Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


11 - 20 / 21
Na začetekNa prejšnjo stran123Na naslednjo stranNa konec
11.
12.
Vertical profiling of aerosol properties with two-wavelength polarization Raman lidar over the Vipava valley
William Eichinger, Klemen Bergant, Griša Močnik, Luka Drinovec, Samo Stamoč, Asta Gregorič, Longlong Wang, 2018, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Presence of atmospheric aerosols affects the Earth’s radiation budget and thus also atmospheric thermal structure, which in turn affects cloud and planetary boundary layer (PBL) dynamics. We combine in-situ and remote measurements to determine aerosol properties in a representative hot-spot for air pollution in a complex terrain configuration. Vertical profiles of aerosol properties were investigated using a two-wavelength polarization Raman lidar system in the Vipava valley. Using lidar-obtained particle depolarization ratio, lidar ratio and backscatter Ångström exponent (355 nm / 1064 nm), which depend on aerosol shape, size and refractive index, thus the aerosols can be identified and the roles of different aerosol types in the observed atmospheric processes were investigated. In addition, aerosol absorption coefficients were measured in-situ by Aethalometers (AE33, Magee Scientific / Aerosol d.o.o.) on the valley floor and on the adjacent mountain range, 850 m above the lidar site. Our primary goal was to study the variability of aerosol types within and above the Vipava valley, which was performed using the entire lidar dataset from August – December 2017. Primary anthropogenic aerosols within the valley is mainly emitted from two sources: individual domestic heating systems, which mostly use biomass fuel and traffic. Natural aerosols, transported by long-range transport, such as mineral dust and sea salt, were observed both above the PBL and entering into the PBL. Vertical distributions of aerosol properties, in par- ticular the particle depolarization ratio, indicated atmospheric stratification with different aerosol types occupying different height ranges. In the presence of Bora (strong down-slope wind), Kelvin-Helmholtz instabilities were observed between the PBL and the free troposphere. Using aerosol type identification capability of our system, we discovered that this instability was responsible for ejecting aerosols from the PBL up to 2 km into the free troposphere. In addition, we improved the reliability of aerosol identification in vertical profiles using absorption coeffi- cient measured by Aethalometer. Combining it with the aerosol extinction coefficient at 355 nm derived from lidar data, we derived aerosol single scattering albedo (SSA), which is an important parameter for aerosol characterization.
Najdeno v: osebi
Ključne besede: Aerosol, Vipava valley, lidar
Objavljeno: 23.04.2018; Ogledov: 2066; Prenosov: 0
.pdf Polno besedilo (35,82 KB)

13.
Efficient traffic regulation based on urban Black Carbon measurements and prediction model
Asta Gregorič, Luka Drinovec, Griša Močnik, Anja Barle, Matija Marolt, Jernej Henigman, Borut Šuštar, Mitja Ferlan, Andrej Pangeršič, 2018, objavljeni povzetek znanstvenega prispevka na konferenci

Najdeno v: osebi
Ključne besede: air quality, black carbon
Objavljeno: 29.10.2018; Ogledov: 1522; Prenosov: 0
.pdf Polno besedilo (568,01 KB)

14.
PHOTO-THERMAL INTERFEROMETER
Griša Močnik, Luka Drinovec, patent

Opis: A photo-thermal interferometer for measuring the light absorption of an aerosol or gas comprises a first laser source emitting a laser beam and a beam splitter adapted to divide the laser beam into a probe beam and a reference beam. The interferometer further comprises first optical elements which are adapted to direct the probe beam such that it passes through the aerosol and interferes with the reference beam thereafter thereby causing interference patterns. A detector detects the interference patterns. The interferometer further comprises a second laser source configured to emit a pump beam for transferring energy to the aerosol. Second optical elements are adapted to direct the pump beam such that it overlaps with the probe beam at least partially in the aerosol or gas. At least one of the second optical elements modifying the pump beam is an axicon.
Najdeno v: osebi
Ključne besede: absorption, aerosol, black carbon
Objavljeno: 30.04.2020; Ogledov: 803; Prenosov: 34
.pdf Polno besedilo (539,62 KB)

15.
A new optical-based technique for real-time measurements of mineral dust concentration in PM10 using a virtual impactor
Luka Drinovec, Jean Sciare, Iasonas Stavroulas, S. Bezantakos, Michael Pikridas, Florin Unga, Chrysanthos Savvides, Bojana Višnjić, Maja Remškar, Griša Močnik, 2020, izvirni znanstveni članek

