1,016 results on '"Wiedensohler, Alfred"'
Search Results
402. Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)
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Birmili, Wolfram, primary, Weinhold, Kay, additional, Rasch, Fabian, additional, Sonntag, André, additional, Sun, Jia, additional, Merkel, Maik, additional, Wiedensohler, Alfred, additional, Bastian, Susanne, additional, Schladitz, Alexander, additional, Löschau, Gunter, additional, Cyrys, Josef, additional, Pitz, Mike, additional, Gu, Jianwei, additional, Kusch, Thomas, additional, Flentje, Harald, additional, Quass, Ulrich, additional, Kaminski, Heinz, additional, Kuhlbusch, Thomas A. J., additional, Meinhardt, Frank, additional, Schwerin, Andreas, additional, Bath, Olaf, additional, Ries, Ludwig, additional, Gerwig, Holger, additional, Wirtz, Klaus, additional, and Fiebig, Markus, additional
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- 2016
- Full Text
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403. Variation of CCN activity during new particle formation events in the North China Plain
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Ma, Nan, primary, Zhao, Chunsheng, additional, Tao, Jiangchuan, additional, Wu, Zhijun, additional, Kecorius, Simonas, additional, Wang, Zhibin, additional, Größ, Johannes, additional, Liu, Hongjian, additional, Bian, Yuxuan, additional, Kuang, Ye, additional, Teich, Monique, additional, Spindler, Gerald, additional, Müller, Konrad, additional, van Pinxteren, Dominik, additional, Herrmann, Hartmut, additional, Hu, Min, additional, and Wiedensohler, Alfred, additional
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- 2016
- Full Text
- View/download PDF
404. Evidence for ambient dark aqueous SOA formation in the Po Valley, Italy
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Sullivan, Amy P., primary, Hodas, Natasha, additional, Turpin, Barbara J., additional, Skog, Kate, additional, Keutsch, Frank N., additional, Gilardoni, Stefania, additional, Paglione, Marco, additional, Rinaldi, Matteo, additional, Decesari, Stefano, additional, Facchini, Maria Cristina, additional, Poulain, Laurent, additional, Herrmann, Hartmut, additional, Wiedensohler, Alfred, additional, Nemitz, Eiko, additional, Twigg, Marsailidh M., additional, and Collett Jr., Jeffrey L., additional
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- 2016
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- View/download PDF
405. Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns
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Rosati, Bernadette, primary, Gysel, Martin, additional, Rubach, Florian, additional, Mentel, Thomas F., additional, Goger, Brigitta, additional, Poulain, Laurent, additional, Schlag, Patrick, additional, Miettinen, Pasi, additional, Pajunoja, Aki, additional, Virtanen, Annele, additional, Klein Baltink, Henk, additional, Henzing, J. S. Bas, additional, Größ, Johannes, additional, Gobbi, Gian Paolo, additional, Wiedensohler, Alfred, additional, Kiendler-Scharr, Astrid, additional, Decesari, Stefano, additional, Facchini, Maria Cristina, additional, Weingartner, Ernest, additional, and Baltensperger, Urs, additional
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- 2016
- Full Text
- View/download PDF
406. Supplementary material to "Significant concentrations of nitryl chloride sustained in the morning: Investigations of the causes and impacts on ozone production in a polluted region of northern China"
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Tham, Yee Jun, primary, Wang, Zhe, additional, Li, Qinyi, additional, Yun, Hui, additional, Wang, Weihao, additional, Wang, Xinfeng, additional, Xue, Likun, additional, Lu, Keding, additional, Ma, Nan, additional, Bohn, Birger, additional, Li, Xin, additional, Kecorius, Simonas, additional, Größ, Johannes, additional, Shao, Min, additional, Wiedensohler, Alfred, additional, Zhang, Yuanhang, additional, and Wang, Tao, additional
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- 2016
- Full Text
- View/download PDF
407. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC
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Hermann, Markus, primary, Weigelt, Andreas, additional, Assmann, Denise, additional, Pfeifer, Sascha, additional, Müller, Thomas, additional, Conrath, Thomas, additional, Voigtländer, Jens, additional, Heintzenberg, Jost, additional, Wiedensohler, Alfred, additional, Martinsson, Bengt G., additional, Deshler, Terry, additional, Brenninkmeijer, Carl A. M., additional, and Zahn, Andreas, additional
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- 2016
- Full Text
- View/download PDF
408. Sea salt emission, transportation and influence on nitrate simulation: a case study in Europe
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Chen, Ying, primary, Cheng, Yafang, additional, Ma, Nan, additional, Wolke, Ralf, additional, Nordmann, Stephan, additional, Schüttauf, Stephanie, additional, Ran, Liang, additional, Wehner, Birgit, additional, Birmili, Wolfram, additional, Denier van der Gon, Hugo A. C., additional, Mu, Qing, additional, Barthel, Stefan, additional, Spindler, Gerald, additional, Stieger, Bastian, additional, Müller, Konrad, additional, Zheng, Guang-Jie, additional, Pöschl, Ulrich, additional, Su, Hang, additional, and Wiedensohler, Alfred, additional
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- 2016
- Full Text
- View/download PDF
409. Supplementary material to "Sea salt emission, transportation and influence on nitrate simulation: a case study in Europe"
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Chen, Ying, primary, Cheng, Yafang, additional, Ma, Nan, additional, Wolke, Ralf, additional, Nordmann, Stephan, additional, Schüttauf, Stephanie, additional, Ran, Liang, additional, Wehner, Birgit, additional, Birmili, Wolfram, additional, Denier van der Gon, Hugo A. C., additional, Mu, Qing, additional, Barthel, Stefan, additional, Spindler, Gerald, additional, Stieger, Bastian, additional, Müller, Konrad, additional, Zheng, Guang-Jie, additional, Pöschl, Ulrich, additional, Su, Hang, additional, and Wiedensohler, Alfred, additional
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- 2016
- Full Text
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410. Measuring the morphology and density of internally mixed black carbon with SP2 and VTDMA: new insight into the absorption enhancement of black carbon in the atmosphere
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Zhang, Yuxuan, primary, Zhang, Qiang, additional, Cheng, Yafang, additional, Su, Hang, additional, Kecorius, Simonas, additional, Wang, Zhibin, additional, Wu, Zhijun, additional, Hu, Min, additional, Zhu, Tong, additional, Wiedensohler, Alfred, additional, and He, Kebin, additional
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- 2016
- Full Text
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411. Studying the vertical aerosol extinction coefficient by comparing in situ airborne data and elastic backscatter lidar
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Rosati, Bernadette, primary, Herrmann, Erik, additional, Bucci, Silvia, additional, Fierli, Federico, additional, Cairo, Francesco, additional, Gysel, Martin, additional, Tillmann, Ralf, additional, Größ, Johannes, additional, Gobbi, Gian Paolo, additional, Di Liberto, Luca, additional, Di Donfrancesco, Guido, additional, Wiedensohler, Alfred, additional, Weingartner, Ernest, additional, Virtanen, Annele, additional, Mentel, Thomas F., additional, and Baltensperger, Urs, additional
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- 2016
- Full Text
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412. Intercomparison of 15 aerodynamic particle size spectrometers (APS 3321): uncertainties in particle sizing and number size distribution
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Pfeifer, Sascha, primary, Müller, Thomas, additional, Weinhold, Kay, additional, Zikova, Nadezda, additional, Martins dos Santos, Sebastiao, additional, Marinoni, Angela, additional, Bischof, Oliver F., additional, Kykal, Carsten, additional, Ries, Ludwig, additional, Meinhardt, Frank, additional, Aalto, Pasi, additional, Mihalopoulos, Nikolaos, additional, and Wiedensohler, Alfred, additional
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- 2016
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413. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris) during the MEGAPOLI summer and winter campaigns
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Fountoukis, Christos, primary, Megaritis, Athanasios G., additional, Skyllakou, Ksakousti, additional, Charalampidis, Panagiotis E., additional, Denier van der Gon, Hugo A. C., additional, Crippa, Monica, additional, Prévôt, André S. H., additional, Fachinger, Friederike, additional, Wiedensohler, Alfred, additional, Pilinis, Christodoulos, additional, and Pandis, Spyros N., additional
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- 2016
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414. Properties of cloud condensation nuclei (CCN) in the trade wind marine boundary layer of the western North Atlantic
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Kristensen, Thomas B., primary, Müller, Thomas, additional, Kandler, Konrad, additional, Benker, Nathalie, additional, Hartmann, Markus, additional, Prospero, Joseph M., additional, Wiedensohler, Alfred, additional, and Stratmann, Frank, additional
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- 2016
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415. Evaluation of the size segregation of elemental carbon (EC) emission in Europe: influence on the simulation of EC long-range transportation
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Chen, Ying, primary, Cheng, Ya-Fang, additional, Nordmann, Stephan, additional, Birmili, Wolfram, additional, Denier van der Gon, Hugo A. C., additional, Ma, Nan, additional, Wolke, Ralf, additional, Wehner, Birgit, additional, Sun, Jia, additional, Spindler, Gerald, additional, Mu, Qing, additional, Pöschl, Ulrich, additional, Su, Hang, additional, and Wiedensohler, Alfred, additional
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- 2016
- Full Text
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416. Dependence of CPC cut-off diameter on particle morphology and other factors
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Tuch, Thomas, primary, Weinhold, Kay, additional, Merkel, Maik, additional, Nowak, Andreas, additional, Klein, Tobias, additional, Quincey, Paul, additional, Stolzenburg, Mark, additional, and Wiedensohler, Alfred, additional
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- 2016
- Full Text
- View/download PDF
