrault, Bénédicte, additional, Kukui, Alexandre, additional, Mellouki, Abdelwahid, additional, Carpenter, Lucy J., additional, Lelieveld, Jos, additional, and Crowley, John N., additional
- Published
- 2024
- Full Text
- View/download PDF
10. Measurement report: Sources, sinks and lifetime of NOX in a sub-urban temperate forest at night
- Author
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Andersen, Simone T., primary, McGillen, Max R., additional, Xue, Chaoyang, additional, Seubert, Tobias, additional, Dewald, Patrick, additional, Türk, Gunther N. T. E., additional, Schuladen, Jan, additional, Denjean, Cyrielle, additional, Etienne, Jean-Claude, additional, Garrouste, Olivier, additional, Jamar, Marina, additional, Harb, Sergio, additional, Cirtog, Manuela, additional, Michoud, Vincent, additional, Cazaunau, Mathieu, additional, Bergé, Antonin, additional, Cantrell, Christopher, additional, Dusanter, Sebastien, additional, Picquet-Varrault, Bénédicte, additional, Kukui, Alexandre, additional, Mellouki, Abdelwahid, additional, Carpenter, Lucy J., additional, Lelieveld, Jos, additional, and Crowley, John N., additional
- Published
- 2024
- Full Text
- View/download PDF
11. NO3 reactivity during a summer period in a temperate forest below and above the canopy.
- Author
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Dewald, Patrick, Seubert, Tobias, Andersen, Simone T., Türk, Gunther N. T. E., Schuladen, Jan, McGillen, Max R., Denjean, Cyrielle, Etienne, Jean-Claude, Garrouste, Olivier, Jamar, Marina, Harb, Sergio, Cirtog, Manuela, Michoud, Vincent, Cazaunau, Mathieu, Bergé, Antonin, Cantrell, Christopher, Dusanter, Sebastien, Picquet-Varrault, Bénédicte, Kukui, Alexandre, and Chaoyang Xue
- Abstract
We present direct measurements of BVOC-induced nitrate radical (NO
3 ) reactivity (kVOC ) through the diel cycle in the suburban, temperate forest of Rambouillet near Paris (France). The data were obtained in a six-week summer period in 2022 as part of the ACROSS campaign (Atmospheric ChemistRy Of the Suburban foreSt). kVOC was measured in a small (700 m²) clearing mainly at a height of 5.5 m above ground level, but also at 40 m (for 5 days/nights). At nighttime, mean values of kVOC night (5.5 m) = (0.24 ± 0.27) s-1 and kVOC night (40 m) = (0.016 ± 0.007) s-1 indicate a significant vertical gradient and low NO3 reactivity above the canopy, whereas kVOC night (5.5 m) showed peak values of up to 2 s-1 close to the ground. The strong vertical gradient in NO3 reactivity could be confirmed by measurements between 0 and 24 m on one particular night characterised by a strong temperature inversion, and is a result of the decoupling of air masses aloft from the ground- and canopy-level sources of BVOCs (and NO). No strong vertical gradient was observed in the mean daytime NO3 reactivity with kVOC night (5.5 m) = (0.12 ± 0.04) s-1 for the entire campaign and kVOC night (40 m) = (0.07 ± 0.02) s-1 during the 5-day period. Within the clearing, the fractional contribution of VOCs to the total NO3 loss rate (LNO3 , determined by photolysis, reaction with NO and VOCs) was 80-90 % during the night and ~50 % during the day. In terms of chemical losses of α-pinene below canopy height in the clearing, we find that at nighttime OH and O3 dominate with NO3 contributing "only" 17 %, which decreases further to 8.5 % during the day. Based on OH, O3 and NO3 concentrations, the chemical lifetime of BVOCs at noon is about one hour and is likely to be longer than timescales of transport out of the canopy (typically in the order of minutes), thus significantly reducing the importance of daytime, in-canopy processing. Clearly, in forested regions where sufficient NOX is available, the role of NO3 and OH as initiators of BVOC oxidation are not strictly limited to the night and to the day, respectively, as often implied in e.g. atmospheric chemistry text-books. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
12. The impact of aerosols on stratiform clouds over southern West Africa: a large-eddy-simulation study
- Author
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Delbeke, Lambert, primary, Wang, Chien, additional, Tulet, Pierre, additional, Denjean, Cyrielle, additional, Zouzoua, Maurin, additional, Maury, Nicolas, additional, and Deroubaix, Adrien, additional
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- 2023
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- View/download PDF
13. THE AEROSOLS, RADIATION AND CLOUDS IN SOUTHERN AFRICA FIELD CAMPAIGN IN NAMIBIA : Overview, Illustrative Observations, and Way Forward
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Formenti, Paola, D’Anna, Barbara, Flamant, Cyrille, Mallet, Marc, Piketh, Stuart John, Schepanski, Kerstin, Waquet, Fabien, Auriol, Frédérique, Brogniez, Gerard, Burnet, Frédéric, Chaboureau, Jean-Pierre, Chauvigné, Aurélien, Chazette, Patrick, Denjean, Cyrielle, Desboeufs, Karine, Doussin, Jean-François, Elguindi, Nellie, Feuerstein, Stefanie, Gaetani, Marco, Giorio, Chiara, Klopper, Danitza, Mallet, Marc Daniel, Nabat, Pierre, Monod, Anne, Solmon, Fabien, Namwoonde, Andreas, Chikwililwa, Chibo, Mushi, Roland, Welton, Ellsworth Judd, and Holben, Brent
- Published
- 2019
14. Higher absorption enhancement of black carbon in summer shown by 2-year measurements at the high-altitude mountain site of Pic du Midi Observatory in the French Pyrenees.