Opis: Atmospheric mineral dust influences Earth’s radiative budget, cloud formation, and lifetime; has adverse health effects; and affects air quality through the increase of regulatory PM10 concentrations, making its real-time quantification in the atmosphere of strategic importance. Only few near-real-time techniques can discriminate dust aerosol in PM10 samples and they are based on the dust chemical composition. The online determination of mineral dust using aerosol absorption photometers offers an interesting and competitive alternative but remains a difficult task to achieve. This is particularly challenging when dust is mixed with black carbon, which features a much higher mass absorption cross section. We build on previous work using filter photometers and present here for the first time a highly timeresolved online technique for quantification of mineral dust concentration by coupling a high-flow virtual impactor (VI) sampler that concentrates coarse particles with an aerosol absorption photometer (Aethalometer, model AE33). The absorption of concentrated dust particles is obtained by subtracting the absorption of the submicron (PM1) aerosol fraction from the absorption of the virtual impactor sample (VIPM1 method). This real-time method for detecting desert dust was tested in the field for a period of 2 months (April and May 2016) at a regional background site of Cyprus, in the Eastern Mediterranean. Several intense desert mineral dust events were observed during the field campaign with dust concentration in PM10 up to 45 μgm
Najdeno v: osebi
Ključne besede: aerosol absorption, mineral dust, on-line detection, air quality
Objavljeno: 20.07.2020; Ogledov: 556; Prenosov: 0
.pdf Polno besedilo (2,38 MB)

16.
The new instrument using a TC–BC (total carbon–black carbon) method for the online measurement of carbonaceous aerosols
Martin Rigler, Luka Drinovec, Gašper Lavrič, Anastasia Vlachou, Andre S. H. Prevot, Jean-Luc Jaffrezo, Iasonas Stavroulas, Jean Sciare, Judita Burger, Irena Krajnc, Janja Turšič, Anthony D. A. Hansen, Griša Močnik, 2020, izvirni znanstveni članek

Opis: We present a newly developed total carbon analyzer (TCA08) and a method for online speciation of carbonaceous aerosol with a high time resolution. The total carbon content is determined by flash heating of a sample collected on a quartz-fiber filter with a time base between 20 min and 24 h. The limit of detection is approximately 0.3 µg C, which corresponds to a concentration of 0.3 µg C m−3 at a sample flow rate of 16.7 L min−1 and a 1 h sampling time base. The concentration of particulate equivalent organic carbon (OC) is determined by subtracting black carbon concentration, concurrently measured optically by an Aethalometer®, from the total carbon concentration measured by the TCA08. The combination of the TCA08 and Aethalometer (AE33) is an easy-to-deploy and low-maintenance continuous measurement technique for the high-time-resolution determination of equivalent organic and elemental carbon (EC) in different particulate matter size fractions, which avoids pyrolytic correction and the need for high-purity compressed gases. The performance of this online method relative to the standardized off-line thermo-optical OC–EC method and respective instruments was evaluated during a winter field campaign at an urban background location in Ljubljana, Slovenia. The organic-matter-to-organic-carbon ratio obtained from the comparison with an aerosol chemical speciation monitor (ACSM) was OM/OC=1.8, in the expected range.
Najdeno v: osebi
Ključne besede: total carbon, aeroosl, black carbon, carbonaceous matter
Objavljeno: 17.08.2020; Ogledov: 696; Prenosov: 24
.pdf Polno besedilo (226,45 KB)

17.
Photo-thermal interferometer
Griša Močnik, Luka Drinovec, 2020, patent

Opis: A photo-thermal interferometer for measuring the light absorption of an aerosol or gas comprises a first laser source emitting a laser beam and a beam splitter adapted to divide the laser beam into a probe beam and a reference beam. The interferometer further comprises first optical elements which are adapted to direct the probe beam such that it passes through the aerosol and interferes with the reference beam thereafter thereby causing interference patterns. A detector detects the interference patterns. The interferometer further comprises a second laser source configured to emit a pump beam for transferring energy to the aerosol. Second optical elements are adapted to direct the pump beam such that it overlaps with the probe beam at least partially in the aerosol or gas. At least one of the second optical elements modifying the pump beam is an axicon.
Najdeno v: osebi
Ključne besede: aerosol, absorption, black carbon
Objavljeno: 15.09.2020; Ogledov: 595; Prenosov: 0
.pdf Polno besedilo (482,26 KB)

18.
Performance of microAethalometers: Real-world Field Intercomparisons from Multiple Mobile Measurement Campaigns in Different Atmospheric Environments
Honey Alas, Thomas Mueller, Kay Weinhold, Sascha Pfeifer, Kristina Glojek, Asta Gregorič, Griša Močnik, Luka Drinovec, Francesca Costabile, Martina Ristorini, A. Wiedensohler, 2020, izvirni znanstveni članek

