Auflistung nach Autor:in "Gruening, Carsten"

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Characterization and intercomparison of aerosol absorption photometers. result of two intercomparison workshops
(Copernicus, 2011) Müller, Thomas; Henzing, Bas; de Leeuw, Gerrit; Wiedensohler, Alfred; Alastuey, Andrés; Angelov, H.; Bizjak, Milan; Collaud Coen, Martine; Engström, J. E.; Gruening, Carsten; Hillamo, Risto; Hoffer, András; Imre, Kornélia; Ivanow, Petko; Jennings, Stephen G.; Sun, Junying; Kalivitis, Nikos; Karlsson, Hanna; Komppula, Mikka; 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; Rodriquez, Sergio; Sharma, Sangeeta; Sheridan, Patrick J.; Teinilä, Kimmo; Tuch, Thomas; Viana, Mar; Virkkula, Aki; Weingartner, Ernest; Wilhelm, R.; Wang, Yaqiang
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.
01A - Beitrag in wissenschaftlicher Zeitschrift
Intercomparison study of six HTDMAs. results and recommendations
(Copernicus, 24.07.2009) Duplissy, Jonathan; Gysel, Martin; Sjogren, S.; Meyer, Nickolas; Good, Nicholas; Kammermann, Lukas; Michaud, Vincent; Weigel, Ralf; Martins dos Santos, Sebastiao; Gruening, Carsten; Villani, P.; Laj, Paolo; Sellegri, Karine; Metzger, Axel; McFiggans, Gordon B.; Wehrle, Günther; Richter, René; Dommen, Josef; Ristovski, Zoran; Baltensperger, Urs; Weingartner, Ernest
We report on an intercomparison of six different hygroscopicity tandem differential mobility analysers HTDMAs). These HTDMAs are used worldwide in laboratory experiments and field campaigns to measure the water uptake of aerosol particles and have never been intercompared. After an investigation of the different design of the instruments with their advantages and inconveniencies, the methods for calibration, validation and data analysis are presented. Measurements of nebulised ammonium sulphate as well as of secondary organic aerosol generated from a smog chamber were performed. Agreement and discrepancies between the instruments and to the theory are discussed, and final recommendations for a standard instrument are given, as a benchmark for laboratory or field experiments to ensure a high quality of HTDMA data.
01A - Beitrag in wissenschaftlicher Zeitschrift
Mobility particle size spectrometers. harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions
(Copernicus, 29.03.2012) Wiedensohler, Alfred; Birmili, Wolfram; Nowak, Marta; Sonntag, André; Weinhold, Kay; Merkel, Maik; Wehner, Birgit; Tuch, Thomas; Pfeifer, Sascha; Fiebig, Markus; Fjäraa, Ann Mari; Asmi, Eija; Sellegri, Karine; Depuy, R.; Venzac, Hervé; Villani, Paolo; Laj, Paolo; Aalto, Pasi Pekka; Ogren, John A.; Swietlicki, Erik; Williams, Paul I.; Roldin, Pontus; Quincey, Paul; Hüglin, Christoph; Fierz-Schmidhauser, Rahel; Gysel, Martin; Weingartner, Ernest; Riccobono, Francesco; Santos, S.; Gruening, Carsten; Faloon, K.; Beddows, D.; Harrison, Roy; Monahan, C.; Jennings, Stephen G.; O'Dowd, Colin D.; Marinoni, Angela; Horn, H.-G.; Keck, L.; Jiang, Jingkun; Scheckman, Jakob; McMurry, Peter H.; Deng, Zhaoze; Zhao, Chunsheng; Moerman, Marcel; Henzing, Bas; de Leeuw, Gerrit; Löschau, G.; Bastian, S.
Abstract. Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5%. Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.
01A - Beitrag in wissenschaftlicher Zeitschrift
Primary versus secondary contributions to particle number concentrations in the European boundary layer
(Copernicus, 05.12.2011) Reddington, Carly L.; Carslaw, Ken S.; Spracklen, Dominick V.; Frontoso, Maria Grazia; Collins, Lisa M.; Merikanto, Joonas; Minikin, Andreas; Hamburger, Thomas; Coe, Hugh; Kulmala, Markku; Aalto, Pasi Pekka; Flentje, Harald; Plass-Dülmer, Christian; Birmili, Wolfram; Wiedensohler, Alfred; Wehner, Birgit; Tuch, Thomas; Sonntag, Alfred; O'Dowd, Collin D.; Jennings, Stephen G.; Dupuy, Regis; Baltensperger, Urs; Weingartner, Ernest; Hansson, Hans-Christen; Tunved, Peter; Laj, Paolo; Sellegri, Karine; Boulon, Julien; Putaud, Jean-Philippe; Gruening, Carsten; Swietlicki, Erik; Roldin, Pontus; Henzing, J.S.; Moerman, Marcel; Mihalopoulos, Nikolaos; Kouvarakis, Giorgos; Ždímal, Vladimir; Zíková, Nadezda; Marinoni, Angela; Bonasoni, Paolo; Duchi, Rocco
It is important to understand the relative contribution of primary and secondary particles to regional and global aerosol so that models can attribute aerosol radiative forcing to different sources. In large-scale models, there is considerable uncertainty associated with treatments of particle formation (nucleation) in the boundary layer (BL) and in the size distribution of emitted primary particles, leading to uncertainties in predicted cloud condensation nuclei (CCN) concentrations. Here we quantify how primary particle emissions and secondary particle formation influence size-resolved particle number concentrations in the BL using a global aerosol microphysics model and aircraft and ground site observations made during the May 2008 campaign of the European Integrated Project on Aerosol Cloud Climate Air Quality Interactions (EUCAARI). We tested four different parameterisations for BL nucleation and two assumptions for the emission size distribution of anthropogenic and wildfire carbonaceous particles. When we emit carbonaceous particles at small sizes (as recommended by the Aerosol Intercomparison project, AEROCOM), the spatial distributions of campaign-mean number concentrations of particles with diameter >50 nm (N50) and >100 nm (N100) were well captured by the model (R2≥0.8) and the normalised mean bias (NMB) was also small (−18% for N50 and −1% for N100). Emission of carbonaceous particles at larger sizes, which we consider to be more realistic for low spatial resolution global models, results in equally good correlation but larger bias (R2≥0.8, NMB = −52% and −29%), which could be partly but not entirely compensated by BL nucleation. Within the uncertainty of the observations and accounting for the uncertainty in the size of emitted primary particles, BL nucleation makes a statistically significant contribution to CCN-sized particles at less than a quarter of the ground sites. Our results show that a major source of uncertainty in CCN-sized particles in polluted European air is the emitted size of primary carbonaceous particles. New information is required not just from direct observations, but also to determine the "effective emission size" and composition of primary particles appropriate for different resolution models.
01A - Beitrag in wissenschaftlicher Zeitschrift