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Franziska Schnell

Bio: Franziska Schnell is an academic researcher from Ludwig Maximilian University of Munich. The author has contributed to research in topics: Lidar & Volcano. The author has an hindex of 5, co-authored 7 publications receiving 118 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors show the four-dimensional (4-D) distribution of the Eyjafjallajokull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April-26 May 2010).
Abstract: . The eruption of the Icelandic volcano Eyjafjallajokull in April–May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET). Based on multi-wavelength Raman lidar systems, EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude. In this work we show the four-dimensional (4-D) distribution of the Eyjafjallajokull volcanic cloud in the troposphere over Europe as observed by EARLINET during the entire volcanic event (15 April–26 May 2010). All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio) are stored in the EARLINET database available at http://www.earlinet.org . A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org . During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the upper troposphere down to the local planetary boundary layer (PBL). After 19 April 2010, volcanic particles were detected over southern and south-eastern Europe. During the first half of May (5–15 May), material emitted by the Eyjafjallajokull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. The last observations of the event were recorded until 25 May in Central Europe and in the Eastern Mediterranean area. The 4-D distribution of volcanic aerosol layering and optical properties on European scale reported here provides an unprecedented data set for evaluating satellite data and aerosol dispersion models for this kind of volcanic events.

91 citations

DatasetDOI
Mariana Adam, Lucas Alados-Arboledas, Dietrich Althausen, Vassilis Amiridis, Aldo Amodeo, Albert Ansmann, Arnoud Apituley, Yuri Arshinov, Dimitris Balis, Livio Belegante, Sergey Bobrovnikov, Antonella Boselli, Juan Antonio Bravo-Aranda, Jens Bösenberg, Emil Carstea, A. Chaikovsky, Adolfo Comerón, Giuseppe D'Amico, David Daou, Tanja Dreischuh, Ronny Engelmann, Fanny Finger, Volker Freudenthaler, David Garcia-Vizcaino, Alfonso Javier Fernandez García, Alexander Geiß, E. Giannakaki, Helmuth Giehl, Aldo Giunta, Martin de Graaf, María José Granados-Muñoz, Matthias Grein, Ivan Grigorov, Silke Groß, Carsten Gruening, Juan Luis Guerrero-Rascado, Martial Haeffelin, Theresa Hayek, Marco Iarlori, Thomas Kanitz, Panayotis Kokkalis, Holger Linné, Fabio Madonna, Rodanthi-Elisavet Mamouri, Volker Matthias, Ina Mattis, Francisco Molero Menéndez, Valentin Mitev, Lucia Mona, Yohann Morille, Constantino Muñoz, Anja Müller, Detlef Müller, Francisco Navas-Guzmán, Anca Nemuc, Doina Nicolae, Marco Pandolfi, Alex Papayannis, Gelsomina Pappalardo, Jacques Pelon, Maria Rita Perrone, Aleksander Pietruczuk, Gianluca Pisani, Charlos Potma, Jana Preißler, Manuel Pujadas, Jean Putaud, Cristian Radu, Francois Ravetta, Andrew Reigert, Vincenzo Rizi, Francesc Rocadenbosch, Alejandro Rodríguez, Laurent Sauvage, Jörg Schmidt, Franziska Schnell, Anja Schwarz, Patric Seifert, Ilya Serikov, Michaël Sicard, Ana Maria Silva, Valentin Simeonov, Nikos Siomos, Tobias Sirch, Nicola Spinelli, Dimitar Stoyanov, Camelia Talianu, Matthias Tesche, Ferdinando De Tomasi, Thomas Trickl, Geraint Vaughan, Hester Volten, Frank Wagner, Ulla Wandinger, Xuan Wang, Matthias Wiegner, Keith M. Wilson 
13 Nov 2013