- Author
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Tinorua, Sarah, Denjean, Cyrielle, Nabat, Pierre, Bourrianne, Thierry, Pont, Véronique, Gheusi, François, and Leclerc, Emmanuel
- Subjects
ATMOSPHERIC boundary layer ,CARBON-black ,ATMOSPHERIC circulation ,CLIMATE change models ,OBSERVATORIES ,SUMMER ,MOUNTAIN soils - Abstract
Black-carbon-containing particles strongly absorb light, causing substantial radiative heating of the atmosphere. The climate-relevant properties of black carbon (BC) are poorly constrained in high-altitude mountain regions, where many complex interactions between BC, radiation, clouds and snow have important climate implications. This study presents 2-year measurements of BC microphysical and optical properties at the Pic du Midi (PDM) research station, a high-altitude observatory located at 2877 m above sea level in the French Pyrenees. Among the long-term monitoring sites in the world, PDM is subject to limited influence from the planetary boundary layer (PBL), making it a suitable site for characterizing the BC in the free troposphere (FT). The classification of the dominant aerosol type using aerosol spectral optical properties indicates that BC is the predominant aerosol absorption component at PDM and controls the variation in single-scattering albedo (SSA) throughout the 2 years. Single-particle soot photometer (SP2) measurements of refractory BC (rBC) show a mean mass concentration (MrBC) of 35 ngm-3 and a relatively constant rBC core mass-equivalent diameter of about 180 nm, which are typical values for remote mountain sites. Combining the MrBC with in situ absorption measurements, a rBC mass absorption cross-section (MAC rBC) of 9.2 ± 3.7 m2g-1 at λ=880 nm has been obtained, which corresponds to an absorption enhancement (Eabs) of ∼2.2 compared to that of bare rBC particles with equal rBC core size distribution. A significant reduction in the ΔMrBC/ΔCO ratio when precipitation occurred along the air mass transport suggests wet removal of rBC. However we found that the wet removal process did not affect the rBC size, resulting in unchanged Eabs. We observed a large seasonal contrast in rBC properties with higher MrBC and Eabs in summer than in winter. In winter a high diurnal variability in MrBC (Eabs) with higher (lower) values in the middle of the day was linked to the injection of rBC originating from the PBL. On the contrary, in summer, MrBC showed no diurnal variation despite more frequent PBL conditions, implying that MrBC fluctuations are rather dominated by regional and long-range transport in the FT. Combining the ΔMrBC/ΔCO ratio with air mass transport analysis, we observed additional sources from biomass burning in summer leading to an increase in MrBC and Eabs. The diurnal pattern of Eabs in summer was opposite to that observed in winter with maximum values of ∼2.9 observed at midday. We suggest that this daily variation may result from a photochemical process driving the rBC mixing state rather than a change in BC emission sources. Such direct 2-year observations of BC properties provide quantitative constraints for both regional and global climate models and have the potential to close the gap between model-predicted and observed effects of BC on the regional radiation budget and climate. The results demonstrate the complex influence of BC emission sources, transport pathways, atmospheric dynamics and chemical reactivity in driving the light absorption of BC. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Two-year intercomparison of three methods for measuring black carbon concentration at a high-altitude research station in Europe.
- Author
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Tinorua, Sarah, Denjean, Cyrielle, Nabat, Pierre, Pont, Véronique, Arnaud, Mathilde, Bourrianne, Thierry, Alves, Maria Dias, and Gardrat, Eric
- Subjects
SOOT ,CARBON-black ,HEALTH impact assessment ,DUST ,LOGNORMAL distribution ,PARTICULATE matter ,CARBONACEOUS aerosols - Abstract
Black carbon (BC) is one of the most important climate forcer with severe health effects. Large uncertainties in radiative forcing estimation and health impact assessment arise from the fact that there is no standardized method to measure BC mass concentration. This study presents a two-year comparison of three state-of-the-art BC measurement techniques at the high-altitude research station Pic du Midi located in the French Pyrenees at an altitude of 2877 m above sea level. A recently upgraded aethalometer AE33, a thermal-optical analyzer Sunset and a single-particle soot photometer SP2 were deployed to measure simultaneously the mass concentration of equivalent black carbon (M
eBC ), elemental carbon (MEC ) and refractory black carbon (MrBC ), respectively. Significant deviations in the response of the instruments were observed. All techniques responded to seasonal variations of the atmospheric changes in BC levels and exhibited good correlation during the whole study period. This indicates that the different instruments quantified the same particle type, despite the fact that they are based on different physical principles. However the slopes and correlation coefficients varied between instrument pairs. The largest biases were observed for the AE33 with MeBC values that were around 2 times greater than MrBC and MEC values. The principal reasons of such large discrepancy was explained by the too low MAC and C values recommended by the AE33 manufacturer and applied to the absorption coefficients measured by the AE33. In addition, the long-range transport of dust particles at PDM in spring caused significant increases in the bias between AE33 and SP2 by up to a factor 8. The Sunset MEC measurements agreed within around 17 % with the SP2 MrBC values. The largest overestimations of MEC were observed when the total carbon concentration were below 25 µ gC cm−2 , which is probably linked to the incorrect determination of the OC-EC split point. Another cause of the discrepancy between instruments was found to be the limited detection range of the SP2, which did not allow the total detection of fine rBC particles. The procedure used to estimate the missing mass fraction of rBC not covered by the measurement range of the SP2 was found to be critical. We found that a time-dependent correction based on fitting the observed rBC size distribution with a multimodal lognormal distribution are needed to accurately estimate MrBC over a larger size range. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
16. Measurement report: Sources, sinks and lifetime of NOX in a sub-urban temperate forest at night.
- Author
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Andersen, Simone T., McGillen, Max R., Xue, Chaoyang, Seubert, Tobias, Dewald, Patrick, Türk, Gunther N. T. E., Schuladen, Jan, Denjean, Cyrielle, Etienne, Jean-Claude, Garrouste, Olivier, Jamar, Marina, Harb, Sergio, Cirtog, Manuela, Michoud, Vincent, Cazaunau, Mathieu, Bergé, Antonin, Cantrell, Christopher, Dusanter, Sebastien, Picquet-Varrault, Bénédicte, and Kukui, Alexandre
- Subjects
TEMPERATURE inversions ,SURFACE resistance ,BOUNDARY layer (Aerodynamics) ,REACTIVE nitrogen species ,TEMPERATE forests ,HUMIDITY - Abstract
Through observations of NO, NO
2 , NOY and O3 in the Rambouillet forest near Paris, France, (as part of the ACROSS campaign, 2022) we have gained insight into nighttime processes controlling NOX in an anthropogenically impacted forest environment. O3 mixing ratios displayed a strong diel profile at the site, which was driven by a variable but generally rapid deposition to soil and foliar surfaces. The O3 diel profile was strongly influenced by relative humidity, which impacted the surface resistance to uptake, and temperature inversion, which influenced the rate of entrainment of O3 from above the canopy. Only when the O3 mixing ratio was sufficiently low (and thus the NO lifetime sufficiently long), were sustained NO peaks observed above the instrumental detection limit, enabling derivation of average NO emission rates from the soil of ~1.4 ppbv h‑1 . Observations of the lack of increase in NO2 at night, despite a significant production rate from the reaction of NO with O3 , enabled an effective lifetime of NO2 of ⁓0.5–3 h to be derived. As the loss of NO2 was not compensated by the formation of gas- or particle-phase reactive nitrogen species it was presumably driven by deposition to soil and foliar surfaces, or any products formed were themselves short-lived with respect to deposition. By comparison, the daytime lifetime of NO2 with respect to loss by reaction with OH is about 1 day. We conclude that the nighttime deposition of NO2 is a major sink of boundary layer NOX in this temperate forest environment. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
