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You searched for subject:(sea salt aerosols). Showing records 1 – 3 of 3 total matches.

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1. Hoarau, Thomas. Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study.

Degree: Docteur es, Physique de l'atmosphère, 2018, La Réunion

La prévision de l'intensité des cyclones tropicaux est aujourd'hui un enjeu scientifique majeur. Parmi de nombreux facteurs multi-échelle, l'impact de la microphysique nuageuse et des aérosols sur les variations d'intensité a été récemment mis en évidence. Cette problématique a motivé l'évaluation du schéma microphysique à 2-moments LIMA en milieu tropical et le développement d'un couplage avec le schéma d'aérosols ORILAM au sein du modèle atmosphérique Meso-NH. L'intérêt de ce développement numérique est d'inclure l'émission des aérosols marins en fonction des vents cycloniques et des paramètres océaniques. L'application de ce couplage aérosols-microphysique à la simulation du cyclone tropical Dumile (2013) montre que le modèle couplé tend à améliorer la représentation de l'intensité, la trajectoire, la structure microphysique du cyclone tropical et les précipitations associées, en comparaison avec les observations. La production secondaire des cristaux de glace est également un thème de recherche actif en microphysique nuageuse. Ainsi, une paramétrisation du processus de rupture collisionnelle de la glace a été implémentée dans le schéma microphysique LIMA. L'impact de ce processus a été testé sur le développement d'un orage des moyennes latitudes et sur le cyclone tropical Dumile. Les deux cas d'étude ont des réponses similaires vis-à-vis de ce processus : une augmentation de la concentration et de la masse des cristaux de glace et une diminution des cumuls de précipitations. La poursuite de ces travaux pourrait permettre de déterminer si ce processus de formation secondaire peut améliorer la modélisation de la couverture cirriforme des cyclones tropicaux.

Intensity forecast of tropical cyclones is a major scientific issue. Among many factors, the impact of cloud microphysics and aerosols on intensity variations has been recently underlined. This issue motivated the evaluation of the 2-moment microphysical scheme LIMA in a tropical context and the development of a coupling with the aerosol scheme ORILAM into the atmospheric model Meso-NH. The interest of this numerical development is to represent the emission of sea salt aerosols depending on cyclonic winds and oceanic parameters. The application of this aerosols-microphysics coupling to the simulation of tropical cyclone Dumile (2013) shows that the coupled model tends to improve the representation of the intensity, the track, the microphysical structure of the tropical cyclone and the associated precipitation, when comparing with observations. The secondary production of ice crystals is also an active research topic in cloud microphysics. A parameterization of the collisional ice break-up process is thus implemented into the microphysical scheme LIMA. The impact of this process has been analyzed on a mid-latitude storm and on tropical cyclone Dumile. Both case studies display similar results regarding this process: an increase of ice crystals concentration and mass, and a decrease of precipitation. The continuation of this work could allow to determine if…

Advisors/Committee Members: Barthe, Christelle (thesis director), Bousquet, Olivier (thesis director).

Subjects/Keywords: Cyclone tropical; Microphysique nuageuse; Sels marins; Modélisation; Prévision d'intensité; Tropical cyclone; Cloud microphysics; Sea salt aerosols; Modelling; Intensity forecast

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hoarau, T. (2018). Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study. (Doctoral Dissertation). La Réunion. Retrieved from http://www.theses.fr/2018LARE0012

Chicago Manual of Style (16th Edition):

Hoarau, Thomas. “Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study.” 2018. Doctoral Dissertation, La Réunion. Accessed July 09, 2020. http://www.theses.fr/2018LARE0012.

MLA Handbook (7th Edition):

Hoarau, Thomas. “Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study.” 2018. Web. 09 Jul 2020.

Vancouver:

Hoarau T. Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study. [Internet] [Doctoral dissertation]. La Réunion; 2018. [cited 2020 Jul 09]. Available from: http://www.theses.fr/2018LARE0012.