7 citations

DatasetDOI
Mariana Adam, Lucas Alados-Arboledas, Dietrich Althausen, Amiridis, Aldo Amodeo, Albert Ansmann, Arnoud Apituley, Yuri Arshinov, Dimitris Balis, Livio Belegante, Sergey Bobrovnikov, Antonella Boselli, Juan Antonio Bravo-Aranda, Jens Bösenberg, Emil Carstea, A. Chaikovsky, Adolfo Comerón, Giuseppe D'Amico, David Daou, Tanja Dreischuh, Ronny Engelmann, Fanny Finger, Volker Freudenthaler, David Garcia-Vizcaino, Alfonso Javier Fernandez García, Alexander Geiss, E. Giannakaki, Helmuth Giehl, Aldo Giunta, Martin de Graaf, María José Granados-Muñoz, Matthias Grein, Ivan Grigorov, Silke Gross, Carsten Gruening, Juan Luis Guerrero-Rascado, Martial Haeffelin, Theresa Hayek, Marco Iarlori, Thomas Kanitz, Panayotis Kokkalis, Holger Linné, Fabio Madonna, Rodanthi-Elisavet Mamouriat, Volker Matthias, Ina Mattis, Francisco Molero Menéndez, Valentin Mitev, Lucia Mona, Yohann Morille, Constantino Muñoz, Anja Müller, Detlef Müller, Francisco Navas-Guzmán, Anca Nemuc, Doina Nicolae, Marco Pandolfi, Alex Papayannis, Gelsomina Pappalardo, Jacques Pelon, Maria Rita Perrone, Aleksander Pietruczuk, Gianluca Pisani, Charlos Potma, Jana Preissler, Manuel Pujadas, Jean Putaud, Cristian Radu, Francois Ravetta, Andrew Reigert, Vincenzo Rizi, Francesc Rocadenbosch, Alejandro Rodríguez, Laurent Sauvage, Jörg Schmidt, Franziska Schnell, Anja Schwarz, Patric Seifert, Ilya Serikov, Michaël Sicard, Ana Maria Silva, Valentin Simeonov, Nikos Siomos, Tobias Sirch, Nicola Spinelli, Dimitar Stoyanov, Camelia Talianu, Matthias Tesche, Ferdinando De Tomasi, Thomas Trickl, Geraint Vaughan, Hester Volten, Frank Wagner, Ulla Wandinger, Xuan Wang, Matthias Wiegner, Keith M. Wilson 
25 Feb 2014

7 citations

DatasetDOI
Mariana Adam, Lucas Alados-Arboledas, Dietrich Althausen, Vassilis Amiridis, Aldo Amodeo, Albert Ansmann, Arnoud Apituley, Yuri Arshinov, Dimitris Balis, Livio Belegante, Sergey Bobrovnikov, Antonella Boselli, Juan Antonio Bravo-Aranda, Jens Bösenberg, Emil Carstea, A. Chaikovsky, Adolfo Comerón, Giuseppe D'Amico, David Daou, Tanja Dreischuh, Ronny Engelmann, Fanny Finger, Volker Freudenthaler, David Garcia-Vizcaino, Alfonso Javier Fernandez García, Alexander Geiß, E. Giannakaki, Helmuth Giehl, Aldo Giunta, Martin de Graaf, María José Granados-Muñoz, Matthias Grein, Ivan Grigorov, Silke Groß, Carsten Gruening, Juan Luis Guerrero-Rascado, Martial Haeffelin, Theresa Hayek, Marco Iarlori, Thomas Kanitz, Panayotis Kokkalis, Holger Linné, Fabio Madonna, Rodanthi-Elisavet Mamouri, Volker Matthias, Ina Mattis, Francisco Molero Menéndez, Valentin Mitev, Lucia Mona, Yohann Morille, Constantino Muñoz, Anja Müller, Detlef Müller, Francisco Navas-Guzmán, Anca Nemuc, Doina Nicolae, Marco Pandolfi, Alex Papayannis, Gelsomina Pappalardo, Jacques Pelon, Maria Rita Perrone, Aleksander Pietruczuk, Gianluca Pisani, Charlos Potma, Jana Preißler, Manuel Pujadas, Jean Putaud, Cristian Radu, Francois Ravetta, Andrew Reigert, Vincenzo Rizi, Francesc Rocadenbosch, Alejandro Rodríguez, Laurent Sauvage, Jörg Schmidt, Franziska Schnell, Anja Schwarz, Patric Seifert, Ilya Serikov, Michaël Sicard, Ana Maria Silva, Valentin Simeonov, Nikos Siomos, Tobias Sirch, Nicola Spinelli, Dimitar Stoyanov, Camelia Talianu, Matthias Tesche, Ferdinando De Tomasi, Thomas Trickl, Geraint Vaughan, Hester Volten, Frank Wagner, Ulla Wandinger, Xuan Wang, Matthias Wiegner, Keith M. Wilson 
01 Jan 2014