17. Measurement report: Sources, sinks and lifetime of NOX in a sub-urban temperate forest at night.
- Author
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Andersen, Simone T., McGillen, Max R., Chaoyang Xue, Seubert, Tobias, Dewald, Patrick, Türk, Gunther N. T. E., Schuladen, Jan, Denjean, Cyrielle, Etienne, Jean-Claude, Garrouste, Olivier, Jamar, Marina, Harb, Sergio, Cirtog, Manuela, Michoud, Vincent, Cazaunau, Mathieu, Bergé, Antonin, Cantrell, Christopher, Dusanter, Sebastien, Varrault, Bénédicte Picquet, and Kukui, Alexandre
- Abstract
Through observations of NO, NO
2 , NOY and O3 in the Rambouillet forest near Paris, France, (as part of the ACROSS campaign, 2022) we have gained insight into nighttime processes controlling NOX in an anthropogenically impacted forest environment. O3 mixing ratios displayed a strong diel profile at the site, which was driven by a variable but generally rapid deposition to soil and foliar surfaces. The O3 diel profile was strongly influenced by relative humidity, which impacted the surface resistance to uptake, and temperature inversion, which influenced the rate of entrainment of O3 from above the canopy. Only when the O3 mixing ratio was sufficiently low (and thus the NO lifetime sufficiently long), were sustained NO peaks observed above the instrumental detection limit, enabling derivation of average NO emission rates from the soil of -1.4 ppbv h-1 . Observations of the lack of increase in NO2 at night, despite a significant production rate from the reaction of NO with O3 , enabled an effective lifetime of NO2 of -0.5-3 h to be derived. As the loss of NO2 was not compensated by the formation of gas- or particle-phase reactive nitrogen species it was presumably driven by deposition to soil and foliar surfaces, or any products formed were themselves short-lived with respect to deposition. By comparison, the daytime lifetime of NO2 with respect to loss by reaction with OH is about 1 day. We conclude that the nighttime deposition of NO2 is a major sink of boundary layer NOX in this temperate forest environment. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
18. Two-year measurements of Black Carbon properties at the high-altitude mountain site of Pic du Midi Observatory in the French Pyrenees
- Author
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Tinorua, Sarah, primary, Denjean, Cyrielle, additional, Nabat, Pierre, additional, Bourrianne, Thierry, additional, Pont, Véronique, additional, Gheusi, François, additional, and Leclerc, Emmanuel, additional
- Published
- 2023
- Full Text
- View/download PDF
19. Supplementary material to "Two-year measurements of Black Carbon properties at the high-altitude mountain site of Pic du Midi Observatory in the French Pyrenees"
- Author
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Tinorua, Sarah, primary, Denjean, Cyrielle, additional, Nabat, Pierre, additional, Bourrianne, Thierry, additional, Pont, Véronique, additional, Gheusi, François, additional, and Leclerc, Emmanuel, additional
- Published
- 2023
- Full Text
- View/download PDF
20. The Impact of Aerosols on the Stratiform Clouds over southern West Africa: A Large-Eddy Simulation Study
- Author
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Delbeke, Lambert, primary, Wang, Chien, additional, Tulet, Pierre, additional, Denjean, Cyrielle, additional, Zouzoua, Maurin, additional, Maury, Nicolas, additional, and Deroubaix, Adrien, additional
- Published
- 2023
- Full Text
- View/download PDF
21. Butene Emissions From Coastal Ecosystems May Contribute to New Particle Formation
- Author
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Giorio, Chiara, Doussin, Jean‐François, D’Anna, Barbara, Mas, Sébastien, Filippi, Daniele, Denjean, Cyrielle, Mallet, Marc Daniel, Bourrianne, Thierry, Burnet, Frédéric, Cazaunau, Mathieu, Chikwililwa, Chibo, Desboeufs, Karine, Feron, Anaïs, Michoud, Vincent, Namwoonde, Andreas, Andreae, Meinrat O, Piketh, Stuart J, Formenti, Paola, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Chimie de l'environnement (LCE), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Observatoire de REcherche Méditerranéen de l'Environnement (OSU OREME), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Giorio, Chiara [0000-0001-7821-7398], Doussin, Jean‐François [0000-0002-8042-7228], D’Anna, Barbara [0000-0003-1985-229X], Denjean, Cyrielle [0000-0001-5559-5732], Mallet, Marc Daniel [0000-0003-2749-8833], Cazaunau, Mathieu [0000-0003-4024-8978], Namwoonde, Andreas [0000-0003-1209-2574], Andreae, Meinrat O [0000-0003-1968-7925], Formenti, Paola [0000-0002-0372-1351], Apollo - University of Cambridge Repository, Université Montpellier 2 - Sciences et Techniques (UM2)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université de Montpellier (UM), Giorio, C [0000-0001-7821-7398], Doussin, JF [0000-0002-8042-7228], D’Anna, B [0000-0003-1985-229X], Denjean, C [0000-0001-5559-5732], Mallet, MD [0000-0003-2749-8833], Cazaunau, M [0000-0003-4024-8978], Namwoonde, A [0000-0003-1209-2574], Andreae, MO [0000-0003-1968-7925], and Formenti, P [0000-0002-0372-1351]
- Subjects
13 Climate Action ,Geophysics ,[SDU]Sciences of the Universe [physics] ,[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology ,3701 Atmospheric Sciences ,General Earth and Planetary Sciences ,37 Earth Sciences ,41 Environmental Sciences - Abstract
International audience; Marine ecosystems are important drivers of the global climate system. They emit volatile species into the atmosphere, involved in complex reaction cycles that influence the lifetime of greenhouse gases. Sea spray and marine biogenic aerosols affect Earth's climate by scattering solar radiation and controlling cloud microphysical properties. Here we show larger than expected marine biogenic emissions of butenes, three orders of magnitude higher than dimethyl sulfide, produced by the coastal part of the Benguela upwelling system, one of the most productive marine ecosystems in the world. We show that these emissions may contribute to new particle formation in the atmosphere within the marine boundary layer through production of Criegee intermediates that oxidize SO2 to H2SO4. Butene emissions from the marine biota may affect air quality and climate through ozone, secondary organic aerosol, and cloud condensation nuclei formation even in pristine regions of the world. Our results indicate a potentially important role of butene emissions in marine particle formation that requires investigation in other regions.
- Published
- 2022
22. Experimental study on the evolution of droplet size distribution during the fog life cycle
- Author
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Mazoyer, Marie, primary, Burnet, Frédéric, additional, and Denjean, Cyrielle, additional
- Published
- 2022
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23. Sensitivity analysis of an aerosol-aware microphysics scheme in Weather Research and Forecasting (WRF) during case studies of fog in Namibia
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Weston, Michael John, primary, Piketh, Stuart John, additional, Burnet, Frédéric, additional, Broccardo, Stephen, additional, Denjean, Cyrielle, additional, Bourrianne, Thierry, additional, and Formenti, Paola, additional
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- 2022
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24. Two-year measurements of Black Carbon properties at the high-altitude mountain site of Pic du Midi Observatory in the French Pyrenees.