417. Significant increase of aerosol number concentrations in air masses crossing a densely trafficked sea area
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Kecorius, Simonas, primary, Kivekäs, Niku, additional, Kristensson, Adam, additional, Tuch, Thomas, additional, Covert, David S., additional, Birmili, Wolfram, additional, Lihavainen, Heikki, additional, Hyvärinen, Antti-Pekka, additional, Martinsson, Johan, additional, Sporre, Moa K., additional, Swietlicki, Erik, additional, Wiedensohler, Alfred, additional, and Ulevicius, Vidmantas, additional
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- 2016
- Full Text
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418. An optical particle counter for the regular application onboard a passenger aircraft: instrument modification, characterization and results from the first year of operation
- Author
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Hermann, Markus, Wiedensohler, Alfred, Brenninkmeijer, Carl A.M., Universität Leipzig, Weigelt, Andreas, Hermann, Markus, Wiedensohler, Alfred, Brenninkmeijer, Carl A.M., Universität Leipzig, and Weigelt, Andreas
- Abstract
To understand the contribution of aerosol particles to radiative forcing and heterogeneous chemical processes in the upper troposphere and lowermost stratosphere (UT/LMS), the knowledge of the particle size distribution is mandatory. Unfortunately, measurements in the UT/LMS are costly. Research aircrafts are expensive and thus their application is limited in time and space. Satellite remote sensing measurements provide a good temporal and spatial (horizontal) coverage, but only a limited vertical resolution and currently cannot resolve the particle size distribution. Therefore, within this thesis an optical particle counter (OPC) unit was modified for the application onboard a passenger long-haul aircraft within the CARIBIC project (www.caribic-atmospheric.com). The CARIBIC OPC unit provides regular and cost-efficient particle size distribution measurements of accumulation mode particles in the UT/LMS. In April 2010, the new OPC unit was installed for the first time onboard the Lufthansa Airbus A340 600 (D-AIHE) for the measurement of the volcanic ash cloud from the Eyjafjallajökull eruption (April to May 2010). Since June 2010 the OPC unit measures on usually four intercontinental flights per month the UT/LMS particle size distribution in the particle size range 125 to 1300 nm particle diameter. As the data acquisition stores the scattering raw signal and all housekeeping data as well, during the post flight data analysis the temporal- and size channel resolution can be flexible set. Within this work the data were analyzed with 32 size channels and 300 seconds. As aircraft-borne measurements are always time-consuming, the development of the OPC unit and the analysis routine, as well as its characterization and certification took more than two thirds of the total working time of this thesis. Therefore, the analysis of the data is limited to the first year of regular measurements until May 2011. Nevertheless, this dataset is sufficient to demonstrate the scientific, Um die Rolle von Aerosolpartikeln beim Strahlungsantrieb und der heterogenen chemischen Prozessen in der oberen Troposphäre und untersten Stratosphäre (OT/US) verstehen zu können, ist es unabdingbar die Partikelgrößenverteilung zu kennen. Messungen der Partikelgrößenverteilung in dieser Region sind allerdings aufwendig. Der Einsatz von Forschungsflugzeugen ist teuer und deshalb zeitlich und räumlich nur begrenzt. Satellitenmessungen bieten zwar eine gute zeitliche und räumliche (horizontal) Abdeckung, aber nur eine begrenzte vertikale Auflösung. Weiterhin können bisherige Satellitenmessungen die Partikelgrößenverteilung nicht auflösen. Im Rahmen dieser Arbeit wurde deshalb ein optischer Partikelzähler (OPC) Messeinschub für den Einsatz an Bord eines Langstrecken-Passagierflugzeugs aufgebaut (CARIBIC Projekt, www.caribic-atmospheric.com). Mit diesem Messeinschub kann regelmäßig und kosteneffizient die Partikelgrößenverteilung des Akkumulationsmodes in der OT/US gemessen werden. Im April 2010 wurde der neue OPC Einschub erstmals an Bord des Lufthansa Airbus A340-600 (D-AIHE) installiert um die Vulkanasche der Eyjafjallajökull Eruption (April bis Mai 2010) zu messen. Seit Juni 2010 misst der OPC Einschub auf durchschnittlich vier Interkontinentalflügen pro Monat die Partikelgrößenverteilung der OT/US im Größenbereich zwischen 125 und 1300 nm Partikeldurchmesser. Während des Fluges speichert die Datenerfassung alle Rohsignale ab und ermöglicht dadurch eine nutzerspezifische Datenauswertung nach dem Flug (z. B. Anzahl der Größenkanäle oder Zeitauflösung). Im Rahmen dieser Arbeit wurden die Daten mit 32 Größenkanälen und 300 Sekunden analysiert. Da fluggetragene Messungen immer sehr aufwendig sind, beanspruchte die Entwicklung des OPC Einschubs und des Analysealgorithmus, sowie die Charakterisierung und Zertifizierung mehr als zwei Drittel der Gesamtarbeitszeit dieser Arbeit. Daher ist die Analyse der Messdaten auf das erste Jahr der regulären Messungen bis Mai 2011 besch
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- 2015
419. An optical particle counter for the regular application onboard a passenger aircraft: instrument modification, characterization and results from the first year of operation
- Author
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Wiedensohler, Alfred, Brenninkmeijer, Carl A.M., Universität Leipzig, Weigelt, Andreas, Wiedensohler, Alfred, Brenninkmeijer, Carl A.M., Universität Leipzig, and Weigelt, Andreas
- Abstract
To understand the contribution of aerosol particles to radiative forcing and heterogeneous chemical processes in the upper troposphere and lowermost stratosphere (UT/LMS), the knowledge of the particle size distribution is mandatory. Unfortunately, measurements in the UT/LMS are costly. Research aircrafts are expensive and thus their application is limited in time and space. Satellite remote sensing measurements provide a good temporal and spatial (horizontal) coverage, but only a limited vertical resolution and currently cannot resolve the particle size distribution. Therefore, within this thesis an optical particle counter (OPC) unit was modified for the application onboard a passenger long-haul aircraft within the CARIBIC project (www.caribic-atmospheric.com). The CARIBIC OPC unit provides regular and cost-efficient particle size distribution measurements of accumulation mode particles in the UT/LMS. In April 2010, the new OPC unit was installed for the first time onboard the Lufthansa Airbus A340 600 (D-AIHE) for the measurement of the volcanic ash cloud from the Eyjafjallajökull eruption (April to May 2010). Since June 2010 the OPC unit measures on usually four intercontinental flights per month the UT/LMS particle size distribution in the particle size range 125 to 1300 nm particle diameter. As the data acquisition stores the scattering raw signal and all housekeeping data as well, during the post flight data analysis the temporal- and size channel resolution can be flexible set. Within this work the data were analyzed with 32 size channels and 300 seconds. As aircraft-borne measurements are always time-consuming, the development of the OPC unit and the analysis routine, as well as its characterization and certification took more than two thirds of the total working time of this thesis. Therefore, the analysis of the data is limited to the first year of regular measurements until May 2011. Nevertheless, this dataset is sufficient to demonstrate the scientific, Um die Rolle von Aerosolpartikeln beim Strahlungsantrieb und der heterogenen chemischen Prozessen in der oberen Troposphäre und untersten Stratosphäre (OT/US) verstehen zu können, ist es unabdingbar die Partikelgrößenverteilung zu kennen. Messungen der Partikelgrößenverteilung in dieser Region sind allerdings aufwendig. Der Einsatz von Forschungsflugzeugen ist teuer und deshalb zeitlich und räumlich nur begrenzt. Satellitenmessungen bieten zwar eine gute zeitliche und räumliche (horizontal) Abdeckung, aber nur eine begrenzte vertikale Auflösung. Weiterhin können bisherige Satellitenmessungen die Partikelgrößenverteilung nicht auflösen. Im Rahmen dieser Arbeit wurde deshalb ein optischer Partikelzähler (OPC) Messeinschub für den Einsatz an Bord eines Langstrecken-Passagierflugzeugs aufgebaut (CARIBIC Projekt, www.caribic-atmospheric.com). Mit diesem Messeinschub kann regelmäßig und kosteneffizient die Partikelgrößenverteilung des Akkumulationsmodes in der OT/US gemessen werden. Im April 2010 wurde der neue OPC Einschub erstmals an Bord des Lufthansa Airbus A340-600 (D-AIHE) installiert um die Vulkanasche der Eyjafjallajökull Eruption (April bis Mai 2010) zu messen. Seit Juni 2010 misst der OPC Einschub auf durchschnittlich vier Interkontinentalflügen pro Monat die Partikelgrößenverteilung der OT/US im Größenbereich zwischen 125 und 1300 nm Partikeldurchmesser. Während des Fluges speichert die Datenerfassung alle Rohsignale ab und ermöglicht dadurch eine nutzerspezifische Datenauswertung nach dem Flug (z. B. Anzahl der Größenkanäle oder Zeitauflösung). Im Rahmen dieser Arbeit wurden die Daten mit 32 Größenkanälen und 300 Sekunden analysiert. Da fluggetragene Messungen immer sehr aufwendig sind, beanspruchte die Entwicklung des OPC Einschubs und des Analysealgorithmus, sowie die Charakterisierung und Zertifizierung mehr als zwei Drittel der Gesamtarbeitszeit dieser Arbeit. Daher ist die Analyse der Messdaten auf das erste Jahr der regulären Messungen bis Mai 2011 besch
- Published
- 2015
420. Umweltzone Leipzig: Messtechnische Begleitung der Einführung der Umweltzone in der Stadt Leipzig: Teil 4: Immissionssituation 2010–2014 und Wirkung der Umweltzone
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Löschau, Gunter, Wiedensohler, Alfred, Birmili, Wolfram, Rasch, Fabian, Spindler, Gerald, Müller, Konrad, Hausmann, Andrea, Böttger, Mathias, Bastian, Susanne, Anhalt, Mario, Dietz, Volker, Herrmann, Hartmut, Böhme, Uwe, Wolf, Uwe, Löschau, Gunter, Wiedensohler, Alfred, Birmili, Wolfram, Rasch, Fabian, Spindler, Gerald, Müller, Konrad, Hausmann, Andrea, Böttger, Mathias, Bastian, Susanne, Anhalt, Mario, Dietz, Volker, Herrmann, Hartmut, Böhme, Uwe, and Wolf, Uwe
- Abstract
In Leipzig wurde erstmalig durch ergänzende wissenschaftliche Messungen von Ruß und ultrafeinen Partikeln an Luftmessstationen nachgewiesen, welche Auswirkungen eine Umweltzone auf die Luftqualität hat. Die modernisierte Fahrzeugflotte in der Umweltzone verursachte einen deutlichen Rückgang von lungengängigen Verbrennungspartikeln in straßennaher Außenluft. Verbesserungen für Stickstoffoxide gab es nicht. Durch Minderung der hoch toxischen Bestandteile im Feinstaub wurde ein Beitrag zur Senkung des Gesundheitsrisikos der Bevölkerung geleistet.