7 citations

DatasetDOI
Mariana Adam, Lucas Alados-Arboledas, Dietrich Althausen, Vassilis Amiridis, Aldo Amodeo, Albert Ansmann, Arnoud Apituley, Yuri Arshinov, Dimitris Balis, Livio Belegante, Sergey Bobrovnikov, Antonella Boselli, Juan Antonio Bravo-Aranda, Jens Bösenberg, Emil Carstea, A. Chaikovsky, Adolfo Comerón, Giuseppe D'Amico, David Daou, Tanja Dreischuh, Ronny Engelmann, Fanny Finger, Volker Freudenthaler, David Garcia-Vizcaino, Alfonso Javier Fernandez García, Alexander Geiß, E. Giannakaki, Helmuth Giehl, Aldo Giunta, Martin de Graaf, María José Granados-Muñoz, Matthias Grein, Ivan Grigorov, Silke Groß, Carsten Gruening, Juan Luis Guerrero-Rascado, Martial Haeffelin, Theresa Hayek, Marco Iarlori, Thomas Kanitz, Panayotis Kokkalis, Holger Linné, Fabio Madonna, Rodanthi-Elisavet Mamouri, Volker Matthias, Ina Mattis, Francisco Molero Menéndez, Valentin Mitev, Lucia Mona, Yohann Morille, Constantino Muñoz, Anja Müller, Detlef Müller, Francisco Navas-Guzmán, Anca Nemuc, Doina Nicolae, Marco Pandolfi, Alex Papayannis, Gelsomina Pappalardo, Jacques Pelon, Maria Rita Perrone, Aleksander Pietruczuk, Gianluca Pisani, Charlos Potma, Jana Preißler, Manuel Pujadas, Jean Putaud, Cristian Radu, Francois Ravetta, Andrew Reigert, Vincenzo Rizi, Francesc Rocadenbosch, Alejandro Rodríguez, Laurent Sauvage, Jörg Schmidt, Franziska Schnell, Anja Schwarz, Patric Seifert, Ilya Serikov, Michaël Sicard, Ana Maria Silva, Valentin Simeonov, Nikos Siomos, Tobias Sirch, Nicola Spinelli, Dimitar Stoyanov, Camelia Talianu, Matthias Tesche, Ferdinando De Tomasi, Thomas Trickl, Geraint Vaughan, Hester Volten, Frank Wagner, Ulla Wandinger, Xuan Wang, Matthias Wiegner, Keith M. Wilson 
13 Nov 2013

7 citations


Cited by
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Journal ArticleDOI
TL;DR: The European Aerosol Research Lidar Network (EARLINET) as mentioned in this paper was founded as a research project for establishing a quantitative, comprehensive, and statistically significant database for the horizontal, vertical, and tempo-ral distribution of aerosols on a continental scale.
Abstract: The European Aerosol Research Lidar Network, EARLINET, was founded in 2000 as a research project for establishing a quantitative, comprehensive, and statistically significant database for the horizontal, vertical, and tempo- ral distribution of aerosols on a continental scale. Since then EARLINET has continued to provide the most extensive col- lection of ground-based data for the aerosol vertical distribu- tion over Europe. This paper gives an overview of the network's main de- velopments since 2000 and introduces the dedicated EAR- LINET special issue, which reports on the present innova- tive and comprehensive technical solutions and scientific re- sults related to the use of advanced lidar remote sensing tech- niques for the study of aerosol properties as developed within the network in the last 13 years. Since 2000, EARLINET has developed greatly in terms of number of stations and spatial distribution: from 17 sta- tions in 10 countries in 2000 to 27 stations in 16 countries in 2013. EARLINET has developed greatly also in terms of technological advances with the spread of advanced multi- wavelength Raman lidar stations in Europe. The develop- ments for the quality assurance strategy, the optimization of instruments and data processing, and the dissemination of data have contributed to a significant improvement of the net- work towards a more sustainable observing system, with an increase in the observing capability and a reduction of oper- ational costs. Consequently, EARLINET data have already been ex- tensively used for many climatological studies, long-range transport events, Saharan dust outbreaks, plumes from vol- canic eruptions, and for model evaluation and satellite data validation and integration. Future plans are aimed at continuous measurements and near-real-time data delivery in close cooperation with other ground-based networks, such as in the ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) www.actris.net, and with the modeling and satellite commu- nity, linking the research community with the operational world, with the aim of establishing of the atmospheric part of the European component of the integrated global observ- ing system.

