11. Retrieval of Vertical Mass Concentration Distributions—Vipava Valley Case StudyLonglong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Griša Močnik, Luka Drinovec, Janja Vaupotič, Miloš Miler, Mateja Gosar, Asta Gregorič, 2019, izvirni znanstveni članek Opis: 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.
Ključne besede: valley air pollution, aerosol vertical distributions, lidar remote sensing, in-situ measurements, aerosol identification
Objavljeno v RUNG: 09.01.2019; Ogledov: 5214; Prenosov: 116
 Celotno besedilo (7,43 MB) |
12. Aerosol monitoring over Vipava valley using Raman polarization lidarLonglong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Asta Gregorič, Griša Močnik, Luka Drinovec, 2018, objavljeni povzetek znanstvenega prispevka na konferenci Opis: 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.
Ključne besede: lidar, aerosol type, Vipava valley
Objavljeno v RUNG: 03.12.2018; Ogledov: 5434; Prenosov: 0
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13. Vertical profiling of aerosol properties with two-wavelength polarization Raman lidar over the Vipava valleyLonglong Wang, Samo Stamoč, Asta Gregorič, Griša Močnik, Luka Drinovec, Klemen Bergant, William Eichinger, 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.
Ključne besede: Aerosol, Vipava valley, lidar
Objavljeno v RUNG: 23.04.2018; Ogledov: 5371; Prenosov: 0
Gradivo ima več datotek! Več... |
14. Study of the properties of air flow over orographic barrierMaruška Mole, 2017, doktorska disertacija Opis: Earth’s atmosphere is a complex system. All weather phenomena take place in its lowest layer, the troposphere, which is strongly influenced by human activities and the underlying surface orography. A good example of the influence the orography has on the behavior of air flows is the appearance of strong north-east downslope wind in Vipava valley, called Bora. Numerical models used to analyze flows in complex terrain need meteorological data both for setting the initial conditions and the verification of modeling results. Obtaining spatial distributions of meteorological observables can be challenging, especially in the case of strong winds, such as Bora, where traditional methods may be inadequate due to prohibitive wind speeds. In most cases, vertical properties of the atmosphere can be obtained using remote sensing techniques. Contrary to vertical profile measurements with traditional methods, remote sensing techniques do not require the measuring device to be placed within the flow and are therefore more appropriate for measurements in severe weather conditions such as strong winds.
The aim of this thesis is a detailed analysis of wind and tropospheric structure properties in and above the Vipava valley in a variety of typical atmospheric conditions, including strong wind events. It employs a combination of high resolution wind and lidar data in addition to standard meteorological measurements.
In Ajdovščina, there are four predominant wind directions, two of them directly connected to Bora. In the case of Bora, periodicity analysis of wind data from Ajdovščina yielded a range of possible wind gust periods between 1 and 7 minutes. The periods were not stable, with the periodogram less noisy for stable wind directions. Wavelike structures were found to be present in the troposphere in half of the investigated cases, regardless of the presence of Bora. In statically stable conditions, gravity waves propagated throughout
the planetary boundary layer (PBL). In the case of Bora, the PBL experienced oscillations with periods between 1 and 2 minutes. A shear layer was present above the PBL, causing Kelvin-Helmholtz waves at its boundaries with periods ranging from 3 to 6 minutes. In some cases, periodic structures were observed above the shear layer as well, which were found to have longer periods than those within the PBL.
Ključne besede: remote sensing, Vipava valley, wind properties, Bora, wind gusts, wind periodicity, tropospheric structures, Kelvin-Helmholtz waves
Objavljeno v RUNG: 18.09.2017; Ogledov: 7837; Prenosov: 211
Celotno besedilo (45,11 MB) |
15. Long-term investigation of aerosol variability in the boundary layer over Vipava valley based on lidar observations and black carbon measurementsLonglong Wang, Klemen Bergant, Marija Bervida, Luka Drinovec, William Eichinger, Asta Gregorič, Dafina Kikaj, Griša Močnik, Maruška Mole, Janja Vaupotič, Samo Stanič, 2017, objavljeni povzetek znanstvenega prispevka na konferenci Objavljeno v RUNG: 21.07.2017; Ogledov: 5998; Prenosov: 0
Gradivo ima več datotek! Več... |
16. Značilnosti dinamike vsebnosti vodne pare v ozračju nad Vipavsko dolino z uporabo daljinskega zaznavanja s sistemom GPS : Diplomsko deloSamo Škrlec, 2017, diplomsko delo Opis: Vsebnost vodne pare v ozračju je ena pomembnejših meteoroloških spremenljivk pri numeričnem napovedovanju vremena kot tudi dolgoročnem preučevanju podnebja. Tradicionalni načini merjenja zaradi svojih pomanjkljivosti in stroškov obratovanja ne uspejo pokriti izredno heterogene prostorske in časovne porazdelitve vodne pare v ozračju. Z vse hitrejšim razvojem Globalnih navigacijskih satelitskih sistemov (GNSS), med katere sodi tudi Globalni sistem pozicioniranja (GPS), se vedno bolj uveljavlja daljinsko zaznavanje vsebnosti vodne pare v ozračju na podlagi zakasnitev satelitskih signalov GNSS. V ta namen smo v diplomski nalogi na podlagi skoraj dvoletnih meritev GPS z dvema načrtno postavljenima stacionarnima sprejemnikoma na območju Vipavske doline po uveljavljeni metodologiji, računali skupno vsebnost vodne pare v stolpcu ozračja nad postajo GPS in v sloju ozračja znotraj Vipavske doline – od dna do roba Trnovske planote. Rezultate vsebnosti vodne pare v ozračju smo nato analizirali, primerjali in ovrednotili na podlagi izračunane absolutne vlage in drugih meteoroloških podatkov iz bližnjih merilnih postaj, opisov razvoja vremena in fotografij vremenskih razmer na območju Vipavske doline. Ugotovili smo, da lahko prisotnost padavin ter specifične nehomogene porazdelitve vlažnih zračnih mas vplivajo na razlike v absolutni vlagi, določeni na merilnih postajah in povprečni absolutni vlagi v ozračju Vipavske doline, ocenjeni s pomočjo zakasnitve signalov GNSS.