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- 2015
421. ACTRIS ACSM intercomparison - Part 1: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with co-located instruments
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Crenn, V., Sciare, J., Croteau, P.L., Verlhac, S., Fröhlich, R., Belis, C.A., Aas, W., Äijälä, M., Alastuey, Andrés, Artíñano, Begoña, Baisnée, D., Bonnaire, N., Bressi, M., Canagaratna, M., Canonaco, F., Carbone, C., Cavalli, F., Coz, Esther, Cubison, M.J., Esser-Gietl, J.K., Green, D.C., Gros, V., Heikkinen, L., Herrmann, Hartmut, Lunder, C., Minguillón, María Cruz, Močnik, G., O'Dowd, Colin D., Ovadnevaite, Jurgita, Petit, J.E., Petralia, E., Poulain, L., Priestman, M., Riffault, V., Ripoll, A., Sarda-Estève, R., Slowik, J.G., Setyan, A., Wiedensohler, Alfred, Baltensperger, U., Prévôt, André S.H., Jayne, J.T., Favez, O., Crenn, V., Sciare, J., Croteau, P.L., Verlhac, S., Fröhlich, R., Belis, C.A., Aas, W., Äijälä, M., Alastuey, Andrés, Artíñano, Begoña, Baisnée, D., Bonnaire, N., Bressi, M., Canagaratna, M., Canonaco, F., Carbone, C., Cavalli, F., Coz, Esther, Cubison, M.J., Esser-Gietl, J.K., Green, D.C., Gros, V., Heikkinen, L., Herrmann, Hartmut, Lunder, C., Minguillón, María Cruz, Močnik, G., O'Dowd, Colin D., Ovadnevaite, Jurgita, Petit, J.E., Petralia, E., Poulain, L., Priestman, M., Riffault, V., Ripoll, A., Sarda-Estève, R., Slowik, J.G., Setyan, A., Wiedensohler, Alfred, Baltensperger, U., Prévôt, André S.H., Jayne, J.T., and Favez, O.
- Abstract
As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for 3 weeks during the late-fall - early-winter period (November-December 2013). The first week was dedicated to the tuning and calibration of each instrument, whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical, and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium, and chloride) in the non-refractory submicron aerosols (NR-PM) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r > 0.9) were observed systematically for each individual Q-ACSM across all chemical families except for chloride for which three Q-ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025, 1999) and were found to be 9, 15, 19, 28, and 36 % for NR-PM, nitrate, organic matter, sulfate, and ammonium, respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of Q-ACSMs, detailed intercomparison results are presented, along with a discussion of some recomme
- Published
- 2015
422. ACTRIS ACSM intercomparison - Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers
- Author
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Fröhlich, R., Crenn, V., Setyan, A., Belis, C.A., Canonaco, F., Favez, O., Riffault, V., Slowik, J.G., Aas, W., Äijälä, M., Alastuey, Andrés, Artíñano, Begoña, Bonnaire, N., Bozzetti, C., Bressi, M., Carbone, C., Coz, Esther, Croteau, P.L., Cubison, M.J., Esser-Gietl, J.K., Green, D.C., Gros, V., Heikkinen, L., Herrmann, Hartmut, Jayne, J.T., Lunder, C.R., Minguillón, María Cruz, MoÄnik, G., O'Dowd, Colin D., Ovadnevaite, Jurgita, Petralia, E., Poulain, L., Priestman, M., Ripoll, A., Sarda-Estève, R., Wiedensohler, Alfred, Baltensperger, U., Sciare, J., Prévôt, André S.H., Fröhlich, R., Crenn, V., Setyan, A., Belis, C.A., Canonaco, F., Favez, O., Riffault, V., Slowik, J.G., Aas, W., Äijälä, M., Alastuey, Andrés, Artíñano, Begoña, Bonnaire, N., Bozzetti, C., Bressi, M., Carbone, C., Coz, Esther, Croteau, P.L., Cubison, M.J., Esser-Gietl, J.K., Green, D.C., Gros, V., Heikkinen, L., Herrmann, Hartmut, Jayne, J.T., Lunder, C.R., Minguillón, María Cruz, MoÄnik, G., O'Dowd, Colin D., Ovadnevaite, Jurgita, Petralia, E., Poulain, L., Priestman, M., Ripoll, A., Sarda-Estève, R., Wiedensohler, Alfred, Baltensperger, U., Sciare, J., and Prévôt, André S.H.
- Abstract
© Author(s) 2015. Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs) performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM) from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM), and one high-resolution ToF aerosol mass spectrometer (AMS) were operated in parallel for about 3 weeks in November and December∼2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF) utilising the multilinear engine 2 (ME-2). Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44), which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA), cooking-related organic aerosol (COA), biomass burning-related organic aerosol (BBOA) and secondary oxygenated organic aerosol (OOA). ME-2 boundary conditions (profile constraints) were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles). A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD) from the mean between 13.7 and 22.7 % of the source's averag
- Published
- 2015
423. Air quality in the German–Czech border region: A focus on harmful fractions of PM and ultrafine particles
- Author
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Schladitz, Alexander, primary, Leníček, Jan, additional, Beneš, Ivan, additional, Kováč, Martin, additional, Skorkovský, Jiří, additional, Soukup, Aleš, additional, Jandlová, Jana, additional, Poulain, Laurent, additional, Plachá, Helena, additional, Löschau, Gunter, additional, and Wiedensohler, Alfred, additional
- Published
- 2015
- Full Text
- View/download PDF
424. Assessing responses of cardiovascular mortality to particulate matter air pollution for pre-, during- and post-2008 Olympics periods
- Author
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Su, Chang, primary, Hampel, Regina, additional, Franck, Ulrich, additional, Wiedensohler, Alfred, additional, Cyrys, Josef, additional, Pan, Xiaochuan, additional, Wichmann, H-Erich, additional, Peters, Annette, additional, Schneider, Alexandra, additional, and Breitner, Susanne, additional
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- 2015
- Full Text
- View/download PDF
425. Heterogeneous N2O5 uptake coefficient and production yield of ClNO2 in polluted northern China: roles of aerosol water content and chemical composition.
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Tham, Yee Jun, Wang, Zhe, Li, Qinyi, Wang, Weihao, Wang, Xinfeng, Lu, Keding, Ma, Nan, Yan, Chao, Kecorius, Simonas, Wiedensohler, Alfred, Zhang, Yuanhang, and Wang, Tao
- Subjects
NITROGEN fixation ,CHLORIDES ,NITRATES ,POLLUTANTS ,HAZE ,HETEROGENEOUS catalysis - Abstract
Heterogeneous uptake of dinitrogen pentoxide (N
2 O5 ) and production of nitryl chloride (ClNO2 ) are important nocturnal atmospheric processes that have significant implications for the production of secondary pollutants. However, the understanding of N2 O5 uptake processes and ClNO2 production remains limited, especially in China. This study presents a field investigation of the N2 O5 heterogeneous uptake coefficient (γ(N2 O5 )) and ClNO2 production yield (ø) in a polluted area of northern China during the summer of 2014. The N2 O5 uptake coefficient and ClNO2 yield were estimated by using the simultaneously measured ClNO2 and total nitrate in 10 selected cases, which have concurrent increases in the ClNO2 and nitrate concentrations and relatively stable environmental conditions. The determined γ (N2 O5 ) and ø values varied greatly, with an average of 0.022 for γ (N2 O5 ) (±0:012, standard deviation) and 0.34 for ø (±0:28, standard deviation). The variations in γ (N2 O5 ) could not be fully explained by the previously derived parameterizations of N2 O5 uptake that consider nitrate, chloride, and the organic coating. Heterogeneous uptake of N2O5 was found to have a strong positive dependence on the relative humidity and aerosol water content. This result suggests that the heterogeneous uptake of N2 O5 in Wangdu is governed mainly by the amount of water in the aerosol, and is strongly water limited, which is different from most of the field observations in the US and Europe. The ClNO2 yield estimated from the parameterization was also overestimated comparing to that derived from the observation. The observation-derived ø showed a decreasing trend with an increasing ratio of acetonitrile to carbon monoxide, an indicator of biomass burning emissions, which suggests a possible suppressive effect on the production yield of ClNO2 in the plumes influenced by biomass burning in this region. The findings of this study illustrate the need to improve our understanding and to parameterize the key factors for γ (N2 O5 ) and ø to accurately assess photochemical and haze pollution. [ABSTRACT FROM AUTHOR]- Published
- 2018
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426. Heterogeneous N2O5 uptake coefficient and production yield of ClNO2 in polluted northern China: Roles of aerosol water content and chemical composition.
