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1.
Monitoring of the particles from roads using lidar technique
Urška Koren, William Eichinger, 2009, published scientific conference contribution abstract

Published in RUNG: 07.02.2024; Views: 785; Downloads: 0

2.
Monitoring of the particles above the unpaved road by lidar technique
Urška Koren, William Eichinger, 2011, original scientific article

Abstract: Basic concepts of laser-based technique LIDAR (LIght Detection and Ranging) are discussed in this article as well as advantages and disadvantages. Presented are measurements of relative particulate concentrations above an unpaved road which were performed in a rural area near the Iowa City, Iowa, USA. The LIDAR system used in these measurements is a small, scanning LIDAR that uses elastic backscattering to obtain information on the amount of atmospheric aerosols. In the elastic LIDAR, light scattered back towards the LIDAR system from molecules and particles in the atmosphere is collected by a telescope and is detected with a photodiode. A Big Sky Laser model CFR-200 Nd:YAG laser operating at 1.064 microns is used to generate the LIDAR's outgoing signal. The laser is attached directly to the top of a 26 cm, f/10 Cassegrian telescope. A series of pulses are summed to make a single scan. A series of scans is used to build up a two- dimensional map of relative atmospheric aerosol concentrations. With a maximum range of about 6-8 km, a range resolution of 2.5 m, and a time resolution of 30 s, the LIDAR is capable of very detailed mapping of aerosols.
Keywords: LIDAR technique, particulate concentration, traffic emissions
Published in RUNG: 12.07.2023; Views: 997; Downloads: 2
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3.
Lidar Observations of Mountain Waves During Bora Episodes
Longlong Wang, Marija Bervida, Samo Stanič, Klemen Bergant, William Eichinger, Benedikt Strajnar, 2020, published scientific conference contribution

Abstract: Airflows over mountain barriers in the Alpine region may give rise to strong, gusty downslope winds, called Bora. Oscillations, caused by the flow over an orographic barrier, lead to formation of mountain waves. These waves can only rarely be observed visually and can, in general, not be reliably reproduced by numerical models. Using aerosols as tracers for airmass motion, mountain waves were experimentally observed during Bora outbreak in the Vipava valley, Slovenia, on 24-25 January 2019 by two lidar systems: a vertical scanning lidar positioned just below the peak of the lee side of the mountain range and a fixed direction lidar at valley floor, which were set up to retrieve two-dimensional structure of the airflow over the orographic barrier into the valley. Based on the lidar data, we determined the thickness of airmass layer exhibiting downslope motion, observed hydraulic jump phenomena that gave rise to mountain waves and characterized their properties.
Keywords: Bora, mountain waves, lidar observations
Published in RUNG: 08.07.2020; Views: 3038; Downloads: 0
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4.
Polarization Raman Lidar for Atmospheric Monitoring in the Vipava Valley
Longlong Wang, Samo Stanič, William Eichinger, Xiaoquan Song, Marko Zavrtanik, 2020, published scientific conference contribution

Abstract: We report on the design, construction and performance of a polarization Raman lidar, built for atmospheric monitoring in the Vipava valley in SW Slovenia, a regional air pollution hot-spot where aerosols are expected to originate from a number of different sources. Its key features are automatized remote operation capability and indoor deployment, which provide high duty cycle in all weather conditions. System optimization and performance studies include the calibration of the depolarization ratio, merging of near-range (analog) and far-range (photon-counting) data, determination of overlap functions and validation of the retrieved observables with radiosonde data.
Keywords: polarization Ramal lidar, Vipava valley, atmospheric monitoring
Published in RUNG: 08.07.2020; Views: 3271; Downloads: 0
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5.
6.
Investigation of Aerosol Properties and Structures in Two Representative Meteorological Situations over the Vipava Valley Using Polarization Raman LiDAR
Longlong Wang, Samo Stanič, William Eichinger, Griša Močnik, Luka Drinovec, Asta Gregorič, 2019, original scientific article

