Frank Wagner

Bio: Frank Wagner is an academic researcher from University of Évora. The author has contributed to research in topics: Aerosol & Lidar. The author has an hindex of 22, co-authored 56 publications receiving 1570 citations. Previous affiliations of Frank Wagner include Ludwig Maximilian University of Munich.

Optical properties of the Indo-Asian haze layer over the tropical Indian Ocean

Abstract: [1] Multiwavelength backscatter and extinction profiling was performed with a unique aerosol Raman lidar at Hulhule (4� N, 73� E), Maldives, as part of the Indian Ocean Experiment (INDOEX) between February 1999 and March 2000. The Raman lidar allowed a direct determination of the volume extinction coefficient of the particles at 355 and 532 nm at ambient conditions. Heavily polluted air masses from the Asian continent passed over the Maldives during the northeast monsoon seasons. The mean 532-nm particle optical depth was about 0.3; maximum values of 0.7 were measured. Above the polluted marine boundary layer, lofted plumes were found up to 4000-m height. On average, the freetropospheric aerosol layers contributed 30–60% to the particle optical depth. The volume extinction coefficient at 532 nm typically ranged from 25 to 175 Mm � 1 in the elevated layers. The pollution plumes are characterized separately for the air masses from Southeast Asia, North India, and South India. The analysis includes backward trajectories and emission inventory data for India. The extinction-to-backscatter ratio (lidar ratio) at 532 nm was mostly between 30 and 100 sr, and accumulated at 50–80 sr for highly absorbing particles from northern India. The shift of the lidar-ratio distribution for northern Indian aerosols by about 20 sr toward larger values compared to European values is consistent

Vertical profiling of the Indian aerosol plume with six-wavelength lidar during INDOEX : A first case study

Abstract: . tation of data from ground-based and space-based ra- During the Intensive Field Phase (IFP) of the Indian diometers. In Section 2 the INDOEX lidar station at Ocean Experiment (INDOEX) lasting from 15 February Hulule is described. The observations of the aerosol to 26 March 1999, a large number of pollution outbreaks optical properties are discussed in Section 3. from India and southeast Asia were observed with a unique six-wavelength aerosol lidar at Maldives Inter- national Airport, Hulule (4.1° N, 73.3O E). An example 2. Apparatus is presented here. Above the polluted marine boundary layer a 3-km deep aerosol layer was advected from the A brief summary of the advanced aerosol lidar [Alt- Indian subcontinent. The aerosol optical depths of the ’ hausen et al., 19991 is given here. Two Nd:YAG and two marine boundary layer and the free-troposphere layer dye lasers serve as radiation sources at 355, 400, 532, were approximately 0.2 and 0.4 at 532 nm, respectively. 710,800, and 1064nm. A beam combination unit aligns Inversions using spectrally resolved particle backscatter all six laser beams onto one optical axis. The com- and extinction data indicate an effective particle radius bined beam can then be directed into the atmosphere of 0.17 pm, volume and surface concentrations around into any zenith angle between -90° and 90° by means 13 pm3 cmm3 and 600 pm2 cme3, respectively, and con- of a steerable mirror. In addition to the return signals siderable absorption by the free-tropospheric particles. elastically backscattered by air molecules and particles at the laser wavelengths, Raman signals from nitro- gen molecules are detected at 387 nm (355 nm primary

Properties of dust aerosol particles transported to Portugal from the Sahara desert

Abstract: Aerosol properties of mineral particles in the far field of an African desert dust outbreak were investigated that brought Saharan dust over the Mediterranean in different layers to Portugal. The measurements were performed inside the project Desert Aerosols over Portugal (DARPO) which was linked to the Saharan Mineral Dust Experiment (SAMUM). The maximum particle mass concentration was about 150 μg m -3 and the corresponding scattering coefficient was 130 M m -1 which results in a mass scattering efficiency of 0.87 m 2 g -1 . The aerosol optical depth reached values up to 0.53 and the lidar ratio was between 45 and 50 in the whole dust loaded column. A comparison between particle size distributions and refractive indices derived from different instruments and models showed a general good agreement but some minor differences could also be observed. Measurements as well as calculations with a particle transport model suggest that there is a relatively higher concentration of very large particles in the upper region of the dust layer than on the surface which is likely connected with meteorological conditions at the observational site (Evora, Portugal). DOI: 10.1111/j.1600-0889.2008.00393.x

Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

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.