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Yee Jun Tham, Zhe Wang, Qinyi Li, Weihao Wang, Xinfeng Wang, Keding Lu, Nan Ma, Chao Yan, Kecorius, Simonas, Wiedensohler, Alfred, Yuanhang Zhang, and Tao Wang
- Abstract
Heterogeneous uptake of dinitrogen pentoxide (N
2 O5 ) and production of nitryl chloride (ClNO2 ) are important nocturnal atmospheric processes that have significant implications for the production of secondary pollutants. However, the understanding of N2 O5 uptake processes and ClNO2 production remains limited, especially in China. This study presents a field investigation of the N2 O5 heterogeneous uptake coefficient (γ(N2 O5 )) and ClNO2 production yield (ϕ) in a polluted area of northern China during the summer of 2014. The N2 O5 uptake coefficient and ClNO2 yield were estimated in 10 selected cases using simultaneously measured concentrations of ClNO2 and particulate nitrate. The determined γ(N2 O5 ) and ϕ values varied greatly, with an average of 0.022 for γ(N2 O5 ) (in range of 0.006–0.034) and 0.34 for ϕ (range, 0.07–1.04). The variations in γ(N2 O5 ) could not be fully explained by the previously derived parameterizations of N2 O5 uptake that consider nitrate, chloride, and the organic coating. Heterogeneous uptake of N2 O5 was found to have a strong positive dependence on the relative humidity and aerosol water content. This result suggests that the heterogeneous uptake of N2 O5 in Wangdu is governed mainly by the amount of water in the aerosol, a phenomenon that differs from other field observations in the United States and Europe. Laboratory-derived parameterization also overestimated the ClNO2 yield. The observation-derived ϕ showed a decreasing trend with an increasing ratio of acetonitrile to carbon monoxide, an indicator of biomass burning emissions, which suggests a possible suppressive effect on the production yield of ClNO2 in the plumes influenced by biomass burning in this region. The findings of this study illustrate the need to improve our understanding and to parameterize the key factors for γ(N2 O5 ) and ϕ to accurately assess the photochemical and haze pollution. [ABSTRACT FROM AUTHOR]- Published
- 2018
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427. Source apportionment of the submicron organic aerosols over the Atlantic Ocean from 53° N to 53° S using HR-ToF-AMS.
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Shan Huang, Zhijun Wu, Poulain, Laurent, van Pinxteren, Manuela, Merkel, Maik, Assmann, Denise, Herrmann, Hartmut, and Wiedensohler, Alfred
- Abstract
The marine aerosol is one of the most important natural aerosol systems and can significantly impact the global climate as well as biological cycle. A series of measurements during four open-ocean cruises in 2011 and 2012 over the Atlantic from 53° N to 53° S were conducted to reveal the physical and chemical properties of the marine boundary layer (MBL) aerosol and its seasonality. Chemical composition of the submicron particles was obtained using the on-line techniques High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) as well as from offline high-volume PM
1 filter samples with a sampling time of 24 hours. Our measurements show that the MBL aerosol particle mass is controlled by sulfate (50 %), followed by organics (21 %), sea salt (12 %), ammonium (9 %), Black Carbon (BC, 5 %) and nitrate (3 %). Only sulfate exhibits pronouncedly seasonal dependency, while no such trend was observed in other species. Source apportionment of the organic fraction was performed using Positive Matrix Factorization (PMF). Five factors were identified, including three marine sources and two non-marine sources. Marine sources are linked to primary production (19 % of total organic aerosol (OA) mass), marine dimethylsulfide (DMS)-oxidation (16 %), and amine-related secondary formation (16 %). The other two OA components are attributed to continental outflow (19 %) and aged ship exhausts – biomass burning emissions (30 %). Our study indicates that, on average, non-marine sources nearly have the equal importance to the Atlantic aerosols comparing with the marine sources, respectively contributing 49 % and 51 % to the total OA mass loadings. The South Atlantic atmosphere is found to be less polluted than the North according to our source analysis. Detailed latitudinal distribution of OA sources showed that DMS oxidation contributes remarkably to the MBL aerosol over the South Atlantic during spring, while continental pollutants largely contaminate the marine atmosphere when near the west and middle Africa (15° N~15° S) as well as Europe. Based on our measurements, SOA produced from DMS oxidation over the Atlantic can be estimated as MSA mass concentration times a scaling factor 1.79 for spring season, which is derived from the strong correlation (R2 > 0.85) between MSA and DMS-oxidation OA component. [ABSTRACT FROM AUTHOR]- Published
- 2018
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428. A parameterization of the heterogeneous hydrolysis of N2O5 for mass-based aerosol models: improvement of particulate nitrate prediction.
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Chen, Ying, Wolke, Ralf, Ran, Liang, Birmili, Wolfram, Spindler, Gerald, Schröder, Wolfram, Su, Hang, Cheng, Yafang, Tegen, Ina, and Wiedensohler, Alfred
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HYDROLYSIS ,ATMOSPHERIC aerosols ,NITRATES ,PARTICULATE matter ,HUMIDITY - Abstract
The heterogeneous hydrolysis of N
2 O5 on the surface of deliquescent aerosol leads to HNO3 formation and acts as a major sink of NOx in the atmosphere during nighttime. The reaction constant of this heterogeneous hydrolysis is determined by temperature (T ), relative humidity (RH), aerosol particle composition, and the surface area concentration (S). However, these parameters were not comprehensively considered in the parameterization of the heterogeneous hydrolysis of N2 O5 in previous mass-based 3-D aerosol modelling studies. In this investigation, we propose a sophisticated parameterization (NewN2 O5 ) of N2 O5 heterogeneous hydrolysis with respect to T, RH, aerosol particle compositions, and S based on laboratory experiments. We evaluated closure between NewN2 O5 and a state-of-the-art parameterization based on a sectional aerosol treatment. The comparison showed a good linear relationship (R D0.91) between these two parameterizations. NewN2 O5 was incorporated into a 3-D fully online coupled model, COSMO- MUSCAT, with the mass-based aerosol treatment. As a case study, we used the data from the HOPE Melpitz campaign (10-25 September 2013) to validate model performance. Here, we investigated the improvement of nitrate prediction over western and central Europe. The modelled particulate nitrate mass concentrations ([NO- 3 ]) were validated by filter measurements over Germany (Neuglobsow, Schmücke, Zingst, and Melpitz). The modelled [NO- 3 ] was significantly overestimated for this period by a factor of 5-19, with the corrected NH3 emissions (reduced by 50 %) and the original parameterization of N2 O5 heterogeneous hydrolysis. The NewN2 O5 significantly reduces the overestimation of [NO- 3 ] by ~35 %. Particularly, the overestimation factor was reduced to approximately 1.4 in our case study (12, 17-18 and 25 September 2013) when [NO- 3 ] was dominated by local chemical formations. In our case, the suppression of organic coating was negligible over western and central Europe, with an influence on [NO- 3 ] of less than 2% on average and 20% at the most significant moment. To obtain a significant impact of the organic coating effect, N2 O5 , SOA, and NH3 need to be present when RH is high and T is low. However, those conditions were rarely fulfilled simultaneously over western and central Europe. Hence, the organic coating effect on the reaction probability of N2 O5 may not be as significant as expected over western and central Europe. [ABSTRACT FROM AUTHOR]- Published
- 2018
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429. Umweltzone Leipzig: Messtechnische Begleitung der Einführung der Umweltzone in der Stadt Leipzig: Teil 1: Ausgangsbeurteilung der Immissionssituation im Jahr 2010vor der Einführung der Umweltzone
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Löschau, Gunter, Wolf, Uwe, Hausmann, Andrea, Wiedensohler, Alfred, Rasch, Fabian, Spindler, Gerald, Müller, Konrad, Birmili, Wolfram, and Herrmann, Hartmut
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ddc:363 ,Luft, Immission, Umweltzone ,air, immission, green zone - Abstract
Zur Einführung der Umweltzone in Leipzig werden begleitende Messungen an 12 Messstationen durchgeführt. Neben den gesetzlich vorgegebenen Schadstoffen werden Sondermessgrößen wie Ruß und die Anzahl ultrafeiner Partikel überwacht. Der erste Teil der Berichterstattung dokumentiert die Messergebnisse im Jahr 2010 vor Einführung der Umweltzone. Er bildet die Ausgangssituation zur Beurteilung der Wirksamkeit der Umweltzone ab. Dargestellt ist auch das Minderungspotenzial einer Umweltzone, das an fünf verkehrsnahen Messstellen in Leipzig und Dresden erstmals ermittelt wurde. Danach können etwa fünf bis zehn PM10-Grenzwertüberschreitungstage vermieden werden.
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- 2012
430. Calibration experiments for filter based absorption photometers during the EUSAAR-2009 photometer workshop
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Müller, Thomas, Henzing, Bas, Sheridan, P.J., Wiedensohler, Alfred, Virkkula, Aki, Mocnik, Grisa, Walker, J., Fialho, Paulo, Eleftheriadis, Kostas, Filep, Agnes, and Leeuw, Gerrit
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Ambient Air Experiments ,Aerossol Atmosférico ,Atmospheric Aerosol ,Aerosol Absorption - Abstract
8th International Aerosol Conference. Helsinki, Finland, August 29-September 3, 2010. Aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Filter based absorption photometers, e.g. the Aethalometer and the Particle Soot Absorption Photometer (PSAP) have been available for several years. Multiple scattering of light in the filter medium and the presence of scattering particles result in a measured attenuation coefficient, which is different from the absorption coefficient of airborne particles. Correction schemes have to be determined experimentally using reference methods (e.g. photoacoustic photometers or extinction minus scattering). Often used correction schemes are described in Bond et al. (1999) and Virkkula et al. (2005) for PSAP and in Weingaartner et al. (2003) for Aethalometer. In the frameworks of EUSAAR a workshop for testing existing and developing new correction schemes has been conducted in 2009 at the Leibniz Institute for Tropospheric Research in Leipzig.
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- 2010
431. Results of the Ambient Air Experiments during the EUSAAR 2009 Absorption Photometer Workshop
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Fialho, Paulo, Müller, Thomas, Henzing, Bas, Dell'Aqua, Alessandro, Eleftheriadis, Kostas, Filep, Agnes, Marinoni, Angela, Mocnik, Grisa, Rondo, Linda, Virkkula, Aki, Wiedensohler, Alfred, and Leeuw, Gerrit
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Ambient Air Experiments ,Aerossol Atmosférico ,Atmospheric Aerosol - Abstract
International Aerosol Conference 2010. Helsinki, Finland, August 29-September 3. Develop methodologies to compensate for apparent absorption caused by scattering dueto the use of filter matrix support.
