Repozitorij Univerze v Novi Gorici

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

 Iskalni niz: išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida INALIIN NE išči po NaslovAvtorOpisKljučne besedePolno besediloLeto izida Vrsta gradiva: Vse vrste gradiv Habilitacijsko delo (m4) Višješolska diplomska naloga (m6) Specialistično delo (m3) Diplomsko delo * (dip) Magistrsko delo * (mag) Doktorska disertacija * (dok) Raziskovalni podatki ali korpus (data) * po starem in bolonjskem študiju Jezik: Vsi jezikiSlovenski jezikAngleški jezikNemški jezikHrvaški jezikSrbski jezikBolgarski jezikBosanski jezikČeški jezikFinski jezikFrancoski jezikItalijanski jezikJaponski jezikLitvanski jezikMadžarski jezikNemški jezik (Avstrija)Norveški jezikPoljski jezikRuski jezikSlovaški jezikSrbski jezik (cirilica)Španski jezikŠvedski jezikTurški jezikNi določenNeznan jezik Išči po: RUNG    AU - Akademija umetnosti    FAN - Fakulteta za aplikativno naravoslovje    FH - Fakulteta za humanistiko    FN - Fakulteta za naravoslovje    FPŠ - Fakulteta za podiplomski študij    FZO - Fakulteta za znanosti o okolju    PTF - Poslovno-tehniška fakulteta    UNG - Univerza v Novi Gorici    VŠU - Visoka šola za umetnost    VŠVV - Visoka šola za vinogradništvo in vinarstvoCOBISS    Univerza v Novi Gorici Opcije: Prikaži samo zadetke s polnim besedilom Ponastavi