European pollution outbreaks during ACE 2: Optical particle properties inferred from multiwavelength lidar and star-Sun photometry

Abstract: (1) On the basis of multiwavelength backscatter and 532-nm extinction profiling with lidar at Sagres (37� N, 9� W), southern Portugal, and optical depth observations with a star photometer at the lidar site and a Sun photometer atop a nearby mountain, several European pollution outbreaks were characterized during the Second Aerosol Characterization Experiment (ACE 2) in the summer of 1997. A sophisticated analysis scheme applied to the lidar-photometer data set is described. The observations are mainly presented in terms of profiles of the 532-nm extinction-to-backscatter ratio (lidar ratio) and of A u ngstrom exponents calculated for the wavelength ranges 400-532 nm and 532-800 nm. The lidar ratio indicates the aerosol type (marine, soil, pollution) whereas the A u ngstrom exponents are sensitive to changes in the particle size distribution (accumulation mode, coarse mode). Results of an extensive correlation analysis considering all determined optical parameters, relative humidity, and measurement height are discussed. Finally, the spectrally resolved optical depth and the column A u ngstrom exponents for the lofted outbreak plumes determined from the lidar profiles are compared with respective values derived from the star and Sun photometer measurements. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0345 Atmospheric Composition and Structure: Pollution— urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry; 1630 Global Change: Impact phenomena; KEYWORDS: multiwavelength lidar, star photometer, Sun photometer, anthropogenic aerosols, aerosol optical properties

The CALIPSO Automated Aerosol Classification and Lidar Ratio Selection Algorithm

Abstract: Descriptions are provided of the aerosol classification algorithms and the extinction-to-backscatter ratio (lidar ratio) selection schemes for the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) aerosol products One year of CALIPSO level 2 version 2 data are analyzed to assess the veracity of the CALIPSO aerosol-type identification algorithm and generate vertically resolved distributions of aerosol types and their respective optical characteristics To assess the robustness of the algorithm, the interannual variability is analyzed by using a fixed season (June–August) and aerosol type (polluted dust) over two consecutive years (2006 and 2007) The CALIPSO models define six aerosol types: clean continental, clean marine, dust, polluted continental, polluted dust, and smoke, with 532-nm (1064 nm) extinction-to-backscatter ratios Sa of 35 (30), 20 (45), 40 (55), 70 (30), 65 (30), and 70 (40) sr, respectively This paper presents the global distributions of the CALIPSO a

Residential Biofuels in South Asia: Carbonaceous Aerosol Emissions and Climate Impacts

Abstract: High concentrations of pollution particles, including "soot" or black carbon, exist over the Indian Ocean, but their sources and geographical origins are not well understood. We measured emissions from the combustion of biofuels, used widely in south Asia for cooking, and found that large amounts of carbonaceous aerosols are emitted per kilogram of fuel burnt. We calculate that biofuel combustion is the largest source of black carbon emissions in India, and we suggest that its control is central to climate change mitigation in the south Asian region.

Investigation of the sources and evolution processes of severe haze pollution in Beijing in January 2013

Abstract: China experienced severe haze pollution in January 2013. Here we have a detailed characterization of the sources and evolution mechanisms of this haze pollution with a focus on four haze episodes that occurred during 10–14 January in Beijing. The main source of data analyzed is from submicron aerosol measurements by an Aerodyne Aerosol Chemical Speciation Monitor. The average PM1 mass concentration during the four haze episodes ranged from 144 to 300 µg m−3, which was more than 10 times higher than that observed during clean periods. All submicron aerosol species showed substantial increases during haze episodes with sulfate being the largest. Secondary inorganic species played enhanced roles in the haze formation as suggested by their elevated contributions during haze episodes. Positive matrix factorization analysis resolved six organic aerosol (OA) factors including three primary OA (POA) factors from traffic, cooking, and coal combustion emissions, respectively, and three secondary OA (SOA) factors. Overall, SOA contributed 41–59% of OA with the rest being POA. Coal combustion OA (CCOA) was the largest primary source, on average accounting for 20–32% of OA, and showed the most significant enhancement during haze episodes. A regional SOA (RSOA) was resolved for the first time which showed a pronounced peak only during the record-breaking haze episode (Ep3) on 12–13 January. The regional contributions estimated based on the steep evolution of air pollutants were found to play dominant roles for the formation of Ep3, on average accounting for 66% of PM1 during the peak of Ep3 with sulfate, CCOA, and RSOA being the largest fractions (> ~ 75%). Our results suggest that stagnant meteorological conditions, coal combustion, secondary production, and regional transport are four main factors driving the formation and evolution of haze pollution in Beijing during wintertime.