- Published
- 2010
432. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation
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Spracklen, Dominick V., Carslaw, Kenneth S., Merikanto, Joonas, Mann, Graham W., Pickering, Steven, Ogren, John A., Andrews, Elisabeth, Baltensperger, Urs, Weingartner, Ernest, Boy, Michael, Kulmala, Markku, Laakso, Lauri, Lihavainen, Heikki, Kivekäs, Niku, Mihalopoulos, Nikos, Kouvarakis, G., Jennings, S. Gerard, Birmili, Wolfram, Wiedensohler, Alfred, Weller, Rolf, Laj, Paolo, Sellegri, Karine, Bonn, Boris, and Krejci, Radek
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010504 meteorology & atmospheric sciences ,13. Climate action ,ddc:550 ,010501 environmental sciences ,01 natural sciences ,0105 earth and related environmental sciences - Abstract
We use observations of total particle number concentration at 36 worldwide sites and a global aerosol model to quantify the primary and secondary sources of particle number. We show that emissions of primary particles can reasonably reproduce the spatial pattern of observed condensation nuclei (CN) (R2=0.51) but fail to explain the observed seasonal cycle at many sites (R2=0.1). The modeled CN concentration in the free troposphere is biased low (normalised mean bias, NMB=−88%) unless a secondary source of particles is included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%). Simulated CN concentrations in the continental boundary layer (BL) are also biased low (NMB=−74%) unless the number emission of anthropogenic primary particles is increased or an empirical BL particle formation mechanism based on sulfuric acid is used. We find that the seasonal CN cycle observed at continental BL sites is better simulated by including a BL particle formation mechanism (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). Using sensitivity tests we derive optimum rate coefficients for this nucleation mechanism, which agree with values derived from detailed case studies at individual sites.
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- 2010
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433. Nocturnal aerosol particle formation in the North China Plain
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Kecorius, Simonas, primary, Zhang, Shenglan, additional, Wang, Zhibin, additional, Größ, Johannes, additional, Ma, Nan, additional, Wu, Zhijun, additional, Ran, Liang, additional, Hu, Min, additional, Wang, Pucai, additional, Ulevičius, Vidmantas, additional, and Wiedensohler, Alfred, additional
- Published
- 2015
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434. Mobiler Aerosolstandard - Entwicklung eines mobilen Aerosolstandards
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Birmili, Wolfram, Tuch, Thomas, Wiedensohler, Alfred, and Sonntag, André
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measurement, air quality, aerosol ,ddc:530 ,Messung, Luftqualität, Aerosol - Abstract
Ein mobiler Aerosolstandard für ultrafeine Partikel wurde als neue Möglichkeit zur Qualitätskontrolle für innovative Umweltmessungen in Luftgütemessnetzen entwickelt. Die Bestimmung der Anzahl ultrafeiner Partikel in Ergänzung zur Überwachung von Feinstaub PM10 oder PM2.5 eröffnet neue Möglichkeiten, die Luftqualität zukünftig besser beurteilen zu können. Ultrafeine Partikel sind ein zweckmäßiger Indikator, um z. B. die positive Wirkung einer Umweltzone in Luftreinhalteplänen nachzuweisen.
- Published
- 2010
435. Erratum: An overview of the amazonian aerosol characterization experiment 2008 (AMAZE-08) (Atmospheric Chemistry and Physics (2010) 10 (11415-11438))
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Martin, Scot T., Andreae, Meinrat O., Althausen, Dietrich, Artaxo, Paulo, Baars, Holger, Borrmann, Stephan H., Chen, Qi, Farmer, Delphine K., Guenther, Alex B., Gunthe, Sachin S., Ji?enez, José Luis, Karl, Thomas G., Longo, Karla Maria, Manzi, Antônio Ocimar, Müller, Thomas, Pauliquevis, Theotônio M., Petters, Markus Dirk, Prenni, Anthony J., Pöschl, Ulrich, Rizzo, L. V., Schneider, Johannes, Smith, James N., Swietlicki, Erik, Tóta, Júlio, Wang, Jun, Wiedensohler, Alfred, and Zorn, Soeren R.
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- 2010
436. Characterization and intercomparison of aerosol absorption photometers: result of two intercomparison workshops [Discussion paper]
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Müller, T., Henzing, J. S., Leeuw, Gerardus de, Wiedensohler, Alfred, Alastuey, Andrés, Angelov, H., Bizjak, Milan, Collaud Coen, Martine, Engström, Erik, Gruening, C., Hillamo, R., Hoffer, Andras, Imre, K., Ivanow, P., Jennings, G., Sun, Jielun Y., Kalivitis, Nikos, Karlsson, H., Komppula, M., Laj, Paolo, Li, S.-M., Lunder, Chris, Marinoni, Angela, Martins dos Santos, Sebastiao, Moerman, Marcel, Nowak, Andreas, Ogren, John A., Petzold, Andreas, Pichon, Jean Marc, Rodríguez González, Sergio, Sharma, Sangeeta, Sheridan, P. J., Teinilä, K., Tuch, Thomas, Viana, Mar, Virkkula, A., Weingartner, Ernest, Wilhelm, R., and Wang, Y. Q.
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Photometers ,Aerosol properties ,Aerosoles ,Fotómetros de absorción ,Absorption photometers - Abstract
Absorption photometers for real time application have been available since the 1980s, but the use of filter-based instruments to derive information on aerosol properties (absorption coefficient and black carbon, BC) is still a matter of debate. Several workshops have been conducted to investigate the performance of individual instruments over the intervening years. Two workshops with large sets of aerosol absorption photometers were conducted in 2005 and 2007. The data from these instruments were corrected using existing methods before further analysis. The inter-comparison shows a large variation between the responses to absorbing aerosol particles for different types of instruments. The unit to unit variability between instruments can be up to 30% for Particle Soot Absorption Photometers (PSAPs) and Aethalometers. Multi Angle Absorption Photometers (MAAPs) showed a variability of less than 5%. Reasons for the high variability were identified to be variations in sample flow and spot size. It was observed that different flow rates influence system performance with respect to response to absorption and instrumental noise. Measurements with non absorbing particles showed that the current corrections of a cross sensitivity to particle scattering are not sufficient. Remaining cross sensitivities were found to be a function of the total particle load on the filter. The large variation between the response to absorbing aerosol particles for different types of instruments indicates that current correction functions for absorption photometers are not adequate. The work described in this paper was supported by the EU FP6 Integrated Infrastructures Initiatives (I3) project EUSAAR (European Supersites for Atmospheric Aerosol Research, project FP6-026140), with the EU FP6 Network of Excellence ACCENT (Atmospheric Composition Change: A European Network, project GOCE-CT-2004-505337) and the WMO GAW (Global Atmosphere Watch) program.
- Published
- 2010
437. Influence of water uptake on the aerosol particle light scattering coefficients of the Central European aerosol
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Zieger, Paul, Fierz-Schmidhauser, Rahel, Poulain, Laurent, Mueller, Thomas, Birmili, Wolfram, Spindler, Gerald, Wiedensohler, Alfred, Baltensperger, Urs, Weingartner, Ernest, Zieger, Paul, Fierz-Schmidhauser, Rahel, Poulain, Laurent, Mueller, Thomas, Birmili, Wolfram, Spindler, Gerald, Wiedensohler, Alfred, Baltensperger, Urs, and Weingartner, Ernest
- Abstract
The influence of aerosol water uptake on the aerosol particle light scattering was examined at the regional continental research site Melpitz, Germany. The scattering enhancement factor f(RH), defined as the aerosol particle scattering coefficient at a certain relative humidity (RH) divided by its dry value, was measured using a humidified nephelometer. The chemical composition and other microphysical properties were measured in parallel. f(RH) showed a strong variation, e.g. with values between 1.2 and 3.6 at RH = 85% and lambda = 550 nm. The chemical composition was found to be the main factor determining the magnitude of f(RH), since the magnitude of f(RH) clearly correlated with the inorganic mass fraction measured by an aerosol mass spectrometer (AMS). Hysteresis within the recorded humidograms was observed and explained by long-range transported sea salt. A closure study using Mie theory showed the consistency of the measured parameters., AuthorCount:9
- Published
- 2014
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438. Verknüpfung aerodynamischer und optischer Eigenschaften nichtkugelförmiger atmosphärischer Grobstaubpartikel
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Wiedensohler, Alfred, Covert, David S., Universität Leipzig, Pfeifer, Sascha, Wiedensohler, Alfred, Covert, David S., Universität Leipzig, and Pfeifer, Sascha
- Abstract
Die entsprechend der Quellstärke größte Fraktion des atmosphärischen Aerosols ist der natürliche Grobstaub (Seesalz, Mineralstaub und primär biologische Partikel). Nahezu alle natürlichen Grobstaubpartikel in trockener Phase weisen mehr oder weniger starke Abweichungen von der sphärischen Form auf. Der Einfluss der Asphärizität auf die aerodynamischen und optischen Eigenschaften kann durch sogenannte Formfaktoren unter Verwendung einer Referenzgröße berücksichtigt werden. Für wissenschaftliche Fragestellungen, die sowohl auf aerodynamischen wie auch optischen Aspekten beruhen, bedarf es einer vollständigen Betrachtung des Einflusses der Partikelmorphologie, um ein physikalisch plausibles Ergebnis zu erhalten. Gegenstand dieser Arbeit ist die Analyse der Relationen zwischen aerodynamischen und optischen Eigenschaften. Ziel ist die approximative Darstellung der optischen Formfaktoren durch den aerodynamischen Formfaktor als Maßzahl der Asphärizität. Hierfür wurden sowohl geometrische Formparameter als auch aerodynamische und optische Formfaktoren für ein Ensemble von regelmäßigen und unregelmäßigen Partikeln simuliert. Der Approximation der optischen Formfaktoren durch den aerodynamischen Formfaktor werden theoretische Überlegungen und Ergebnisse numerischer Simulationen vorangestellt. Die optischen Formfaktoren sind dabei primär eine Funktion des Größenparameters (Partikelgröße und Wellenlänge) und des aerodynamischen Formfaktors. In Laborexperimenten wurden beide Abhängigkeiten unter Verwendung von Proben mit Partikeln unterschiedlicher Asphärizität validiert. Die resultierende Approximation ermöglicht eine einfache und konsistente Beschreibung des Einflusses der Partikelmorphologie auf die aerodynamischen und optischen Eigenschaften. Dies ist eine unabdingbare Voraussetzung für eine genauere Analyse von Partikeleigenschaften, die aus aerodynamisch und optisch basierten In-situ-Messungen abgeleitet werden.