Council of Science Editors:

Hoarau T. Couplage aérosols-microphysique pour la simulation des cyclones tropicaux : Cas du cyclone Dumile (2013) : Aerosols-microphysics coupling for tropical cyclone modelling : Tropical cyclone Dumile (2013) case study. [Doctoral Dissertation]. La Réunion; 2018. Available from: http://www.theses.fr/2018LARE0012


Queensland University of Technology

2. Johnson, Graham Richard. The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis.

Degree: 2005, Queensland University of Technology

Marine aerosols have attracted increasing attention over the past 15 years because of their potential significance for global climate modelling. The size distribution of these aerosols extends from super-micrometer sea salt mode particles down through 150 nm accumulation mode particles, 40 nm Aitken mode particles and nucleation mode particles which extend from 25 nm right down to clusters of a few molecules. The process by which the submicrometer modes form and grow and their composition have remained topics of debate throughout this time in large part because of the difficulties associated with determining their composition and relating it to proposed models of the formation process. The work compared the modality of marine aerosol influencing the South-east-Queensland region with that of other environmental aerosols in the region. The aerosol was found to be consistent with marine aerosols observed elsewhere with concentrations below 1000 cm-3 and frequently exhibiting the distinct bimodal structure associated with cloud processing, consisting of an Aitken mode at approximately 40 nm, an accumulation mode in the range 100-200 nm and a coarse mode attributed to sea salt between 600 and 1200 nm. This work included the development of two new techniques for aerosol research. The first technique measures aerosol density using a combination of aerosol size distribution and gravimetric mass concentration measurements. This technique was used to measure the density of a number of submicrometer aerosols including laboratory generated NaCl aerosol and ambient aerosol. The densities for the laboratory generated aerosols were found to be similar to those for the bulk materials used to produce them. The technique, extended to super-micrometer particle size range may find application in ambient aerosol research where it could be used to discriminate between periods when the aerosol is dominated by NaCl and periods when the density is more representative of crustal material or sulfates. The technique may also prove useful in laboratory or industrial settings for investigating particle density or in case where the composition is known, morphology and porosity. The second technique developed, integrates the existing physicochemical techniques of volatilisation and hygroscopic growth analysis to investigate particle composition in terms of both the volatilisation temperatures of the chemical constituents and their contribution to particle hygroscopic behaviour. The resulting volatilisation and humidification tandem differential mobility analyser or VH-TDMA, has proven to be a valuable research tool which is being used in ongoing research. Findings of investigations relating the composition of the submicrometer marine aerosol modes to candidate models for their formation are presented. Sea salt was not found in the numerically dominant particle type in coastal nucleation mode or marine Aitken and accumulation modes examined on the Southeast…

Subjects/Keywords: Aerosol size distribution; modality; environmental aerosols; marine aerosols; aerosol density; ambient aerosol; VH-TDMA; particle hygroscopic growth; volatility; iodine oxides; non sea salt sulfate; sea salt aerosols; coastal aerosol; marine biota; algae; photolysis; photochemical; thermal decomposition; volatilisation and humidification tandem differential mobility analyser; ultra fine particles.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Johnson, G. R. (2005). The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/16117/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Johnson, Graham Richard. “The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis.” 2005. Thesis, Queensland University of Technology. Accessed July 09, 2020. https://eprints.qut.edu.au/16117/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Johnson, Graham Richard. “The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis.” 2005. Web. 09 Jul 2020.

Vancouver:

Johnson GR. The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis. [Internet] [Thesis]. Queensland University of Technology; 2005. [cited 2020 Jul 09]. Available from: https://eprints.qut.edu.au/16117/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Johnson GR. The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis. [Thesis]. Queensland University of Technology; 2005. Available from: https://eprints.qut.edu.au/16117/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Nuaaman, Ibraheem M. Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California.