Ključne besede: daljinsko zaznavanje, meteorologija GNSS, GPS, troposferska zakasnitev, absolutna vlaga
Objavljeno v RUNG: 30.05.2017; Ogledov: 7816; Prenosov: 302
Celotno besedilo (3,50 MB) |
17. Lidar measurements of Bora wind effects on aerosol loadingMaruška Mole, Longlong Wang, Samo Stanič, Klemen Bergant, William Eichinger, Francisco Ocaña, Benedikt Strajnar, Primož Škraba, Marko Vučković, William Willis, 2017, izvirni znanstveni članek Opis: The Vipava valley in Slovenia is well known for the appearance of strong, gusty North-East Bora winds, which occur as a result of air
flows over an adjacent orographic barrier. There are three revealing wind directions within the valley which were found to give rise to
specific types of atmospheric structures. These structures were investigated using a Mie scattering lidar operating at 1064 nm, which provided high temporal and spatial resolution backscatter data on aerosols, which were used as tracers for atmospheric flows. Wind
properties were monitored at the bottom of the valley and at the rim of the barrier using two ultrasonic anemometers. Twelve time periods between February and April 2015 were selected when lidar data was available. The periods were classified according to the wind speed and direction and investigated in terms of appearance of atmospheric structures. In two periods with strong or moderate Bora, periodic atmospheric structures in the lidar data were observed at heights above the mountain barrier and are believed to be Kelvin–Helmholtz waves, induced by wind shear. No temporal correlation was found between these structures and wind gusts at the ground level. The influence of the wind on the height of the planetary boundary layer was studied as well. In periods with low wind speeds, the vertical evolution of the planetary boundary layer was found to be governed
by solar radiation and clouds. In periods with strong or moderate Bora wind, convection within the planetary boundary layer was found to be much weaker due to strong turbulence close to the ground, which inhibited mixing through the entire layer.
Ključne besede: Downslope wind
Lidar observations
Kelvin–Helmholtz waves
Bora
Objavljeno v RUNG: 06.01.2017; Ogledov: 6430; Prenosov: 0
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18. Application of the ultraviolet scanning elastic backscatter LiDAR for the investigation of aerosol variabilityFei Gao, Klemen Bergant, Samo Stanič, Longlong Wang, Ying Li, Songhui Li, Dengxin Hua, 2015, izvirni znanstveni članek Ključne besede: LIDAR, vertikalno pregledovanje, daljinsko zaznavanje, aerosoli, optične lastnosti
Objavljeno v RUNG: 17.05.2016; Ogledov: 7751; Prenosov: 39
 Povezava na celotno besedilo |
19. Observations of atmospheric structures in the Vipava valley based on Lidar dataMaruška Mole, Longlong Wang, Samo Stanič, Asta Gregorič, Klemen Bergant, William Eichinger, Marko Vučković, 2016, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: lidar, atmosferske strukture, vremenske razmere
Objavljeno v RUNG: 03.05.2016; Ogledov: 5923; Prenosov: 0
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20. Evolution of the planetary boundary layer in the presence of fog and plumeLonglong Wang, Samo Stanič, Asta Gregorič, Klemen Bergant, Maruška Mole, Marko Vučković, 2016, objavljeni povzetek znanstvenega prispevka na konferenci Ključne besede: lidar, vodna para, sipanje, GPS
Objavljeno v RUNG: 03.05.2016; Ogledov: 6497; Prenosov: 1
Gradivo ima več datotek! Več... |