417 citations

Journal ArticleDOI
TL;DR: In this paper, different retrieval methods to derive the aerosol backscatter coefficient βp, with special focus on the calibration of the ceilometers, are compared with respect to their accuracy and applicability, and it is shown that advanced lidar systems such as those being operated in the framework of the European Aerosol Research Lidar Network (EARLINET) are excellent tools for the calibration.
Abstract: . With the establishment of ceilometer networks by national weather services, a discussion commenced to which extent these simple backscatter lidars can be used for aerosol research. Though primarily designed for the detection of clouds it was shown that at least observations of the vertical structure of the boundary layer might be possible. However, an assessment of the potential of ceilometers for the quantitative retrieval of aerosol properties is still missing. In this paper we discuss different retrieval methods to derive the aerosol backscatter coefficient βp, with special focus on the calibration of the ceilometers. Different options based on forward and backward integration methods are compared with respect to their accuracy and applicability. It is shown that advanced lidar systems such as those being operated in the framework of the European Aerosol Research Lidar Network (EARLINET) are excellent tools for the calibration, and thus βp retrievals based on forward integration can readily be implemented and used for real-time applications. Furthermore, we discuss uncertainties introduced by incomplete overlap, the unknown lidar ratio, and water vapor absorption. The latter is relevant for the very large number of ceilometers operating in the spectral range around λ = 905–910 nm. The accuracy of the retrieved βp mainly depends on the accuracy of the calibration and the long-term stability of the ceilometer. Under favorable conditions, a relative error of βp on the order of 10% seems feasible. In the case of water vapor absorption, corrections assuming a realistic water vapor distribution and laser spectrum are indispensable; otherwise errors on the order of 20% could occur. From case studies it is shown that ceilometers can be used for the reliable detection of elevated aerosol layers below 5 km, and can contribute to the validation of chemistry transport models, e.g., the height of the boundary layer. However, the exploitation of ceilometer measurements is still in its infancy, so more studies are urgently needed to consolidate the present state of knowledge, which is based on a limited number of case studies.

151 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a new dust product developed using CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) observations and methods to provide a 3D multi-year analysis on the evolution of Saharan dust over North Africa and Europe.
Abstract: . In this study we use a new dust product developed using CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) observations and EARLINET (European Aerosol Research Lidar Network) measurements and methods to provide a 3-D multiyear analysis on the evolution of Saharan dust over North Africa and Europe. The product uses a CALIPSO L2 backscatter product corrected with a depolarization-based method to separate pure dust in external aerosol mixtures and a Saharan dust lidar ratio (LR) based on long-term EARLINET measurements to calculate the dust extinction profiles. The methodology is applied on a 9-year CALIPSO dataset (2007–2015) and the results are analyzed here to reveal for the first time the 3-D dust evolution and the seasonal patterns of dust over its transportation paths from the Sahara towards the Mediterranean and Continental Europe. During spring, the spatial distribution of dust shows a uniform pattern over the Sahara desert. The dust transport over the Mediterranean Sea results in mean dust optical depth (DOD) values up to 0.1. During summer, the dust activity is mostly shifted to the western part of the desert where mean DOD near the source is up to 0.6. Elevated dust plumes with mean extinction values between 10 and 75 Mm−1 are observed throughout the year at various heights between 2 and 6 km, extending up to latitudes of 40° N. Dust advection is identified even at latitudes of about 60° N, but this is due to rare events of episodic nature. Dust plumes of high DOD are also observed above the Balkans during the winter period and above northwest Europe during autumn at heights between 2 and 4 km, reaching mean extinction values up to 50 Mm−1. The dataset is considered unique with respect to its potential applications, including the evaluation of dust transport models and the estimation of cloud condensation nuclei (CCN) and ice nuclei (IN) concentration profiles. Finally, the product can be used to study dust dynamics during transportation, since it is capable of revealing even fine dynamical features such as the particle uplifting and deposition on European mountainous ridges such as the Alps and Carpathian Mountains.