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Tinorua, Sarah, Denjean, Cyrielle, Nabat, Pierre, Bourrianne, Thierry, Pont, Véronique, Gheusi, François, and Leclerc, Emmanuel
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ATMOSPHERIC boundary layer ,CLIMATE change models ,OBSERVATORIES ,ATMOSPHERIC circulation ,CARBON-black ,ATMOSPHERE - Abstract
Black Carbon containing particles (BC) are strong light absorbers, causing substantial radiative heating of the atmosphere. The climate-relevant properties of BC are poorly constrained in high-elevation mountain regions, where numerous complex interactions between BC, radiation, clouds and snow have important climate implications. This study presents two-year measurements of BC microphysical and optical properties at the research station of Pic du Midi (PDM), a high-altitude observatory located at 2877 m above sea level in the French Pyrenees. Among the worldwide existing long-term monitoring sites, PDM has experiences limited influence of the planetary boundary layer (PBL), making it an appropriate site for characterizing free tropospheric (FT) BC. The classification of the dominant aerosol type using the spectral optical properties of the aerosols indicates that BC was the predominant absorption component of aerosols at PDM and controlled the variation of Single Scattering Albedo (SSA) throughout the two years. Single-particle soot photometer (SP2) measurements showed a mean mass concentrations of BC (M
BC ) of 35 ng m−3 and a relatively constant BC core mass-equivalent diameter of around 180 nm, which are typical values for remote mountain sites. Combining the MBC with in situ absorption measurements yielded a BC mass absorption coefficient (MACBC ) of 9.8 ± 2.7 m2 g−1 at 880 nm, which corresponds to an absorption enhancement (Eabs ) of 2.4 compared to that of bare BC particles with equal BC core size distribution. A significant reduction of the ratio ∆BC / ∆CO when precipitation occurred along the air mass transport suggests wet removal of BC. However we found that the wet removal process did not affect the size of BC, resulting in unchanged Eabs . We observed a large seasonal contrast in BC properties with higher MBC and Eabs in summer than winter. In winter a strong diurnal variability of MBC (Eabs ) with higher (lower) values in the middle of the day was linked to the injection of BC originating from the PBL. During summer in contrast, MBC showed no diurnal variation was rather constant despite more frequent PBL-conditions, implying that MBC fluctuations were rather dominated by regional and long-range transport in the FT. A body of evidence suggests that biomass burning emissions effectively altered the concentration and optical properties of BC at PDM, leading to higher Eabs in summer compared to winter. The diurnal pattern of Eabs in summer was opposite to that observed in winter with maximum values of 2.9 observed at noon. We suggest that this daily variation results from photochemical processing driving BC mixing state rather than a change in BC emission source. Such direct two-year observations of BC properties provide quantitative constraints for both regional and global climate models and have the potential to close the gap between model predicted and observed effects of BC on regional radiation budget and climate. The results demonstrates the complex influence of BC emission sources, transport pathways, atmospheric dynamics and chemical reactivity in driving the light absorption of BC. [ABSTRACT FROM AUTHOR]- Published
- 2023
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25. Atmospheric Chemistry in the Mediterranean Region ((Vol. 2, From air pollutant sources to impacts)Aerosol optical propertie
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Dulac, François, Sauvage, Stéphane, Hamonou, Eric, Mallet, Marc, Chazette, Patrick, Formenti, Paola, Di, Biagio C., Denjean, Cyrielle, Chiapello, Isabelle, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Chimie Atmosphérique Expérimentale (CAE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT), Centre for Energy and Environment (CERI EE - IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere - Abstract
International audience
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- 2022
26. The Impact of Aerosols on the Stratiform Clouds over southern West Africa: A Large-Eddy Simulation Study.
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Delbeke, Lambert, Chien Wang, Tulet, Pierre, Denjean, Cyrielle, Zouzoua, Maurin, Maury, Nicolas, and Deroubaix, Adrien
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Low level stratiform clouds (LLSCs), covering a large area, appear frequently during the wet monsoon season in southernWest Africa. This region is also the place where different types of aerosols coexist, including biomass burning aerosols coming from Central and South Africa and anthropogenic aerosols emitted by local activities. We investigate the semi-direct and indirect effects of these aerosols on the diurnal cycle of LLSCs by constructing a case study based on aircraft-based and ground-based observations from the Dynamic-Aerosol-Chemistry-Cloud-Interaction in West Africa (DACCIWA) field campaign. This case is modelled using a Large Eddy Simulation (LES) model with fine scale resolution and in-situ aerosol measurements including size distribution and chemical composition. The model has successfully reproduced the observed life cycle of the LLSC, from stratus formation to stabilization during the night, to upward development after sunrise until break-up of cloud deck in afternoon. Various sensitivity simulations using different measured aerosol profiles based on measurements also suggest that aerosols can affect the cloud life cycle through both the indirect and semi-direct effect. Despite precipitation produced by the modeled cloud is nearly negligible, clouds lifetime is still sensitive to the aerosol concentration. As expected, modeled cloud microphysical features including cloud droplet number concentration, mean radius, and thus cloud reflectivity are all controlled by aerosol concentration. However, it is found that the difference in cloud reflectivity is not always the only factor in determining the variation of the incoming solar radiation at ground and cloud life cycle specifically beyond sunrise. Instead, the difference in cloud-void space brought by dry air entrainment from above and thus the speed of consequent evaporation - also influenced by aerosol concentration, is an another important factor to consider. Results have shown that clouds in the case with lower aerosol concentration and larger droplet size appear to be less affected by entrainment and convection. In addition, we found that an excessive atmospheric heating up to 12 K day
-1 produced by absorbing black carbon aerosols (BC) in our modeled cases can also affect the life cycle of modeled clouds. Such a heating is found to lower the height of cloud top and stabilize the cloud layer, resulting a less extent in vertical development and accelerating clouds break-up. The semi-direct effect impacts on indirect effect by reducing cloud reflectivity particularly in case of polluted environment. Finally, semi-direct effect is found to contribute positively to the indirect radiative forcing due to a decreased cloud-void space, and negatively by causing thinner clouds that would break-up faster in late afternoon, all depending on the phase in stratiform cloud diurnal cycle. [ABSTRACT FROM AUTHOR]- Published
- 2023
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27. Sensitivity analysis of an aerosol aware microphysics scheme in WRF during case studies of fog in Namibia
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Weston, Michael, primary, Piketh, Stuart, additional, Burnet, Frédéric, additional, Broccardo, Stephen, additional, Denjean, Cyrielle, additional, Bourrianne, Thierry, additional, and Formenti, Paola, additional
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- 2022
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28. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study
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Deroubaix, Adrien, primary, Menut, Laurent, additional, Flamant, Cyrille, additional, Knippertz, Peter, additional, Fink, Andreas H., additional, Batenburg, Anneke, additional, Brito, Joel, additional, Denjean, Cyrielle, additional, Dione, Cheikh, additional, Dupuy, Régis, additional, Hahn, Valerian, additional, Kalthoff, Norbert, additional, Lohou, Fabienne, additional, Schwarzenboeck, Alfons, additional, Siour, Guillaume, additional, Tuccella, Paolo, additional, and Voigt, Christiane, additional
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- 2022
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29. Une campagne de mesures sur le climat urbain et la qualité de l'air de la région parisienne
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Masson, Valéry, primary, Lemonsu, Aude, additional, Martinet, Pauline, additional, Denjean, Cyrielle, additional, Boissard, Christophe, additional, Cantrell, Chris, additional, Michoud, Vincent, additional, Gros, Valérie, additional, Haeffelin, Martial, additional, Kotthaus, Simone, additional, Leymarie, Juliette, additional, Madelin, Malika, additional, and Price, Jeremy, additional
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- 2022
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30. Measurement report: Comparison of airborne, in situ measured, lidar-based, and modeled aerosol optical properties in the central European background – identifying sources of deviations
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Düsing, Sebastian, primary, Ansmann, Albert, additional, Baars, Holger, additional, Corbin, Joel C., additional, Denjean, Cyrielle, additional, Gysel-Beer, Martin, additional, Müller, Thomas, additional, Poulain, Laurent, additional, Siebert, Holger, additional, Spindler, Gerald, additional, Tuch, Thomas, additional, Wehner, Birgit, additional, and Wiedensohler, Alfred, additional
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- 2021
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31. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study
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Deroubaix, Adrien, primary, Menut, Laurent, additional, Flamant, Cyrille, additional, Knippertz, Peter, additional, Fink, Andreas, additional, Batenburg, Anneke, additional, Brito, Joel, additional, Denjean, Cyrielle, additional, Dione, Cheikh, additional, Dupuy, Régis, additional, Hahn, Valerian, additional, Kalthoff, Norbert, additional, Lohou, Fabienne, additional, Schwarzenboeck, Alfons, additional, Siour, Guillaume, additional, Tuccella, Paolo, additional, and Voigt, Christiane, additional
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- 2021
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32. Closure of In-Situ Measured Aerosol Backscattering and Extinction Coefficients with Lidar Accounting for Relative Humidity
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Düsing, Sebastian, primary, Ansmann, Albert, additional, Baars, Holger, additional, Corbin, Joel C., additional, Denjean, Cyrielle, additional, Gysel-Beer, Martin, additional, Müller, Thomas, additional, Poulain, Laurent, additional, Siebert, Holger, additional, Spindler, Gerald, additional, Tuch, Thomas, additional, Wehner, Birgit, additional, and Wiedensohler, Alfred, additional
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- 2021
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33. Unexpected Biomass Burning Aerosol Absorption Enhancement Explained by Black Carbon Mixing State
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Denjean, Cyrielle, primary, Brito, Joel, additional, Libois, Quentin, additional, Mallet, Marc, additional, Bourrianne, Thierry, additional, Burnet, Frederic, additional, Dupuy, Régis, additional, Flamant, Cyrille, additional, and Knippertz, Peter, additional
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- 2020
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34. Sensitivity analysis of an aerosol aware microphysics scheme in WRF during case studies of fog in Namibia.