Abstract: Vipava valley in Slovenia is a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. Aerosol loading distributions and optical properties were investigated using a two-wavelength polarization Raman LiDAR, which provided extinction coefficient, backscatter coefficient, depolarization ratio, backscatter Ångström exponent and LiDAR ratio profiles. Two different representative meteorological situations were investigated to explore the possibility of identifying aerosol types present in the valley. In the first case, we investigated the effect of strong downslope (Bora) wind on aerosol structures and characteristics. In addition to observing Kelvin–Helmholtz instability above the valley, at the height of the adjacent mountain ridge, we found new evidence for Bora-induced processes which inject soil dust aerosols into the free troposphere up to twice the height of the planetary boundary layer (PBL). In the second case, we investigated aerosol properties and distributions in stable weather conditions. From the observed stratified vertical aerosol structure and specific optical properties of different layers we identified predominant aerosol types in these layers.
Keywords: aerosol structures, aerosol characterization, polarization Raman LiDAR, Vipava valley
Published in RUNG: 08.03.2019; Views: 4203; Downloads: 118
.pdf Full text (3,11 MB)

7.
Retrieval of Vertical Mass Concentration Distributions—Vipava Valley Case Study
Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Griša Močnik, Luka Drinovec, Janja Vaupotič, Miloš Miler, Mateja Gosar, Asta Gregorič, 2019, original scientific article

Abstract: Aerosol vertical profiles are valuable inputs for the evaluation of aerosol transport models, in order to improve the understanding of aerosol pollution ventilation processes which drive the dispersion of pollutants in mountainous regions. With the aim of providing high-accuracy vertical distributions of particle mass concentration for the study of aerosol dispersion in small-scale valleys, vertical profiles of aerosol mass concentration for aerosols from different sources (including Saharan dust and local biomass burning events) were investigated over the Vipava valley, Slovenia, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. The analysis was based on datasets taken between 1–30 April 2016. In-situ measurements of aerosol size, absorption, and mass concentration were combined with lidar remote sensing, where vertical profiles of aerosol concentration were retrieved. Aerosol samples were characterized by SEM-EDX, to obtain aerosol morphology and chemical composition. Two cases with expected dominant presence of different specific aerosol types (mineral dust and biomass-burning aerosols) show significantly different aerosol properties and distributions within the valley. In the mineral dust case, we observed a decrease of the elevated aerosol layer height and subsequent spreading of mineral dust within the valley, while in the biomass-burning case we observed the lifting of aerosols above the planetary boundary layer (PBL). All uncertainties of size and assumed optical properties, combined, amount to the total uncertainty of aerosol mass concentrations below 30% within the valley. We have also identified the most indicative in-situ parameters for identification of aerosol type.
Keywords: valley air pollution, aerosol vertical distributions, lidar remote sensing, in-situ measurements, aerosol identification
Published in RUNG: 09.01.2019; Views: 4530; Downloads: 113
.pdf Full text (7,43 MB)

8.
Aerosol monitoring over Vipava valley using Raman polarization lidar
Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Asta Gregorič, Griša Močnik, Luka Drinovec, 2018, published scientific conference contribution abstract

Abstract: Vipava valley in southwest Slovenia is a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin in mountainous terrain. An investigation of aerosol properties throughout the troposphere in different atmospheric conditions was made possible by a deployment of a two-wavelength polarization Raman lidar system combining with in-situ measurements in the valley (in the town of Ajdovščina) from September 2017. Using its aerosol identification capabilities, which are based on particle depolarization ratio and lidar ratio measurements, it was possible to identify predominant aerosol types in the observed atmospheric structures, for example in different atmospheric layers in the case of stratified atmosphere. Primary anthropogenic aerosols within the valley were found to be mainly emitted from two sources: individual domestic heating systems, which mostly use biomass fuel, and from traffic. A considerable fraction of natural aerosols (for example mineral dust and sea salt), transported over large distances, were observed both above and entering into the planetary boundary layer. According to the properties of different aerosol types, backscatter contribution of each aerosol type was evaluated and the corresponding extinction contribution was derived from lidar observations. Statistical analysis of the presence of different aerosol types was performed on the entire available dataset from 2017 and 2018.
Keywords: lidar, aerosol type, Vipava valley
Published in RUNG: 03.12.2018; Views: 4636; Downloads: 0
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9.
Vertical profiling of aerosol properties with two-wavelength polarization Raman lidar over the Vipava valley
Longlong Wang, Samo Stamoč, Asta Gregorič, Griša Močnik, Luka Drinovec, Klemen Bergant, William Eichinger, 2018, published scientific conference contribution abstract

Abstract: 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.
Keywords: Aerosol, Vipava valley, lidar
Published in RUNG: 23.04.2018; Views: 4656; Downloads: 0
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10.
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