120 citations

Journal ArticleDOI
TL;DR: The LIVAS database as mentioned in this paper provides averaged profiles of aerosol optical properties for the potential spaceborne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm.
Abstract: . We present LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies), a 3-D multi-wavelength global aerosol and cloud optical database, optimized to be used for future space-based lidar end-to-end simulations of realistic atmospheric scenarios as well as retrieval algorithm testing activities. The LIVAS database provides averaged profiles of aerosol optical properties for the potential spaceborne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm. The global database is based on CALIPSO observations at 532 and 1064 nm and on aerosol-type-dependent backscatter- and extinction-related Angstrom exponents, derived from EARLINET (European Aerosol Research Lidar Network) ground-based measurements for the UV and scattering calculations for the IR wavelengths, using a combination of input data from AERONET, suitable aerosol models and recent literature. The required spectral conversions are calculated for each of the CALIPSO aerosol types and are applied to CALIPSO backscatter and extinction data corresponding to the aerosol type retrieved by the CALIPSO aerosol classification scheme. A cloud optical database based on CALIPSO measurements at 532 nm is also provided, neglecting wavelength conversion due to approximately neutral scattering behavior of clouds along the spectral range of LIVAS. Averages of particle linear depolarization ratio profiles at 532 nm are provided as well. Finally, vertical distributions for a set of selected scenes of specific atmospheric phenomena (e.g., dust outbreaks, volcanic eruptions, wild fires, polar stratospheric clouds) are analyzed and spectrally converted so as to be used as case studies for spaceborne lidar performance assessments. The final global data set includes 4-year (1 January 2008–31 December 2011) time-averaged CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) data on a uniform grid of 1° × 1° with the original high vertical resolution of CALIPSO in order to ensure realistic simulations of the atmospheric variability in lidar end-to-end simulations.

96 citations

Journal ArticleDOI
Abstract: . Systematic measurements of dust concentration profiles at a continental scale were recently made possible by the development of synergistic retrieval algorithms using combined lidar and sun photometer data and the establishment of robust remote-sensing networks in the framework of Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS)/European Aerosol Research Lidar Network (EARLINET). We present a methodology for using these capabilities as a tool for examining the performance of dust transport models. The methodology includes considerations for the selection of a suitable data set and appropriate metrics for the exploration of the results. The approach is demonstrated for four regional dust transport models (BSC-DREAM8b v2, NMMB/BSC-DUST, DREAMABOL, DREAM8-NMME-MACC) using dust observations performed at 10 ACTRIS/EARLINET stations. The observations, which include coincident multi-wavelength lidar and sun photometer measurements, were processed with the Lidar-Radiometer Inversion Code (LIRIC) to retrieve aerosol concentration profiles. The methodology proposed here shows advantages when compared to traditional evaluation techniques that utilize separately the available measurements such as separating the contribution of dust from other aerosol types on the lidar profiles and avoiding model assumptions related to the conversion of concentration fields to aerosol extinction values. When compared to LIRIC retrievals, the simulated dust vertical structures were found to be in good agreement for all models with correlation values between 0.5 and 0.7 in the 1–6 km range, where most dust is typically observed. The absolute dust concentration was typically underestimated with mean bias values of -40 to -20 μg m−3 at 2 km, the altitude of maximum mean concentration. The reported differences among the models found in this comparison indicate the benefit of the systematic use of the proposed approach in future dust model evaluation studies.

81 citations