Opis: Small aethalometers are frequently used to measure equivalent black carbon (eBC) mass concentrations in the context of personal exposure and air pollution mapping through mobile measurements (MM). The most widely used is the microAethalometer (AE51). Its performance in the laboratory and field is well documented, however, there is not sufficient data in the context of its performance in different environments. In this investigation, we present the characterization of the performance of the AE51 through field unit-to-unit intercomparisons (IC), and against a reference absorption photometer from three MM campaigns conducted in drastically different environments. Five IC parameters were considered: i) study area, ii) location of IC, iii) time of day, iv) duration of IC, and v) correction for the filter-loading effect. We can conclude that it is crucial where and how long the IC have been performed in terms of the correlation between the mobile and reference instruments. Better correlations (R2 > 0.8, slope = 0.8) are achieved for IC performed in rural, and background areas for more than 10 minutes. In locations with more homogenous atmosphere, the correction of the loading effect improved the correlation between the mobile and reference instruments. In addition, a newer microAethalometer model (MA200) was characterized in the field under extreme cold conditions and correlated against another MA200 (R2 > 0.8, slope ≈ 1.0), AE51(R2 > 0.9, slope ≈ 0.9), and a stationary Aethalometer (AE33) across all wavelengths (R2 > 0.8, slope ≈ 0.7). For MA200, the loading effect was more pronounced, especially at the lower wavelengths, hence the correction of the loading effect is essential to improve the correlation against the AE33. The MA200 and AE51 proved to be robust and dependable portable instruments for MM applications. Real-world quality assurance of these instruments should be performed through field IC against reference instruments with longer durations in areas of slowly changing eBC concentration.
Najdeno v: osebi
Ključne besede: Portable instruments, Mobile monitoring, Black carbon, Instrument intercomparisons
Objavljeno: 15.09.2020; Ogledov: 542; Prenosov: 23
.pdf Polno besedilo (3,54 MB)

19.
A single-beam photothermal interferometer for in situ measurements of aerosol light absorption
Bradley Visser, Jannis Röhrbein, Peter Steigmeier, Luka Drinovec, Griša Močnik, Ernest Weingartner, 2020, izvirni znanstveni članek

Opis: We have developed a novel single-beam photothermal interferometer and present here its application for the measurement of aerosol light absorption. The use of only a single laser beam allows for a compact optical set-up and significantly easier alignment compared to standard dual-beam photothermal interferometers, making it ideal for field measurements. Due to a unique configuration of the reference interferometer arm, light absorption by aerosols can be determined directly – even in the presence of light-absorbing gases. The instrument can be calibrated directly with light-absorbing gases, such as NO2, and can be used to calibrate other light absorption instruments. The detection limits (1σ) for absorption for 10 and 60 s averaging times were determined to be 14.6 and 7.4 Mm−1, respectively, which for a mass absorption cross section of 10 m2 g−1 leads to equivalent black carbon concentration detection limits of 1460 and 740 ng m−3, respectively. The detection limit could be reduced further by improvements to the isolation of the instrument and the signal detection and processing schemes employed.
Najdeno v: osebi
Ključne besede: aerosol, aerosol absorption, black carbon, photo-thermal interferometer, climate change
Objavljeno: 29.12.2020; Ogledov: 486; Prenosov: 13
.pdf Polno besedilo (2,44 MB)

20.
Hidden black carbon air pollution in hilly rural areas - a case study of Dinaric depression
Kristina Glojek, Asta Gregorič, Griša Močnik, Andrea Cuesta-Mosquera, A. Wiedensohler, Luka Drinovec, Matej Ogrin, 2020, izvirni znanstveni članek

Opis: Air pollution is not an exclusively urban problem as wood burning is a widespread practice in rural areas. As we lack information on the air quality situation in rural mountainous regions, our aim is to examine equivalent black carbon (eBC) pollution in a typical rural karst area in the settlement of Loški Potok (Slovenia). eBC mass concentrations were measured by Aethalometer (AE-33) at two sites in Retje karst depression. The rural village station was located at the bottom of the karst depression whereas the rural background station was positioned at the top of the hill. We showthe diurnal variation of equivalent black carbon mass concentrations for different seasons. In the populated karst depression, the major source of eBC pollution are households using wood as a heating fuel reaching the highest mass concentrations in winter. Diurnal pattern of eBC from biomass burning and traffic differ due to different source activity and it is influenced by typical formation of a cold air pool from late afternoon until late morning, restricting the dispersion of local emissions. The large difference in mass concentrations between the lowest part of the village (rural station) and the top of the hill (rural background station) indicates that in a vertically stratified and stable atmosphere local sources of black carbon have a major impact onair quality conditions in the area studied. Since in Alpine and Dinaric regions there are many similar inhabited areas, we can expect similar air quality conditions also in other rural hilly areas with limited self-cleaning air capacity.
Najdeno v: osebi
Ključne besede: air pollution, black carbon, hidden geographies, diurnal variation, biomass burning, relief depressions, Loški Potok, Slovenia
Objavljeno: 04.01.2021; Ogledov: 370; Prenosov: 0
.pdf Polno besedilo (1,15 MB)

Iskanje izvedeno v 0 sek.
Na vrh