- Published
- 2014
439. Experimental determination of the mass deposition flux of mineral dust at the Cape Verde Islands
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Wiedensohler, Alfred, Klemm, Otto, Universität Leipzig, Niedermeier, Nicole, Wiedensohler, Alfred, Klemm, Otto, Universität Leipzig, and Niedermeier, Nicole
- Abstract
Der Eintrag von Mineralstaub in den Ozean geschieht entweder durch trockene oder durch nasse Deposition. Dies ist ein wichtiger Prozess um ozeanische Organismen wie Phytoplankton mit Nährstoffen (z.B. Nitrat, Phosphat oder Eisen) zu versorgen. Viele Modelle befassen sich mit der Simulation von Depositionsflüssen von Mineralstaub in den Ozean. Messungen von Massendepositionsflüssen von Mineralstaub sind hingegen selten. Daher ist es von großer Notwendigkeit, diese Messungen durchzuführen um die vielen Modelle zu validieren und den Mineralstaubzyklus besser zu verstehen. Innerhalb des SOPRAN Projektes (Surface Ocean PRocesses in the ANthropocene) wird der Materialtransport zwischen der Atmosphäre und dem Ozean untersucht. Die Messungen dafür wurden auf den Kapverdischen Inseln durchgeführt, über welchen der Saharastaub durch die Passatwindzirkulation vorwiegend transportiert wird. Im Rahmen dieser Arbeit werden in-situ Messungen von trockener Deposition von Mineralstaub in den Ozean präsentiert. Verschiedene Methoden wurden auf ihre Anwendbarkeit getestet und deren Ergebnisse miteinander verglichen. Alle Messergebnisse liegen im Bereich der Messunsicherheiten, wodurch ein Satz qualitätsgesicherter Daten aufgebaut werden konnte. Diese Daten wurden mit den Ergebnissen eines regionalen Chemie-Transport Modells verglichen. Modellierte Massendepositionsflüsse von Mineralstaub waren manchmal doppelt so hoch wie gemessene. Die größte Unsicherheit der Modelle liegt in der Emission des Mineralstaubs, die im Transport und der Deposition fortgesetzt wird. Weitere Unterschiede entstehen durch den Vergleich von Punktmessungen mit einer Gitterzelle, wenn der Staub nicht gleichmäßig über die Gitterzelle verteilt ist. Zusammenfassend wurden Massendepositionsmessungen von Mineralstaub erfolgreich mit verschiedenen Methoden durchgeführt. Mit den Erfahrungen aus dieser Studie ist es nun möglich, Langzeitmessungen von Mineralstaubdeposition in den Ozean erstellen. Diese Daten können von, The input of mineral dust to the oceans, via dry or wet deposition, is an important process, because the entrainment of nutrients (e.g., Nitrate, Phosphor and Iron) is essential for oceanic life such as phytoplankton. A lot of effort has been done to model the dust deposition fluxes to the ocean. However, field measurements concerning the deposition flux are sparse. Therefore, those measurements are needed in order to verify the huge amount of model outputs and to better understand the mineral dust cycle. Within the project SOPRAN (Surface Ocean PRocesses in the ANthropocene), the influence of material exchange between the atmosphere and the ocean is investigated. Measurements were carried out at the Cape Verde Islands in the direct outflow of the Saharan Desert. This study presents the first in-situ measurements of the dry mass deposition flux of mineral dust to the ocean. The applicability of different methods was tested and the results were compared to each other. The results of the measured data were comparable and a set of quality assured data could be built up. Those results were compared to the output of a regional chemistry- transport model. The modeled mass deposition flux was sometimes double as high as the measured one. The main uncertainty of the models is the emission of mineral dust at the source region, proceeding in the transport and emission of mineral dust. Furthermore, comparing single point measurements with outputs of a grid cell leads to differences in deposition fluxes by an inhomogeneous distribution of the mineral dust layer. Summarizing, the measurements of the mass deposition flux of mineral dust could be performed successfully with several methods. With the expertise of this study, long-term observations of the mineral dust deposition to the ocean can now be established. These data can be used by atmosphere modelers to validate their models. Ocean modelers and partners of the SOPRAN project will use these data to investigate e.g., the bio
- Published
- 2014
440. Meteorologische Einflüsse auf die Konzentrationen feiner und grober atmosphärischer Aerosolpartikel in Deutschland
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Wiedensohler, Alfred, Builtjes, Peter J.H., Fakultät für Physik und Geowissenschaften, Engler, Christa, Wiedensohler, Alfred, Builtjes, Peter J.H., Fakultät für Physik und Geowissenschaften, and Engler, Christa
- Abstract
Atmosphärische Aerosolpartikel können durch ein breites Spektrum an natürlichen oder anthropogenen Emissionen mit unterschiedlich hohen Konzentrationen in die Atmosphäre freigesetzt werden. Sie beeinflussen den Strahlungshaushalt und damit auch das Klima der Erde und können außerdem durch ihre Präsenz in der Atmosphäre Wechselwirkungen mit Mensch und Natur, also dem gesamten Ökosystem haben. Seit dem Jahr 2010 gelten in der EU Grenzwerte für die PM10 Tagesmittelkonzentration, die jedoch bereits wenige Monate nach Beginn der Gültigkeit an vielen Messstationen überschritten wurden. Das Ziel der vorliegenden Arbeit war eine objektive Bewertung der Herkunft und des Zustandes der an einem Messort ankommenden Luftmasse und der damit verbundenen Schadstoffniveaus. Im ersten Teil der Arbeit wurden PM10 Messdaten aus fünf Jahren in und um Leipzig sowie analog in fünf verschiedenen Regionen deutschlandweit in Bezug auf PM10 Grenzwertüberschreitungen untersucht. Es wurden Rückwärtstrajektorien für eine Clusteranalyse verwendet, mit der spezifische Wetterlagen unterschieden wurden und diesen dann die einzelnen Messtage mit den zugehörigen Schadstoffkonzentrationen zugeordnet wurden. Hierbei wurde deutlich, dass durch entsprechende meteorologische Bedingungen sowohl lokal als auch regional emittierte Schadstoffe in Bodennähe akkumulieren oder aber auch räumlich verteilt werden können. Außerdem wurde in dieser Arbeit eine Modellvalidierung vorgestellt. Es wurde das Modellsystem COSMO-MUSCAT/ext-M7 verwendet, dessen Ergebnisse mit Beobachtungsdaten verglichen wurden. Als erstes wurde die Beschreibung der meteorologischen Bedingungen, dann die räumliche Verteilung von PM10, die chemische Partikelzusammensetzung sowie physikalische Aerosolparameter wie Partikelanzahl, -volumen und -durchmesser verglichen. Die Ergebnisse deuten darauf hin, dass nach wie vor Probleme bei der Beschreibung der mikrophysikalischen Aerosoleigenschaften bestehen. Die Größenordnungen der verglichenen Parame
- Published
- 2014
441. Microphysical properties of aerosol particles in the trade wind regime and their influence on the number concentration of activated particles in trade wind cumulus clouds
- Author
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Wiedensohler, Alfred, Schwarzenböck, Alfons, Universität Leipzig, Ditas, Florian, Wiedensohler, Alfred, Schwarzenböck, Alfons, Universität Leipzig, and Ditas, Florian
- Abstract
Im Rahmen dieser Dissertation wurden die mikrophysikalischen Eigenschaften von Aerosolpartikeln im Passatklima und deren Einfluss auf Passatwolken untersucht. Die Arbeit basiert auf Messungen mit der hubschrauber-getragenen Messplattform ACTOS. Es wurden zwei Intensivmesskampagnen im November 2010 und April 2011 durchgeführt, welche 31 Forschungsflüge in der Nähe der östlichsten Karibik-Insel Barbados umfassen. Die gemessenen Partikel-Anzahl-Größenverteilungen weisen meist eine bimodale Verteilung auf, welche typisch für marines Aerosol ist. Im Vergleich zu kontinentalen Verhältnissen ist die Totalanzahlkonzentration der Aerosolpartikel von 100-1000 cm-3 gering. Eine statistische Analyse einzelner Wolken lässt auf typische Anzahlkonzentrationen von aktivierten Partikeln bis zu 400 cm-3 und minimale Aktivierungsdurchmesser in der Größenordnung von 40 nm bis 180 nm mit entsprechenden maximalen kritischen Übersättigungen zwischen 0.1 und 0.9% schließen. Zusätzlich wurden wesentliche Einflussfaktoren auf die Anzahlkonzentration aktivierter Partikel identifiziert: 1) Vertikalwind an der Wolkenunterkante und 2) Anzahlkonzentration der verfügbaren Aerosolpartikel, die als Wolkenkondensationskeime dienen können. Mit Hilfe von Beobachtungsdaten und einer umfassenden Sensitivitätsstudie unter Verwendung eines Luftpaketmodells mit spektraler Wolkenmikrophysik wurde die Sensitivität der Wolkentropfenkonzentration gegenüber Änderungen in den physikalischen Eigenschaften und der Hygroskopizität von Aerosolpartikeln untersucht. Die beobachteten Ergebnisse in Form von sogenannten \"aerosol-cloud interaction metrics\" (ACI, Maß für den Einfluss von Änderungen einer bestimmten Aerosoleigenschaft auf eine bestimmte Wolkeneigenschaft) zeigen eine sehr hohe Sensitivität der Tropfenanzahlkonzentration gegenüber Änderungen in der Partikelanzahlkonzentration (in der Nähe des physikalisch sinnvollen Maximums von eins). Diese abgeleiteten ACI-Metriken eignen sich als Basis für Abschätzungen, Within the scope of this dissertation, microphysical properties of aerosol particles in the trade wind regime and their influence on microphysical properties of trade wind cumulus clouds have been investigated. The