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Weston, Michael, Piketh, Stuart, Burnet, Frédéric, Broccardo, Stephen, Denjean, Cyrielle, Bourrianne, Thierry, and Formenti, Paola
- Abstract
Aerosol aware microphysics parameterisation schemes are increasingly being introduced into numerical weather prediction models, allowing for regional and case specific parameterisation of cloud condensation nuclei (CCN) and cloud droplet interactions. In this paper, the Thompson aerosol aware microphysics scheme, within the Weather, Research and Forecasting (WRF) model, is parameterised for two fog cases during September 2017 over Namibia. Measurements of CCN and fog microphysics were undertaken during the Aerosol, Radiation and Clouds in southern Africa (AEROCLO-sA) field campaign at Henties Bay on the coast of Namibia during September 2017. A key concept of the microphysics scheme is the conversion of water friendly aerosols to cloud droplets (hereafter referred to as CCN activation), which could be estimated from the observations. A fog monitor 100 (FM100) provided cloud droplet size distribution, number concentration (N
t ), liquid water content (LWC) and mean volumetric diameter (MVD). These measurements are used to evaluate and parameterise WRF model simulations of Nt , LWC and MVD. A sensitivity analysis was conducted through variations to the initial CCN concentration, CCN radius and the minimum updraft speed, important factors that influence droplet activation in the microphysics scheme of the model. The first model scenario made use of the default settings with a constant initial CCN number concentration of 300 cm-3 and underestimated the cloud droplet number concentration while the LWC was in good agreement with the observations. This resulted in droplet size being larger than the observations. Another scenario used modelled data as CCN initial conditions which were an order of magnitude higher than other scenarios. However, these provided the most realistic values of Nt , LWC, MVD and droplet size distribution. From this it was concluded that CCN activation of around 10 % in the simulations is too low, while the observed appears to be higher reaching between with a mean (median) of 0.55 (0.56) during fog events. To achieve this level of activation in the model, the minimum updraft speed for CCN activation was increased from 0.01 to 0.1 ms-1 . This scenario provided Nt , LWC, MVD and droplet size distribution in the range of the observations with the added benefit of a realistic initial CCN concentration. These results demonstrate the benefits of a dynamic aerosol aware scheme when parameterised with observations. [ABSTRACT FROM AUTHOR]- Published
- 2022
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35. Overview of aerosol optical properties over southern West Africa from DACCIWA aircraft measurements
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Denjean, Cyrielle, primary, Bourrianne, Thierry, additional, Burnet, Frederic, additional, Mallet, Marc, additional, Maury, Nicolas, additional, Colomb, Aurélie, additional, Dominutti, Pamela, additional, Brito, Joel, additional, Dupuy, Régis, additional, Sellegri, Karine, additional, Schwarzenboeck, Alfons, additional, Flamant, Cyrille, additional, and Knippertz, Peter, additional
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- 2020
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36. The SOuth west FOGs 3D experiment for processes study (SOFOG3D) project
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Burnet, Frédéric, primary, Lac, Christine, additional, Martinet, Pauline, additional, Fourrié, Nadia, additional, Haeffelin, Martial, additional, Delanoë, Julien, additional, Price, Jeremy, additional, Barrau, Sébastien, additional, Canut, Guylaine, additional, Cayez, Grégoire, additional, Dabas, Alain, additional, Denjean, Cyrielle, additional, Dupont, Jean-Charles, additional, Honnert, Rachel, additional, Mahfouf, Jean-François, additional, Montmerle, Thibault, additional, Roberts, Greg, additional, Seity, Yann, additional, and Vié, Benoit, additional
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- 2020
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37. Remote biomass burning dominates southern West African air pollution during the monsoon
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Haslett, Sophie L., primary, Taylor, Jonathan W., additional, Evans, Mathew, additional, Morris, Eleanor, additional, Vogel, Bernhard, additional, Dajuma, Alima, additional, Brito, Joel, additional, Batenburg, Anneke M., additional, Borrmann, Stephan, additional, Schneider, Johannes, additional, Schulz, Christiane, additional, Denjean, Cyrielle, additional, Bourrianne, Thierry, additional, Knippertz, Peter, additional, Dupuy, Régis, additional, Schwarzenböck, Alfons, additional, Sauer, Daniel, additional, Flamant, Cyrille, additional, Dorsey, James, additional, Crawford, Ian, additional, and Coe, Hugh, additional
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- 2019
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38. Response to referees
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Denjean, Cyrielle, primary
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- 2019
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39. Sensitivity of low-level clouds and precipitation to anthropogenic aerosol emission in southern West Africa: a DACCIWA case study.
