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... more
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.
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This paper complements the existing studies of Bora flow properties in the Vipava valley with the study of Bora turbulence in a lower region of the troposphere. The turbulence characteristics of Bora flow were derived from high resolution... more
This paper complements the existing studies of Bora flow properties in the Vipava valley with the study of Bora turbulence in a lower region of the troposphere. The turbulence characteristics of Bora flow were derived from high resolution Doppler wind lidar measurements during eight Bora wind episodes that occurred in November and December 2019. Based on the vertical profiles of wind velocity, from 80 to 180 m above the valley floor, the turbulence intensity related to all three spatial directions and the along-wind integral length scales related to three velocity components were evaluated and compared to the approximations given in international standards. The resulting turbulence characteristics of Bora flow in a deep mountain valley exhibited interesting behaviour, differing from the one expected and suggested by standards. The intensity of turbulence during Bora episodes was found to be quite strong, especially regarding the expected values for that particular category of terrai...
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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... more
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, t...
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IZVLEČEK Pri dinamiki razvoja tobakovega resarja (Thrips tabaci) imajo pomembno vlogo temperaturne razmere, ki jih v modele razvoja običajno vključujemo prek temperaturnih vsot. Ob predvidenih spremembah podnebja se bodo spremenile tudi... more
IZVLEČEK Pri dinamiki razvoja tobakovega resarja (Thrips tabaci) imajo pomembno vlogo temperaturne razmere, ki jih v modele razvoja običajno vključujemo prek temperaturnih vsot. Ob predvidenih spremembah podnebja se bodo spremenile tudi razmere za razvoj tobakovega resarja. Višje temperature zraka bodo vplivale na število rodov vrste in s tem zelo verjetno na njegovo škodljivost na gojenih rastlinah. V prispevku smo za leti 1999 in 2000 za lokaciji Ljubljana in Bilje ovrednotili uporabnost preprostega modela temperaturnih vsot za ocenjevanje števila rodov tobakovega resarja. Osnovne podatke so predstavljali rezultati monitoringa škodljivca s svetlo modrimi lepljivim i ploš čami v nasadu čebule (Allium cepa L.) na Laboratorijsk em polju Biotehniške fakultete v Ljubljani in v nasadu pora (Allium porrum L.) v Biljah. Izdelane modele smo nato uporabili za ocenjevanje sprememb v številu rodov tobakovega resarja v spremenjenih podnebnih razmerah na šestih lokacijah v Sloveniji (Ljubljana,...
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In 2001–2002, efficiency of light blue sticky boards for mass trapping of onion thrips (Thrips tabaci Lindeman) in onion crops was investigated. The aim was to reduce the damage caused by thrips on the onion leaves. The lowest percentage... more
In 2001–2002, efficiency of light blue sticky boards for mass trapping of onion thrips (Thrips tabaci Lindeman) in onion crops was investigated. The aim was to reduce the damage caused by thrips on the onion leaves. The lowest percentage of a damaged leaf surface was determined on plants, which were treated twice with deltamethrin. The sticky boards did not prove to be efficient for thrips control. In the drier year 2001, the mean yield of onion was not statistically significantly different between four treatments (insecticide, one sticky board (11.0 × 14.0 cm) per plot (1.5 m2), two sticky boards per plot and control). 2002 was more convenient for onion growing and the highest mean yield was in plants, treated with the insecticide. Though light blue sticky boards were not suitable for thrips control in onion, they were useful for monitoring.
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An NPLS regression technique was tested as an empirical downscaling method. Average monthly near-ground air tem-perature (t), specific humidity (q), and sea-level pressure (p) fields across Central and Western Europe were used as... more
An NPLS regression technique was tested as an empirical downscaling method. Average monthly near-ground air tem-perature (t), specific humidity (q), and sea-level pressure (p) fields across Central and Western Europe were used as predictors for average monthly air temperature ...
Research Interests: Mathematics, Environmental Science, Western Europe, Climate Change, Climatology, and 15 moreTime Series, Downscaling, Feature Selection, Atmospheric sciences, Uncertainty, Temperature Dependence, General Circulation Models, Precipitation, Air Temperature, Empirical Method, Extrapolation, Impact Studies, Empirical Model, dew point, and Sea Level Pressure
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Aerosol and cloud densities are the most important atmospheric parameters, which significantly influence the atmospheric conditions. The study of their spatial and temporal properties can provide detailed information about the transport... more
Aerosol and cloud densities are the most important atmospheric parameters, which significantly influence the atmospheric conditions. The study of their spatial and temporal properties can provide detailed information about the transport processes of the air masses. In recent years, lidar techniques for remote sensing of the atmospheric parameters have been greatly improved. Like the lidar systems of the Pierre Auger Observatory in Argentina (35.2S, 69.1W, 1400 m a.s.l.), the Mie lidar built at Otlica Observatory (45.93N, 13.91E, 945 m a.s.l.) in Slovenia employs the same hardware, including the transmitter, the receiver, and the DAQ system. Due to its high-power laser, large-diameter telescope, and photon-counting data-acquisition technique, the Mie lidar has the potential ability to measure the tropospheric and stratospheric atmospheric conditions, and is suitable for monitoring the changes of the cirrus clouds and atmospheric boundary layer. We have been performing routine atmosph...
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Optical properties of the atmospheric boundary layer (ABL) above the land–sea transition interface were measured using a scanning Mie lidar located 30km away from the Adriatic coast. Based on the two-dimensional range-height-indicator... more
Optical properties of the atmospheric boundary layer (ABL) above the land–sea transition interface were measured using a scanning Mie lidar located 30km away from the Adriatic coast. Based on the two-dimensional range-height-indicator scans, detailed information on the ABL was obtained, including parameters such as atmospheric optical depth, aerosol extinction coefficient and the height of the ABL. The presented case study