study is based on measurements performed with the helicopter-borne measurement platform ACTOS. Two intensive measurement periods were carried out in November 2010 and April 2011, including 31 research flights close to the easternmost Caribbean island - Barbados. Aerosol particle number size distributions show a bimodal structure, which is typical for marine aerosol particles. The total particle concentrations of approximately 100-1000 cm-3 are compared to continental conditions relatively low. A statistical analysis of individual clouds reveals typical number concentrations of activated particles up to 400 cm-3 and minimum activation diameters between 40 and 180 nm with corresponding critical supersaturations between 0.1 and 1%. Additionally, major factors affecting the number concentration of activated particles are identifed: 1) vertical wind velocity at cloud base and, 2) number concentration of available aerosol particles as potential cloud condensation nuclei. With the help of observational data and a comprehensive sensitivity study using a spectral cloud microphysical parcel model, the sensitivity of the cloud droplet number concentration towards changes in the microphysical aerosol particle properties and their hygroscopicity has been investigated. Observational results in terms of so-called aerosol-cloud interactions metrics (describes a measure of the influence of changes in one specific aerosol property on one specific cloud property) show a very high sensitivity (close to the physical meaningful maximum of unity) of the number concentration of activated particles towards changes in the particle number concentration. These aerosol-cloud interaction metrics can be used as basis for observationally-based radiative forcing estimates. Additional mod
- Published
- 2014
442. Critical assessment of meteorological conditions and airflow connectivity during HCCT-2010
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Tilgner, Andreas, Schöne, Luisa, Bräuer, Peter, Pinxteren, Dominik van, Hoffmann, E., Spindler, Gerald, Mertes, Stephan, Birmili, Wolfram, Otto, Robert, Merkel, Maik, Weinhold, Kay, Wiedensohler, Alfred, Deneke, Hartwig, Haunold, Werner, Engel, Andreas, Wéber, A., Hartmut, Herrmann, Tilgner, Andreas, Schöne, Luisa, Bräuer, Peter, Pinxteren, Dominik van, Hoffmann, E., Spindler, Gerald, Mertes, Stephan, Birmili, Wolfram, Otto, Robert, Merkel, Maik, Weinhold, Kay, Wiedensohler, Alfred, Deneke, Hartwig, Haunold, Werner, Engel, Andreas, Wéber, A., and Hartmut, Herrmann
- Abstract
This study presents a comprehensive and critical assessment of the meteorological conditions and atmospheric flow during the Lagrangian-type "Hill Cap Cloud Thuringia 2010" experiment (HCCT-2010). HCCT-2010 was performed in September and October 2010 at Mt. Schmücke in the Thuringian forest, Germany, applying three measurements sites (upwind, in-cloud, downwind) to study physical and chemical aerosol-cloud-interactions. A Lagrangian-type hill cap cloud experiment requires suitable cloud and particularly connected airflow conditions, i.e. representative air masses at the different measurement sites. Therefore, the present study aimed at the identification of time periods during the 6-weeks duration of the campaign, where such conditions were fulfilled and which can be used in further data examinations. The following topics were studied in detail: (i) the general synoptic weather situations including the mesoscale flow conditions by means of a classification of advected air masses and calculation of non-dimensional flow parameters (e.g. Froude number), (ii) local meteorological conditions, including synoptic front passages, the presence of orographic or frontal cloudiness, cloud base heights and vertical stratification, and (iii) local flow conditions by means of statistical analyses using the quasi-inert trace gas ozone and selected size bins of particle number size distributions as well as SF6 tracer experiments in the campaign area. A comprehensive analyses using statistical measures such as the COD (Coefficient Of Divergence) and cross-correlation have been carried out for the first time in the context of a Lagrangian-type hill cap cloud experiment. Suitable criteria for the aimed statistical analyses were thus developed and applied in the present study to characterise the local flow connectivity in detail. The comprehensive examination resulted in a total of 14 so-called "Full Cloud Events" (FCE), which are shown to conform to the Lagrange-type experimental philo
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- 2014
443. UFIPOLNET: Concentration of Particle Number Distributions at 4 Stations in Europe
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Gerwig, Holger, Löschau, Gunter, Hillemann, Lars, Wehner, Birgit, Wiedensohler, Alfred, Zschoppe, Andreas, Peters, Christian, Rudolph, Andreas, Johansson, Christer, Jodef Cyrys, Pitz, Mike, Rückerl, Regina, Jiri Novak, Horn, Hans Georg, Caldow, Rob, and Sem, Gilmore J.
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- 2007
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444. Helicopter-borne observations of the continental background aerosol in combination with remote sensing and ground-based measurements.
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Düsing, Sebastian, Wehner, Birgit, Seifert, Patric, Ansmann, Albert, Baars, Holger, Ditas, Florian, Henning, Silvia, Nan Ma, Poulain, Laurent, Siebert, Holger, Wiedensohler, Alfred, and Macke, Andreas
- Abstract
This study presents vertical profiles up to a height of 2300 m a.s.l. of aerosol microphysical and optical properties and cloud condensation nuclei (CCN). Corresponding data have been measured during a field campaign as part of the High-Definition Clouds and Precipitation for Advancing Climate Prediction (HD(CP)2) Observational Prototype Experiments (HOPE), which took place at Melpitz, Germany from September 9 to 29, 2013. The helicopter-borne payload ACTOS (Airborne Cloud and Turbulence Observation System) was used to determine the aerosol particle number size distribution (PNSD), the number concentrations of aerosol particles (PNC) and cloud condensation nuclei (CCN) (CCN-NC), the ambient relative humidity (RH), and temperature (T). Simultaneous measurements on ground provided a holistic view on aerosol microphysical properties such as the PNSD, the chemical composition and the CCN-NC. Additional measurements of a 3 + 2 wavelength polarization lidar system (Polly
XT ) provided profiles of the aerosol particle light backscatter coefficient (σbsc) for three wavelengths (355, 532 and 1064 nm). From profiles of σbsc profiles of the aerosol particle light extinction coefficient (σext ) were determined using the extinction-to-backscatter ratio. Furthermore, CCN-NC profiles were estimated on basis of the lidar-measurements. Ambient state optical properties of aerosol particles were derived on the basis of airborne in situ measurements of ACTOS (PNSD) and in situ measurements on ground (chemical aerosol characterization) using Mie-theory. On the basis of ground-based and airborne measurements, this work investigates the representativeness of ground-based aerosol microphysical properties for the boundary layer for two case-studies. The PNSD measurements on ground showed a good agreement with the measurements provided with ACTOS for lower altitudes. The ground-based measurements of PNC and CCN-NC are representative for the PBL when the PBL is well mixed. Locally isolated new particle formation events on ground or at the top of the PBL led to vertical variability in the here presented cases and ground-based measurements are not representative for the PBL. Furthermore, the lidar-based estimates of CCN-NC profiles were compared with the airborne in situ measurements of ACTOS. This comparison showed good agreements within the uncertainty range. Finally, this work provides a closure study between the optical aerosol particle properties in ambient state based on the airborne ACTOS measurements and derived with the lidar measurements. The investigation of the optical properties shows for 14 measurement-points that the airborne-based particle light backscatter coefficient is for 1064 nm 50 % smaller than the measurements of the lidar system, 27.6 % smaller for 532 nm and 29.9 % smaller for 355 nm. These results are quite promising, since in-situ measurement based Mie-calculations of the particle light backscattering are scarce and the modelling is quite challenging. In contradiction for the particle light extinction coefficient retrieved from the airborne in situ measurements were found a good agreement. The airborne-based particle light extinction coefficient was just 7.9 % larger for 532 nm and 3.5 % smaller for 355 nm, for an assumed lidar ratio (LR) of 55 sr. The particle light extinction coefficient for 1064 nm was derived with a LR of 30 sr. For this wavelength, the airborne-based particle light extinction coefficient is 5.2 % smaller than the lidar-measurements. Also, the correlation for the particle light extinction coefficient in combination with Mie-based LR's are in agreement for typical LR's of European background aerosol. [ABSTRACT FROM AUTHOR]- Published
- 2017
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445. Vertical distribution of aerosol optical properties in the Po Valley during the 2012 summer campaigns.