 1 - 6 / 61 1.Study of the properties of air flow over orographic barrierMaruška Mole, 2017, doktorska disertacijaOpis: 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.Najdeno v: ključnih besedahPovzetek najdenega: ...appearance of strong north-east downslope wind in Vipava valley, called Bora. Numerical models used to...Ključne besede: remote sensing, Vipava valley, wind properties, Bora, wind gusts, wind periodicity, tropospheric structures, Kelvin-Helmholtz wavesObjavljeno: 18.09.2017; Ogledov: 2241; Prenosov: 69 Polno besedilo (45,11 MB) 2.Vertical profiling of aerosol properties with two-wavelength polarization Raman lidar over the Vipava valleyWilliam Eichinger, Klemen Bergant, Griša Močnik, Luka Drinovec, Samo Stamoč, Asta Gregorič, Longlong Wang, 2018, objavljeni povzetek znanstvenega prispevka na konferenciOpis: 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: ključnih besedahKljučne besede: Aerosol, Vipava valley, lidarObjavljeno: 23.04.2018; Ogledov: 1218; Prenosov: 0 Polno besedilo (35,82 KB) 3.STUDY OF ATMOSPHERIC AEROSOL PROPERTIES IN THE VIPAVA VALLEYLonglong Wang, doktorska disertacijaOpis: The aim of the dissertation was to study aerosol loading distributions and properties over the Vipava valley, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. An infrared Mie and a two-wavelength polarization Raman lidar systems were used as main detection tools. The polarization Raman lidar, which provides the capability to extract the extinction coefficient, backscatter coefficients, depolarization ratio, backscatter Ångström exponent, lidar ratio and water vapor mixing ratio profiles, was itself designed, built and calibrated as a part of this thesis. Lidar data, combined with in-situ measurements, was used to determine detailed information on different aerosol types. Vertical profiles of aerosol mass concentration were extracted from the Mie lidar data taken in April 2016, where the in-situ measurements of aerosol size distribution and number concentration as well as aerosol absorption coefficient and black carbon mass concentration were used to estimate the mass extinction efficiency (MEE). Aerosol morphology and chemical composition determined by SEM-EDX on sampled particles were used for the identification of primary aerosol types. Two cases with different atmospheric conditions (long range mineral dust transport and local biomass burning) and different expected the dominant presence of specific aerosol types (mineral dust and soot) were investigated in more detail. They revealed significantly different aerosol properties and distributions within the valley, affecting radiative heat exchange. A more detailed investigation of aerosol properties throughout the troposphere in different atmospheric conditions was made possible by the two-wavelength polarization Raman lidar system, deployed in Ajdovščina (town of Vipava valley) from September 2017. Using its aerosol identification capabilities, 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 the 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 traffic. Natural aerosols, transported over large distances, such as mineral dust and sea salt, were observed both above and entering into the planetary boundary layer. Backscatter contribution of each aerosol type was separated and the corresponding extinction contribution was derived from lidar observations.Najdeno v: ključnih besedahKljučne besede: Vipava valley, aerosol distribution, aerosol characterization, lidar remote sensing, in-situ measurements, aerosol loading.Objavljeno: 23.10.2018; Ogledov: 2175; Prenosov: 51 Polno besedilo (29,39 MB) 4.Aerosol monitoring over Vipava valley using Raman polarization lidarLuka Drinovec, Griša Močnik, Asta Gregorič, William Eichinger, Klemen Bergant, Samo Stanič, Longlong Wang, 2018, objavljeni povzetek znanstvenega prispevka na konferenciOpis: 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.Najdeno v: ključnih besedahKljučne besede: lidar, aerosol type, Vipava valleyObjavljeno: 03.12.2018; Ogledov: 837; Prenosov: 0 Polno besedilo (48,09 KB) 5.Investigation of Aerosol Properties and Structures in Two Representative Meteorological Situations over the Vipava Valley Using Polarization Raman LiDARLuka Drinovec, Griša Močnik, William Eichinger, Samo Stanič, Longlong Wang, Asta Gregorič, 2019, izvirni znanstveni članekOpis: 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.Najdeno v: ključnih besedahKljučne besede: aerosol structures, aerosol characterization, polarization Raman LiDAR, Vipava valleyObjavljeno: 08.03.2019; Ogledov: 705; Prenosov: 34 Polno besedilo (3,11 MB) 6.Bora wind effects on common structures in the Vipava valleyMarija Bervida, doktorska disertacijaOpis: Strong and gusty north-east wind called Bora is common in south-west regions of Slovenia, as well as along the Adriatic coast. Its intermittent behavior, related to variable strength, frequency and duration, has brought out scientific curiosity for decades. Bora affects human life and causes problems for structures built in Bora affected areas. In Slovenia, Bora is the strongest in the Vipava valley. The motivation for this research is the need to evaluate Bora wind effects on structures, commonly found in the Vipava valley region, using a high resolution computational fluid dynamics (CFD) modeling approach. To date, there are several experimental and computational constraints for accurate representation of Bora in a CFD model, therefore, the main aim of this dissertation is to build foundations for Bora wind simulations using CFD and its method of finite volumes. The dissertation incorporates the analysis of experimental measurements of Bora wind, as well as numerical modeling studies. Vertical mean wind speed profile characteristics of Bora were analyzed based on experimental measurements at Razdrto just above the Vipava valley. The obtained results contributed to the choice of Bora mean wind profiles applied at the inflow of computational models. Guidelines regarding the choice of the associated wind profile parameters were given and a new relationship between these parameters was found. As orographic barriers to the north of the Vipava valley are known to give rise to Bora and to define the specific properties of the Bora flow, numerical modeling studies were in the first place focused on the implementation of the real-scale complex terrain into a CFD model. Simulation of wind flow over orographic barrier in Vipava valley was performed using Raynolds averaged Navier-Stokes approach, providing a first estimation of the flow field over a small hill of Zemono. As resolving the turbulence characteristics of Bora is very important for the estimation of wind loads on structures, modeling studies converged towards a more appropriate approach - Large eddy simulations (LES). A crucial step in setting up an accurate LES is the generation of appropriate inflow, which was investigated for the case of atmospheric boundary layer (ABL) flow. The synthetic method PRFG$^3$ for the generation of unsteady inflow was tested and adapted as a source of an ABL flow with desired turbulence flow properties. Based on its performance, in particular on adequate reproduction of target turbulence intensities and length scales, it was found that PRFG^3 method may be used to generate velocity inflow with desired turbulence properties in LES. Finally, simulations of wind flow coming from Bora direction over the Vipava valley were performed with the aim to depict the effects of underlying orography on the flow within and above the valley. Modeling results were found to be comparable with the results of lidar based remote sensing of vertical atmospheric structures within and above the valley.Najdeno v: ključnih besedahKljučne besede: Vipava valley, Bora wind, Wind profile, Orography, Atmospheric boundary layer, Computational fluid dynamics, Numerical simulationsObjavljeno: 26.05.2020; Ogledov: 34; Prenosov: 2 Polno besedilo (35,12 MB)
Iskanje izvedeno v 0 sek.
Na vrh