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Deroubaix, Adrien, Menut, Laurent, Flamant, Cyrille, Knippertz, Peter, Fink, Andreas, Batenburg, Anneke, Brito, Joel, Denjean, Cyrielle, Dione, Cheikh, Dupuy, Régis, Hahn, Valerian, Kalthoff, Norbert, Lohou, Fabienne, Schwarzenboeck, Alfons, Siour, Guillaume, Tuccella, Paolo, and Voigt, Christiane
- Abstract
During the West African summer monsoon, pollutants emitted in urbanized coastal areas modify cloud cover and precipitation patterns. The Dynamics-Aerosol-Chemistry-Cloud-Interactions in West Africa (DACCIWA) field campaign provided numerous aircraft-based and ground-based observations, which are used here to evaluate two experiments made with the coupled WRF-CHIMERE model, integrating both the direct and indirect aerosol effect on meteorology. During one well-documented week (1-7 July 2016), the impacts of anthropogenic aerosols on the diurnal cycle of low-level clouds and precipitation are analyzed in detail using high and moderate intensity of anthropogenic emissions in the experiments. Over the continent and close to major anthropogenic emission sources, the breakup time of low-level clouds is delayed by one hour, and the daily precipitation rate decreased by 7.5 % with the enhanced anthropogenic emission experiment (with high aerosol load). Despite the small modifications on daily average of low-level cloud cover (+2.6 %) with high aerosol load compared to moderate, there is an increase by more than 20 % from 14:00 to 22:00 UTC on hourly average. Moreover, modifications of the modeled low-level cloud and precipitation rate occur far from the major anthropogenic emission sources, to the south over the ocean and to the north up to 11° N. The present study adds evidence to recent findings that enhanced pollution levels in West Africa may reduce precipitation. [ABSTRACT FROM AUTHOR]
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- 2021
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40. Observation of a very large and persistent mode of desert dust in African air masses transported over the Mediterranean Sea with drifting balloons
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Dulac, François, Renard, Jean-Baptiste, Durand, Pierre, Denjean, Cyrielle, Bourgeois, Quentin, Vignelles, Damien, Jeannot, Matthieu, Mallet, Marc, Verdier, Nicolas, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Centre National d'Études Spatiales [Toulouse] (CNES)
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[SDU]Sciences of the Universe [physics] - Abstract
International audience; The objective of this study was to document in situ the particle size distribution of desert dust particles during their long-range transport in the free troposphere, with a particular focus on the coarse size fraction that dominates the mass flux. The basic idea was to deploy a specifically designed optical particle counter/sizer named LOAC (Light Optical Aerosol Counter/sizer) under drifting balloons in order to minimize isokinetic sampling problems. Boundary-layer pressurized balloons (BLBPs) were launched on alert in the western Mediterranean basin in the framework of the Chemistry and Aerosol Mediterranean Experiment (ChArMEx) field campaigns, allowing us to perform original quasi-Lagrangian monitoring of desert dust aerosols over the sea. We illustrate tests and validations of LOAC measurements performed to qualify the instrument that include comparisons with concurrent aircraft and tethered balloon measurements, and remote sensing measurements including an AERONET sun-photometer, and a ground-based and the CALIOP lidar systems. As many as 10 LOAC flights were successfully conducted, mainly from Minorca Isl., Spain, during 4 Saharan dust transport events, with BLPBs drifting at altitudes between 2.0 and 3.3 km above sea level. The longest flight exceeded 700 km and lasted more than 25 h. Aerosol optical depths in the balloon vicinity did not exceed about 0.4 but the presence of turbid dust layers was confirmed thanks to dual scattering angle measurements by LOAC allowing the identification of dust particles. LOAC data from BLBPs could generally be fitted by a 3-mode lognormal distribution at roughly 0.2, 4 and 30 µm in modal diameter. Up to about 0.0001 dust particles per cubic cm larger than 40 µm are reported and no significant evolution of the size distribution was observed during the flights whereas we were expecting to observe gravitational sedimentation of the largest particle size fraction. We also flown LOAC under meteorological sounding balloons during those events to document the dust vertical distribution. Shorter integration time limits the sensitivity to large particles but their presence was confirmed in dust layers. Large particle were also occasionally observed during routine LOAC soundings at Aire-sur-l'Adour in southwestern France. The presence and persistence of a 'giant' mode at about 30 µm in diameter even after several days of transport contradicts calculations of particles sedimentation velocity. From an indirect evidence of the presence of charged particles derived from the LOAC measurements, we speculate that electrical forces might counteract gravitational settling of the coarse particles. More details can be found in the ChArMEx Special Issue (https://www.atmos-chem-phys.net/special_issue334.html; see Renard et al. papers).
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- 2018
41. Assessing the role of anthropogenic and biogenic sources on PM₁ over southern West Africa using aircraft measurements
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Brito, Joel, Freney, Evelyn, Dominutti, Pamela, Borbon, Agnes, Haslett, Sophie L., Batenburg, Anneke M., Colomb, Aurelie, Dupuy, Regis, Denjean, Cyrielle, Burnet, Frederic, Bourriane, Thierry, Deroubaix, Adrien, Sellegri, Karine, Borrmann, Stephan, Coe, Hugh, Flamant, Cyrille, Knippertz, Peter, and Schwarzenboeck, Alfons
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Earth sciences ,ddc:550 - Abstract
As part of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project, an airborne campaign was designed to measure a large range of atmospheric constituents, focusing on the effect of anthropogenic emissions on regional climate. The presented study details results of the French ATR42 research aircraft, which aimed to characterize gas-phase, aerosol and cloud properties in the region during the field campaign carried out in June/July 2016 in combination with the German Falcon 20 and the British Twin Otter aircraft. The aircraft flight paths covered large areas of Benin, Togo, Ghana and Côte d'Ivoire, focusing on emissions from large urban conurbations such as Abidjan, Accra and Lomé, as well as remote continental areas and the Gulf of Guinea. This paper focuses on aerosol particle measurements within the boundary layer ( 15 nm) of 735 cm−3 stp. Regarding submicron aerosol composition (considering non-refractory species and black carbon, BC), organic aerosol (OA) is the most abundant species contributing 53 %, followed by SO4 (27 %), NH4 (11 %), BC (6 %), NO3 (2 %) and minor contribution of Cl (
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- 2018
42. Assessing the role of anthropogenic and biogenic sources on PM1over southern West Africa using aircraft measurements
