In situ physical and chemical characterisation of the Eyjafjallajökull aerosol plume in the free troposphere over Italy

Sandrini, Silvia; Giulianelli, L.; Decesari, Stefano; Fuzzi, S.; Cristofanelli, Paolo; Marinoni, Angela; Bonasoni, Paolo; Chiari, M.; Calzolai, Giulia; Canepari, Silvia; Perrino, Cinzia; Facchini, M. C.

doi:10.5194/acp-14-1075-2014

Cited by 13 publications

(10 citation statements)

References 61 publications

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“…The volcanic plume resulting from that eruption was observed at CMN (Sandrini et al 2014), KVV (Beeston et al 2012), ZSF (Flentje et al 2010;Schäfer et al 2011), and JFJ (Bukowiecki et al 2011). Moreover, enhanced PM 10 and SO 2 concentrations were observed at ZSF and JFJ.…”

Section: Dust and Volcanic Emissionsmentioning

confidence: 93%

A review of atmospheric chemistry observations at mountain sites

Okamoto

Tanimoto

2016

Prog. in Earth and Planet. Sci.

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Located far from anthropogenic emission sources, high-altitude mountain stations are considered to be ideal sites for monitoring climatic and environmentally important baseline changes in free tropospheric trace gases and aerosols. In addition, the observations taken at these stations are often used to study the long-range transport of dust as well as anthropogenic and biomass burning pollutants from source regions and to evaluate the performance of global and regional models. In this paper, we summarize the results from past and ongoing field measurements of atmospheric constituents at high-altitude stations across the globe, with particular emphasis on reactive trace species including tropospheric ozone, along with its precursors such as carbon monoxide, nitrogen oxides, total reactive nitrogen, and nonmethane hydrocarbons. Over the past decades, our understanding of the temporal variability and meteorological mechanisms of long-range transport has advanced in tandem with progress in instrumentation and modeling. Finally, the future needs of atmospheric chemistry observations at mountain sites are addressed.

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Section: Dust and Volcanic Emissionsmentioning

confidence: 93%

A review of atmospheric chemistry observations at mountain sites

Okamoto

Tanimoto

2016

Prog. in Earth and Planet. Sci.

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“…In spring 2010, an eruption of the volcano Eyjafjallajökull in Iceland lead to a closure of the European air space for several days (Sandrini et al, 2014). Due to its impact on public transport and on the transport of goods, this case was extensively analyzed by scientists from many fields of research, resulting in a substantial knowledge base (see ACP special issue "Atmospheric impli-…”

Section: Selection and Descriptionmentioning

confidence: 99%

A Backscatter Lidar Forward Operator for Particle-Representing Atmospheric Chemistry Models

Geisinger

Behrendt

Wulfmeyer

et al. 2016

Preprint

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Abstract.State-of-the-art atmospheric chemistry models are capable of simulating the transport and evolution of particles and trace gases but there is a lack of reliable methods for model validation and data assimilation. Networks of automated ceilometer lidar systems (ACLs) could be used to fill this gap. These are already used for the detection of clouds and aerosols, providing a 3D dataset of atmospheric backscatter profiles. However, as the aerosol number concentration cannot be obtained from the ACL 5 data alone, one needs a backscatter-lidar forward model to simulate lidar profiles from the model variables. Such an operator allows then for a qualitative and quantitative model validation based on ACL data. In this work, we present a new backscatterlidar operator which contains most of the microphysical properties of aerosol particles, discuss sensitivity studies and compare simulated with measured ACL profiles. A major challenge is the high sensitivity of the optical cross sections to the particle size and shape: A slightly different particle radius may lead to quite a large change of the scattering properties. As most particle 10 size distributions are continuous in reality, the optical cross sections are averaged over certain size-intervals which also reduces the problematic and unrealistic sensitivity significantly. To calculate the attenuated backscatter coefficient, the size-dependent particle number concentration and the scattering properties of each particle type and size have to be simulated. While the particle number concentration is a model output variable, the scattering properties have to be determined by extensive scattering calculations. As these scattering calculations require assumptions about the particle refractive indices and shapes, sensitivity 15 studies were performed to estimate the uncertainties related to the particle properties as represented by the model system.The strong sensitivity of the scattering characteristics to the particle radius was largely reduced by size-averaging algorithms.We focus on a case study of the eruption of the Islandic volcano Eyjafjallajökull from 20 March 2010 to 24 May 2010. The Consortium for Small-scale Modeling -Aerosols and Reactive Trace gases (COSMO-ART) model of DWD (Deutscher Wetterdienst) and KIT (Karlsruhe Institute of Technology) was used during this event for ash-dispersion simulation over Europe. 20For the forward model, the attenuated backscatter coefficient is used as lidar-independent variable, as it only relies on the laser wavelength. Finally, the forward modeled lidar profiles were compared to ACL measurements. Significant differences between ACL profiles and the output of the forward operator applied to the COSMO-ART data were found but also several identical features have been observed. Comparing the data quantitatively revealed that the model-predicted ash number concentration is slightly too high. We identified the following key issues which are mandatory for performing quantitative comparisons be-

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“…The emitted ash was found to be harmful for aircraft, and due to uncertain information about spatial distribution and concentration of volcanic ash, the European air space was closed for several days (Sandrini et al, 2014). The high economic costs and impact on public transport led to efforts of DWD (Deutscher Wetterdienst) to improve monitoring and predicting ash plumes in the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Development and application of a backscatter lidar forward operator for quantitative validation of aerosol dispersion models and future data assimilation

et al. 2017

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Abstract.A new backscatter lidar forward operator was developed which is based on the distinct calculation of the aerosols' backscatter and extinction properties. The forward operator was adapted to the COSMO-ART ash dispersion simulation of the Eyjafjallajökull eruption in 2010. While the particle number concentration was provided as a model output variable, the scattering properties of each individual particle type were determined by dedicated scattering calculations. Sensitivity studies were performed to estimate the uncertainties related to the assumed particle properties. Scattering calculations for several types of non-spherical particles required the usage of T-matrix routines. Due to the distinct calculation of the backscatter and extinction properties of the models' volcanic ash size classes, the sensitivity studies could be made for each size class individually, which is not the case for forward models based on a fixed lidar ratio. Finally, the forward-modeled lidar profiles have been compared to automated ceilometer lidar (ACL) measurements both qualitatively and quantitatively while the attenuated backscatter coefficient was chosen as a suitable physical quantity. As the ACL measurements were not calibrated automatically, their calibration had to be performed using satellite lidar and ground-based Raman lidar measurements. A slight overestimation of the model-predicted volcanic ash number density was observed. Major requirements for future data assimilation of data from ACL have been identified, namely, the availability of calibrated lidar measurement data, a scattering database for atmospheric aerosols, a better representation and coverage of aerosols by the ash dispersion model, and more investigation in backscatter lidar forward operators which calculate the backscatter coefficient directly for each individual aerosol type. The introduced forward operator offers the flexibility to be adapted to a multitude of model systems and measurement setups.

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In situ physical and chemical characterisation of the Eyjafjallajökull aerosol plume in the free troposphere over Italy

Cited by 13 publications

References 61 publications

A review of atmospheric chemistry observations at mountain sites

A review of atmospheric chemistry observations at mountain sites

A Backscatter Lidar Forward Operator for Particle-Representing Atmospheric Chemistry Models

Development and application of a backscatter lidar forward operator for quantitative validation of aerosol dispersion models and future data assimilation

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