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Bucci, Silvia, Cristofanelli, Paolo, Decesari, Stefano, Marinoni, Angela, Sandrini, Silvia, Größ, Johannes, Wiedensohler, Alfred, Di Marco, Chiara F., Nemitz, Eiko, Cairo, Francesco, Di Liberto, Luca, and Fierli, Federico
- Abstract
Studying the vertical distribution of aerosol particles physical and chemical properties in the troposphere is essential to understand the relative importance of local emissions processes vs. long-range transport on column-integrated aerosol properties (e.g. the aerosol optical depth (AOD), affecting regional climate) as well as on the aerosol burden and its impacts on air quality at the ground. The main objective of this paper is to investigate the transport of desert dust in the middle troposphere and its intrusion into the planetary boundary layer (PBL) over the Po Valley (Italy), a region considered one of the major European pollution hot-spots for the frequency of particulate matter (PM) limit values exceedances. Events of mineral aerosol uplift from local (soil) sources and phenomena of hygroscopic growth at the ground are also investigated, possibly affecting the PM concentration in the region as well. During the PEGASOS 2012 field campaign, an integrated observing-modeling system was set up based on near-surface measurements (particle concentration and chemistry), vertical profiling (backscatter coefficient profiles from LiDAR and radiosoundings) and Lagrangian air masses transport simulations by FLEXPART model. Measurements were taken at the San Pietro Capofiume supersite (44°39' N, 11°37'0 E, 11 m a.s.l.), located in a rural area relatively close to some major urban and industrial emissive areas in the Po Valley. Mt. Cimone (44°12' N, 10°42' E, 2165 m a.s.l.) WMO/GAW station observations are also included in the study to characterize regional-scale variability. Results show that, in the Po Valley, aerosol is detected mainly below 2000 m a.s.l. with a prevalent occurrence of non-depolarizing particles (>50 % throughout the campaign) and a vertical distribution modulated by the PBL daily evolution. Two intense events of mineral dust transport from Northern Africa (19-21 June and 29 June to 2 July) are observed, with layers advected mainly above 2000 m height, but lately sinking and mixing in the PBL. As a consequence, a non-negligible occurrence of mineral dust is observed close to the ground (~7 % of occurrence during a 1-month campaign). The observations unambiguously show Saharan dust layers intruding the Po Valley summertime mixing layer and directly affecting the aerosol concentrations near the surface. Finally, LiDAR observations indicate also strong variability in aerosol on shorter timescales (hourly) highlighting: a) events of hygroscopic growth of anthropogenic aerosol, visible in shallow layers of low depolarization near the ground. Such events are identified during early morning hours at high relative humidity (RH) conditions (RH > 80 %). The process is observed concurrently with high PM1 nitrate concentration (up to 15 μg cm
-3 ), hence mainly explicable by deliquescence of fine anthropogenic particles, and during mineral dust intrusion episodes, when water condensation on dust particles could instead represent the dominant contribution; b) frequent events (mean diurnal occurrence of ~22 % during the whole campaign) of rapid uplift of mineral depolarizing particles in afternoon-evening hours up to 2000 m a.s.l. height. The origin of such particles cannot be directly related to long-range transport events, being instead likely linked to processes of soil particles resuspension from agricultural lands. [ABSTRACT FROM AUTHOR]- Published
- 2017
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446. Contributions of Transported Prudhoe Bay Oilfield Emissions to the Aerosol Population in Utqiaġvik, Alaska.
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Gunsch, Matthew J., Kirpes, Rachel M., Kolesar, Katheryn R., Barrett, Tate E., China, Swarup, Sheesley, Rebecca J., Laskin, Alexander, Wiedensohler, Alfred, Tuch, Thomas, and Pratt, Kerri A.
- Abstract
Loss of sea ice is opening the Arctic to increasing development involving oil and gas extraction and shipping. Given the significant impacts of absorbing aerosol and secondary aerosol precursors emitted within the rapidly warming Arctic region, there is a need to characterize local anthropogenic aerosol sources and compare to natural conditions. From August-September 2015 in Utqiaġvik, AK, the chemical composition of individual atmospheric particles was measured by computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (0.13-4 μm projected area diameter) and real-time single particle mass spectrometry (0.2-1.5μm aerodynamic diameter). During Arctic Ocean influenced periods (70% of the study), our results show that fresh sea spray aerosol contributed ~20%, by number, of particles between 0.13-0.4μm, 40-70% between 0.4-1μm, and 80-100% of 1-4μm particles. In contrast, for periods influenced by emissions from Prudhoe Bay (10% of the study), the third largest oilfield in North America, there was a strong influence from submicron (0.13-1μm) combustion derived particles (20-50% OC, by number, 5-10% soot by number). While sea spray aerosol still comprised a large fraction of particles (90% by number from 1-4μm) detected under Prudhoe Bay influence, these particles were internally mixed with sulfate and nitrate indicative of aging processes during transport. In addition, the overall mode of the particle size number distribution shifted from 76nm during Arctic Ocean influence to 27nm during Prudhoe Bay influence with particle concentrations increasing from 130cm
-3 to 920cm-3 due to transported particle emissions from the oil fields. The increased contributions of carbonaceous combustion products and partially aged SSA should be taken into consideration for future Arctic atmospheric composition and climate simulations. [ABSTRACT FROM AUTHOR]- Published
- 2017
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447. Mixing State of Refractory Black Carbon of the North China Plain Regional Aerosol Combining a Single Particle Soot Photometer and a Volatility Tandem Differential Mobility Analyzer.
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Yuxuan Zhang, Hang Su, Kecorius, Simonas, Zhibin Wang, Min Hu, Tong Zhu, Kebin He, Wiedensohler, Alfred, Qiang Zhang, and Yafang Cheng
- Abstract
Black carbon (BC) aerosol particles play an important role in regulating earth's climate and their climate effects depend on their mixing state. During the CAREBeijing 2013 campaign, we measured the size-resolved mixing state of refractory BC particles in North China Plain and performed intercomparison between a single particle soot photometer (SP2) and a volatility tandem differential mobility analyzer (VTDMA). The intercomparison shows a good agreement between the optical particle diameter determined by SP2 and the mobility particle diameter determined by VTDMA for non-BC as well as for internally mixed refractory BC particles. The VTDMA shows a higher concentration of refractory particles than that of the SP2, which suggests the existence of a large fraction of low volatile non-BC aerosols. Following parameters were constrained by closure studies to improve the inversion of the mixing state of ambient BC (i.e., coating thickness (CT) and shell/core ratio (D
p / Dc )) by SP2: a) refractive indices (RI) of 1.42 and 1.67-0.56i for non-BC and rBC core components, respectively, b) refractory BC (rBC) core density of 1.2 g cm-3 for internally-mixed BC particles, and c) an effective density range of 0.25-0.45 g cm-3 for externally-mixed BC particles. Moreover, the upper limit of the measurable particle size of SP2 was extended by the leading-edge-only (LEO) fit from ~ 400 nm to ~ 550 nm as confirmed by the VTDMA measurement. Based on the improved inversion from SP2 measurement, we found that non-BC containing particles, internally-mixed BC and externally-mixed BC contribute 85-90 %, 5-7 % and 5-10 % of the total aerosol number in the size range of 200 nm to 350 nm. The number fraction of internally-mixed BC in total BC-containing aerosols (Fin) shows pronounced diurnal cycles with a peak around noon time and an apparent turnover rate up to 6-9 % h-1 . Such diurnal cycles are similar to the finding of Cheng et al. (2012) suggesting the competing effect of emissions and aging processes. In this study, the observed internally-mixed BC particles in the polluted regional NCP (North China Plain) background site (Xianghe) suggest a rapid aging process of BC on the regional scale. During the intensive field study period, ~ 80 % of internally-mixed BC particles at 200-300 nm showed a Dp / Dc ratio of more than 2, accompanying with an average value of 2.3-2.8. Meanwhile, the CT of internally-mixed BC particles (200-350 nm) with rBC core size of 80-200 nm was in the range of 50-150 nm. Compared with previous measurements in developed countries, the observed BC particles on regional scale (i.e., internally-mixed BC particles) were more-aged, indicating stronger optical and climate effect of BC on the regional scale in northern China. [ABSTRACT FROM AUTHOR]- Published
- 2017
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448. A Parameterization of Heterogeneous Hydrolysis of N2O5 for 3-D Atmospheric Modelling: Improvement of Particulate Nitrate Prediction.
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Ying Chen, Wolke, Ralf, Liang Ran, Birmili, Wolfram, Spindler, Gerald, Schröder, Wolfram, Hang Su, Yafang Cheng, Tegen, Ina, and Wiedensohler, Alfred
- Abstract
Heterogeneous hydrolysis of N
2 O5 on the surface of deliquescent aerosol particles leads to HNO3 formation and acts as a major sink of NOx in the atmosphere during nighttime. The reaction constant of this heterogeneous hydrolysis is determined by temperature (T), relative humidity (RH), aerosol particle composition as well as the surface area concentration (S). However, its parameterization in previous 3-D modelling studies did not comprehensively consider these parameters. In this investigation, we propose a sophisticated parameterization of the heterogeneous hydrolysis of N2 O5 with respect to T, RH, aerosol particle compositions and S, based on laboratory experiments. This new parameterization was incorporated into a 3-D fully online coupled model: COSMO-MUSCAT. As case study, we used the data from the HOPE-Melpitz campaign (10-25 September 2013). Here, we investigated the improvement of nitrate prediction over the western and central Europe. The modelled particulate nitrate mass concentrations ([NO3 - ]) were validated by filter measurements over Germany (Neuglobsow, Schmücke, Zingst, and Melpitz). The modelled [NO3 - ] were significantly overestimated for this period by a factor of 5-19, with the corrected NH3 emissions (reduced by 50 %) and the original parameterization of N2 O5 heterogeneous hydrolysis. The proposed new parameterization significantly reduces the overestimation of [NO3 - ] by ~ 35 %. Particularly, the overestimation factor was reduced to approximately 1.4 within our case study period (September 12, 17-18 and 25, 2013), when [NO3 - ] was dominated by local chemical formations. Furthermore, the organic coating effect on a suppression of the N2 O5 reaction probability may have been also significantly overestimated in previous modelling studies, due to a strong overestimation of the N2 O5 reaction probability on coatings. Based on the original parameterization, previous studies reported a decrease of modelled [NO3 - ] up to 90 %, where both secondary organic aerosol (SOA) and N2 O5 were built-up over western and central Europe. For this case study, the suppression of organic coating was negligible over western and central Europe, with influence on [NO3 - ] less than 2 % on average and 20 % at the most significant moment. As for a significant impact of the organic coating effect, N2 O5 , SOA and NH3 need to be present when RH is high and T is low. However, those conditions were rarely fulfilled simultaneously over western and central Europe. Hence, the organic coating effect on reaction probability of N2 O5 over Europe may not be as important as expected in previous studies. [ABSTRACT FROM AUTHOR]- Published
- 2017
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449. Latitudinal and Seasonal Distribution of Particulate MSA over the Atlantic using a Validated Quantification Method with HR-ToF-AMS.
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Huang, Shan, Poulain, Laurent, van Pinxteren, Dominik, van Pinxteren, Manuela, Wu, Zhijun, Herrmann, Hartmut, and Wiedensohler, Alfred
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- 2017
- Full Text
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450. Episodes of high pollution in Beijing, China
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Wehner, Birgit, Wu, Zhijun, Hu, Min, Massling, Andreas, and Wiedensohler, Alfred
- Published
- 2005
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