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Brito, Joel, Freney, Evelyn, Dominutti, Pamela, Borbon, Agnes, Haslett, Sophie L., Batenburg, Anneke M., Colomb, Aurelie, Dupuy, Regis, Denjean, Cyrielle, Burnet, Frederic, Bourriane, Thierry, Deroubaix, Adrien, Sellegri, Karine, Borrmann, Stephan, Coe, Hugh, Flamant, Cyrille, Knippertz, Peter, Schwarzenboeck, Alfons, Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomia, Geofísica e Ciências Atmosféricas [São Paulo] (IAG), Universidade de São Paulo = University of São Paulo (USP), Centre for Atmospheric Science [Manchester] (CAS), School of Earth and Environmental Sciences [Manchester] (SEES), University of Manchester [Manchester]-University of Manchester [Manchester], Max-Planck-Institut für Chemie (MPIC), Max-Planck-Gesellschaft, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology (KIT), European Union, European Project: 603502,EC:FP7:ENV,FP7-ENV-2013-two-stage,DACCIWA(2013), Universidade de São Paulo (USP), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)
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[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere - Abstract
International audience As part of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project, an airborne campaign was designed to measure a large range of atmospheric constituents, focusing on the effect of anthropogenic emissions on regional climate. The presented study details results of the French ATR42 research aircraft, which aimed to characterize gas-phase, aerosol and cloud properties in the region during the field campaign carried out in June/July 2016 in combination with the German Falcon 20 and the British Twin Otter aircraft. The aircraft flight paths covered large areas of Benin, Togo, Ghana and Ivory Coast, focusing on emissions from large urban conurbations such as Abidjan, Accra and Lomé, as well as remote continental areas and the Gulf of Guinea. This manuscript focuses on aerosol particle measurements within the boundary layer ( 15 nm) of 735 cm−3 stp. Regarding submicron aerosol composition (considering non-refractory species and Black Carbon, BC), organic aerosol (OA) is the most abundant species contributing 53 %, followed by SO4 (27 %), NH4 (11 %), BC (6 %), NO3 (2 %) and minor contribution of Cl (−3 stp. During measurements of urban pollution plumes, mainly focusing on the outflow of Abidjan, Accra and Lomé, pollutants are significantly enhanced (e.g. average concentration of CO of 176 ppb, and aerosol particle number concentration of 6500 cm−3 stp), as well as PM1 concentration (11.9 µg m−3 stp). Two classes of organic aerosols were estimated based from C-ToF-AMS: particulate organic nitrates (pON) and isoprene epoxydiols secondary organic aerosols (IEPOX-SOA). Both classes are usually associated with the formation of particulate matter through complex interactions of anthropogenic and biogenic sources. During DACCIWA, pON have a fairly small contribution to OA (around 5 %) and are more associated with long-range transport from central Africa than local formation. Conversely, IEPOX-SOA provides a significant contribution to OA (around 24 % and 28 % under background and in-plume conditions). Furthermore, the fractional contribution of IEPOX-SOA is largely unaffected by changes in the aerosol composition (particularly the SO4 concentration), which suggests that IEPOX-SOA concentration is mainly driven by pre-existing aerosol surface, instead of aerosol chemical properties. At times of large in-plume SO4 enhancements (above 5 µg m−3), the fractional contribution of IEPOX-SOA to OA increases above 50 %, suggesting only then a change in IEPOX-SOA controlling mechanism. It is important to note that IEPOX-SOA constitutes a lower limit to the contribution of biogenic OA, given that other processes (e.g. non-IEPOX isoprene, monoterpene SOA) are likely in the region. Given the significant contribution to aerosol concentration, it is crucial that such complex biogenic-anthropogenic interactions are taken into account in both present day and future scenario models of this fast-changing, highly sensitive region.
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- 2018
43. Light absorption properties of aerosols over Southern West Africa
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Denjean, Cyrielle, primary, Bourrianne, Thierry, additional, Burnet, Frederic, additional, Mallet, Marc, additional, Maury, Nicolas, additional, Colomb, Aurélie, additional, Dominutti, Pamela, additional, Brito, Joel, additional, Dupuy, Régis, additional, Sellegri, Karine, additional, Schwarzenboeck, Alfons, additional, Flamant, Cyrille, additional, and Knippertz, Peter, additional
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- 2019
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44. Aerosol influences on low-level clouds in the West African monsoon
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Taylor, Jonathan W., primary, Haslett, Sophie L., additional, Bower, Keith, additional, Flynn, Michael, additional, Crawford, Ian, additional, Dorsey, James, additional, Choularton, Tom, additional, Connolly, Paul J., additional, Hahn, Valerian, additional, Voigt, Christiane, additional, Sauer, Daniel, additional, Dupuy, Régis, additional, Brito, Joel, additional, Schwarzenboeck, Alfons, additional, Bourriane, Thierry, additional, Denjean, Cyrielle, additional, Rosenberg, Phil, additional, Flamant, Cyrille, additional, Lee, James D., additional, Vaughan, Adam R., additional, Hill, Peter G., additional, Brooks, Barbara, additional, Catoire, Valéry, additional, Knippertz, Peter, additional, and Coe, Hugh, additional
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- 2019
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45. Experimental study of the aerosol impact on fog microphysics
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Mazoyer, Marie, primary, Burnet, Frédéric, additional, Denjean, Cyrielle, additional, Roberts, Gregory C., additional, Haeffelin, Martial, additional, Dupont, Jean-Charles, additional, and Elias, Thierry, additional
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- 2019
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46. Impact of mineral dust on shortwave and longwave radiation: evaluation of different vertically resolved parameterizations in 1-D radiative transfer computations
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Granados-Muñoz, María José, primary, Sicard, Michael, additional, Román, Roberto, additional, Benavent-Oltra, Jose Antonio, additional, Barragán, Rubén, additional, Brogniez, Gerard, additional, Denjean, Cyrielle, additional, Mallet, Marc, additional, Formenti, Paola, additional, Torres, Benjamín, additional, and Alados-Arboledas, Lucas, additional
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- 2019
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47. Diurnal cycle of coastal anthropogenic pollutant transport over southern West Africa during the DACCIWA campaign
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Deroubaix, Adrien, primary, Menut, Laurent, additional, Flamant, Cyrille, additional, Brito, Joel, additional, Denjean, Cyrielle, additional, Dreiling, Volker, additional, Fink, Andreas, additional, Jambert, Corinne, additional, Kalthoff, Norbert, additional, Knippertz, Peter, additional, Ladkin, Russ, additional, Mailler, Sylvain, additional, Maranan, Marlon, additional, Pacifico, Federica, additional, Piguet, Bruno, additional, Siour, Guillaume, additional, and Turquety, Solène, additional
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- 2019
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48. Closure of In-Situ Measured Aerosol Backscattering and Extinction Coefficients with Lidar Accounting for Relative Humidity.
