The CTA is the next generation of ground based very high energy gamma ray Imaging Atmospheric Cherenkov Telescopes. Since observations with this technique are affected by atmospheric conditions, an accurate knowledge of the atmospheric properties is fundamental to improve the precision and duty cycle of the CTA. The ARCADE Raman Lidar will be used for the on site characterization of the aerosol attenuation profiles of the UV light. This contribution includes a description of the ARCADE Lidar and the characterization of the performance of the system. The system is expected to be shipped to the northern site of the CTA (La Palma) before the end of 2017, to acquire data locally for 1 year before being moved to the southern site (Chile).
B.03 Paper at an international scientific conference
COBISS.SI-ID: 5093883One of the possibilities to investigate the influence of the scintillation on GNSS signals is using the so-called scintillation indices, S4 and sigma phi (??). They are used to estimate the fluctuations on the signal intensity and phase. This approach, which was adopted in this study, is given in the third section of this paper. The analysis was done using real Intermediate Frequency (IF) data collected by an experimental setup placed in Vietnam during a period of high solar activity. The IF data was fed into the MATLAB based software receiver capable of tracking the Galileo E1 signals after which the scintillation indices were estimated and compared with the results obtained by a professional Septentrio PolaRxS receiver.
D.06 Final report on a foreign/international project
COBISS.SI-ID: 3538683The aim of this thesis is a detailed analysis of wind and tropospheric struc- ture 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.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 4916219The aim of the dissertation was to study aerosol loading distributions and properties over the Vipava valley, an 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 Angstrom 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.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 5253883Vector field simplification aims to reduce the complexity of the flow by removing features in order of their relevance and importance, to reveal prominent behavior and obtain a compact representation for interpretation. Most existing simplification techniques based on the topological skeleton successively remove pairs of critical points connected by separatrices, using distance or area-based relevance measures. Our novel simplification algorithm is based on degree theory, has fewer boundary restrictions, and so can handle more general cases. Finally, we provide an implementation under the piecewise-linear setting and apply it to both synthetic and real-world datasets.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 27669799