Degree: PhD, Chemistry, 2015, York University

This dissertation is of two parts. In the first part, carbonyls were measured in Ridgetown, Ontario using an automated HPLC-DNPH system during the BAQS-Met study in 2007. Median concentrations for formaldehyde, acetaldehyde, acetone, propanal, MEK and butanal were observed to be 1.5, 0.67, 1.9, 0.072, 0.22 and 0.041 ppb respectively. The highest carbonyl concentrations were observed with trans-boundary transport associated with airmasses that passed over Michigan and Illinois and could have originated from the Ohio Valley. Local ozone sensitivity was established using the HCHO/NO2 ratio and this area was found to be sensitive to both VOCs and NOx. Carbonyls accounted for 35% of O3 formation estimated using the MIR scale. Lake breeze events had no significant impact on carbonyl concentrations in this location. In the second part of this dissertation, aerosol concentrations and composition were obtained along the coast of California using a High-Resolution Time-of-Flight aerosol mass spectrometer (HR-AMS) onboard RV Atlantis during CalNex in 2010. Measured submicron aerosols were dominated by particulate sulfate and particulate organic matter (pOM), which accounted for 86% of all measured submicron aerosol mass. High aerosol concentrations were associated with land breezes from polluted cities while low concentrations were observed with sea breezes. For the first time, a method is proposed to establish non-refractory particulate chloride (NR p-Cl) in ambient air that is enriched with sea salt chloride. This method involves the subtraction of refractory chloride signal (RF HxCl+), which was estimated using the HxCl+ (total chloride signal) to Na35Cl+ ratio in artificially generated sea spray aerosols. Also for the first time, a method is proposed to determine percentage chloride depletion in ambient aerosols using HR-AMS measurements of Na+ and Na35Cl+. Using this proposed method, study-wide median chloride depletion in submicron aerosols was determined to be 78%. For NR p-Cl, increasing concentrations were observed with increasing RH and pH and decreasing temperature. Finally, pOM in sea spray aerosols was observed to be dominated by hydrocarbons (55%) and oxygenated hydrocarbon classes (37%); this pOM was found to be positively correlated with seawater DMS. Advisors/Committee Members: McLaren, Robert (advisor).

Subjects/Keywords: Atmospheric chemistry; Atmospheric sciences; Chemistry; Atmospheric chemistry; Troposphere; Aerosols; AMS; HR-AMS; HR-ToF-AMS; Refractory; Non-refractory; Chloride; Sulfate; Nitrate; Ammonium; Sea salt; Na35Cl+; Lake breeze; Land breeze; Sea breeze; Sea spray; Organics; Chloride depletion; Method; Carbonyls; Interference; Submicron; Particulate; Particulate matter; pH; Temperature; Relative humidity; Formaldehyde; Acetaldehyde; Acetone; Propanal; Butanal; MEK; BAQS-Met; CalNex; California; Ontario; DNPH; HPLC; Trans-boundary transport; Na+; Mass spectrum; Chlorine; Nitryl chloride; Anthropogenic; Biogenic; Primary; Secondary; Pollutant; Aerosol mass spectrometer; Diurnal; HCHO/NO2; Ozone sensitivity; VOC; OVOC; Sea sweep

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Nuaaman, I. M. (2015). Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California. (Doctoral Dissertation). York University. Retrieved from http://hdl.handle.net/10315/30094

Chicago Manual of Style (16th Edition):

Nuaaman, Ibraheem M. “Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California.” 2015. Doctoral Dissertation, York University. Accessed July 09, 2020. http://hdl.handle.net/10315/30094.

MLA Handbook (7th Edition):

Nuaaman, Ibraheem M. “Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California.” 2015. Web. 09 Jul 2020.

Vancouver:

Nuaaman IM. Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California. [Internet] [Doctoral dissertation]. York University; 2015. [cited 2020 Jul 09]. Available from: http://hdl.handle.net/10315/30094.

Council of Science Editors:

Nuaaman IM. Investigation of Air Pollutants Near the Great Lakes in Ontario and Along the Coast of California. [Doctoral Dissertation]. York University; 2015. Available from: http://hdl.handle.net/10315/30094

.