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Düsing, Sebastian, Ansmann, Albert, Baars, Holger, Corbin, Joel C., Denjean, Cyrielle, Gysel-Beer, Martin, Müller, Thomas, Poulain, Laurent, Siebert, Holger, Spindler, Gerald, Tuch, Thomas, Wehner, Birgit, and Wiedensohler, Alfred
- Abstract
Aerosol particles contribute to the climate forcing through their optical properties. Measuring these aerosol optical properties is still challenging, especially considering the hygroscopic growth of aerosol particles, which alters their optical properties. Lidar and in-situ techniques can derive a variety of aerosol optical properties, like aerosol particle light extinction, backscattering, and absorption. But these techniques are subject to some limitations and uncertainties. Within this study, we compared with Mie-theory modeled aerosol optical properties with direct measurements. At dried state they were with airborne and ground-based in-situ measurements; at ambient state with lidar estimates. Also, we examined the dependence of the aerosol particle light extinction-to-backscatter ratio, also lidar ratio (LR), to relative humidity. The used model was fed with measured physicochemical aerosol properties and ambient atmospheric conditions. The model considered aerosol particles in an internal core-shell mixing state with constant volume fractions of the aerosol components over the entire observed aerosol particle size-range. The underlying set of measurements was conducted near the measurement site Melpitz, Germany, during two campaigns in summer, 2015, and winter, 2017, and represent Central European background aerosol conditions. Two airborne payloads deployed on a helicopter and a balloon provided measurements of microphysical and aerosol optical properties and were complemented by the polarization Raman lidar system Polly
XT as well as by a holistic set of microphysical, chemical and optical aerosol measurements derived at ground level. The calculated aerosol optical aerosol properties agreed within 13% (3%) with the ground-based in-situ measured aerosol optical properties at a dried state (relative humidity below 40%) in terms of scattering at 450 nm wavelength during the winter (summer) campaign. The model also represented the aerosol particle light absorption at 637 nm within 8% (18%) during the winter (summer) campaign and agreed within 13% with the airborne in-situ aerosol particle light extinction measurements during summer. During winter, in a comparatively clean case with equivalent black carbon mass-concentrations of around 0.2 µg m-3 the modeled airborne measurement-based aerosol particle light absorption, was up to 32-37% larger than the measured values during a relatively clean period. However, during a high polluted case, with an equivalent black carbon mass concentration of around 4 µg m-3 , the modeled aerosol particle light absorption coefficient was, depending on the wavelength, 13-32% lower than the measured values. Spread and magnitude of the disagreement highlighted the importance of the aerosol mixing state used within the model, the requirement of the inclusion of brown carbon, and a wavelength-dependent complex refractive index of black and brown carbon when such kind of model is used to validate aerosol particle light absorption coefficient estimates of, e.g., lidar systems. Besides dried state comparisons, ambient modeled aerosol particle light extinction, as well as aerosol particle light backscattering, were compared with lidar estimates of these measures. During summer, on average, for four of the twelve conducted measurement flights, the model calculated lower aerosol particle light extinction (up to 29% lower) as well as backscattering (up to 32% lower) than derived with the lidar. In winter, the modeled aerosol particle light extinction coefficient was 17%-41% lower, the aerosol particle light backscattering coefficient 14%-42% lower than the lidar estimates. For both, the winter and summer cases, the Mie-model estimated reasonable extinction-to-backscatter ratios (LR). Measurement-based Mie-modeling showed evidence of the dependence of the LR on relative humidity (RH). With this result, we presented a fit for lidar wavelengths of 355, 532, and 1064 nm with an underlying equation of f[sub LR](TH, γ(λ)) = f[sub LR] (RH = 0, λ) x (1 - RH)-γ(λ) and estimates of γ(355 nm) = 0.29 (±0.01), γ(532 nm) = 0.48 (±0.01), and γ(1064 nm) = 0.31 (±0.01). However, further measurements are required to entangle the behavior of the LR with respect to different aerosol types, to set up a climatology, and to assess the influence of the aerosol mixing state. This comprehensive study combining airborne and ground-based in-situ and remote sensing measurements, which simulated multiple aerosol optical coefficients in the ambient and dry state, is with its complexity unique of its kind. [ABSTRACT FROM AUTHOR]- Published
- 2021
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49. A mini backscatter lidar for airborne measurements in the framework of DACCIWA
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Chazette, Patrick, Totems, Julien, Flamant, Cyrille, Shang, Xiaoxia, Denjean, Cyrielle, Meynadier, Remi, Perrin, Thierry, Laurens, Marc, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), SPACE - LATMOS, Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE), Centre National de la Recherche Scientifique (CNRS)-Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, and Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
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[SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology - Abstract
International audience; During the international campaign of the European program Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA), investigating the relationship between weather, climate and air pollution in southern West Africa, a mini backscatter lidar was embedded on the French research aircraft (ATR42) of the Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE). This implementation was made possible thanks to the support of the Centre National d'Etude Spatial (CNES), with the aim of assessing the relative relevance of airborne or spaceborne (e.g. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations, CALIPSO) remote sensing instruments. The lidar complemented the various in-situ observations carried out on the plane, by identifying the aerosol layers in the atmospheric column below the aircraft, and bringing strong constraints for the validation of other measurements. The field campaign took place from 27 to 16 July 2016 from Lomé, Togo. The aircraft conducted flights between 1 km and 5 km above the mean sea level (amsl), allowing the coupling of in situ and remote sensing data to assess the properties of the aerosol layers. Aerosol plumes of different origins were identified using the coupling between the lidar cross-polarized channels, satellite observations and a set of back trajectories analyses. During several flights, depolarizing aerosol layers from the northeast were observed between 2.5 and 4 km amsl, which highlight the significant contribution of dust-like particles to the aerosol load in the coastal region. Conversely, air masses originating from the east-southeast were loaded with a mixing of biomass burning and pollution aerosols. The former originated from Central Africa and the latter from human activities in and around large cities (Lomé). The flight sampling strategy and related lidar investigations will be presented and discussed.
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- 2017
50. Impact of long-range transport pollution on aerosol properties over West Africa: observations during the DACCIWA airborne campaign
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Denjean, Cyrielle, Bourrianne, Thierry, Burnet, Frédéric, Deroubaix, Adrien, Brito, Joel, Dupuy, Régis, Colomb, Aurélie, Schwarzenboeck, Alfons, Sellegri, Karine, Chazette, Patrick, Duplissy, Jonathan, Flamant, Cyrille, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de Météorologie Physique (LaMP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Department of Physics [Helsinki], Falculty of Science [Helsinki], University of Helsinki-University of Helsinki, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, and Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
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[SDE]Environmental Sciences - Abstract
International audience; Southern West Africa (SWA) is a region highly vulnerable to climate change. Emissions of anthropogenic pollution have increased substantially over the past decades in the region and are projected to keep increasing. The region is also strongly impacted by important natural pollution from distant locations. Biomass burning mainly from vegetation fires in Central Africa and mineral dust from the Saharan and Sahel-Sudan regions are advected by winds to the SWA region especially in summer. Both biomass burning and mineral dust aerosols scatter and absorb solar radiation and are able to significantly modify the regional radiative budget. Presently, the potential radiative impact of dust and biomass burning particles on SWA is unclear due to inadequate data information on the aerosols properties and vertical distribution. In the framework of the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) project, an unprecedented field campaign took place in summer 2016 in West Africa. The ATR-42 research aircraft operated by SAFIRE performed twenty flights to sample the local air pollution from maritime traffic and coastal megacities, as well as regional pollution from biomass burning and desert dust. The aircraft was equipped with state of the art in situ instrumentation to measure the aerosol optical properties (CAPS, nephelometer, PSAP), the aerosol size distribution (SMPS, GRIMM, USHAS, PCASP, FSSP) and the aerosol chemical composition (SP2, AMS). A mini backscattered lidar system provided additional measurements of the aerosol vertical structure and the aerosol optical properties such as the particulate depolarization ratio. The CHIMERE chemistry and transport model has been used to characterize the source area and the long-range transport of dust and biomass burning plumes. Here, we investigate the aerosol microphysical, chemical and optical properties of biomass burning and dust aerosols transported in SWA. In particular the following questions will be addressed: (i) what are the differences in the aerosol optical properties and vertical distribution in SWA during intense biomass burning and dust events ? (ii) what is the range of mass extinction efficiencies and single scattering albedo for these events and what explains their variability ? (iii) what is the range in aerosol size distribution in biomass burning and dust layers and how does this vary with plume age ?
- Published
- 2017
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