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Natural and man-made disasters are a justified concern causing life-threats damages, affects existing budgets or disrupts national economic and social development plans. In this paper, a digital terrain model (DTM) and a geographic information system (GIS) are used to identify areas with a high risk of avalanches in the Râmeț mountain area of Alba County. Avalanches are the result of a complex interaction between terrain, weather conditions and snow cover characteristics. The most important factor among those listed is the terrain, being the only constant parameter over time. Therefore, the present study focused in particular on the determination of topographic parameters and the realization of a digital terrain model with a resolution of 0.5 m, which allows the small-scale identification of slope angle variations, which are of great interest for avalanche study. This digital terrain model was generated after processing LiDAR data obtained from a scanning campaign for the analyzed area with the Riegl LMS Q680i LiDAR system, located aboard the Hawker Beechcraft King Air C90 GTx aircraft from INCAS. The result of the analysis consisted in mapping the risk of avalanches in the Râmeț mountain area in Alba County.

The impact of anthropogenic actions on the environment and climate has recently increased the need to map the afforested areas. In this context, the three-dimensional (3D) measurement of vegetation structures plays an important role in having an efficient forest inventory and management. Nowadays, the airborne LiDAR (Light Detection And Ranging) system offers high horizontal resolution as well as vertical dimension information, making it possible to estimate both three-dimensional characteristics of individual trees and to identify the distribution of forest resources in the region. This study aims to present a processing approach for the determination of each tree’s position (X and Y location, as well as tree height) and its dimensions (crown diameter, area and volume) using geometrically accurate 3D point clouds (data sets were collected in a forested area in Argeș County, Romania). To a better understanding of the forest features and to explore the potential of remote sensing for such analysis, it was further exploited Digital Terrain Model (DTM), Digital Surface Model (DSM), and Canopy Height Model (CHM) derivation.

Clouds have an important impact on Earth’s energetic balance, so measuring accurately the microphysical parameters and using them in research has become one important step in atmospheric studies. Regarding the fact that light scattering probes convert the flow rate to concentration, any wrong assumption or measurement of the flow rate can lead to incorrect results. Applying numerical simulation to an airborne cloud microphysics measurements instrument can provide information that can be measured in any point of the sampling volume, and further used in determination of microphysics parameters, providing more accurate data. Taking this into consideration, in this paper are presented the results of numerical simulation applied to Cloud Aerosol and Precipitation Spectrometer and the comparison with results reported in literature.

The aim of this paper is to analyze different aspects of microphysical properties of mixed phase clouds, considering also the processes that are contributing to their formation. ATMOSLAB airborne laboratory, equipped with CAPS – Cloud, Aerosol and Precipitation Spectrometer sensors system was exploited to perform three flight research missions focused on cloud microphysics. For this purpose, there was analyzed the variation of 4 major parameters with high influence the cold clouds lifecycle (temperature, pressure, number concentration, effective diameter and 2D images of droplets and ice crystals) and was highlighted the occurrence of nucleation, accretion and droplet coalescence in cirrus and cirrostratus clouds.

This study is focused on finding the hypothetical conditions under of which the Romanian air space could be affected by a volcanic ash-like pollutant originating from Etna Volcano. We describe the plume transport behaviour, on its way to Romania, using the mass loading distribution displayed by the HYSPLIT (Hybrid Single Lagrangian Integrated Trajectory) model output. From the WLK (Wetterlagen-klassifikation) catalogue we have specific day sequences showing more than three days of a south-western circulation with a wet anticyclonic pattern over Romania. The resulting 24 cases in a period spanning more than a decade (2004-2014) displayed that the chances of contamination would be better for a quiescent environment around Etna’s summit. There were found ten cases in quiescent atmosphere and only four cases in windy atmosphere with Romanian air space contamination. Although it was not possible to determine the effective concentration of the fine ash pollutant it was possible to isolate the mass loading distribution in time. As the study cases displayed one order of magnitude difference between mass loading distributions it became obvious that the behaviour of the mass loading distribution in time has a directly dependence on the environmental stratification of the Etna’s summit atmosphere.

Methane (CH4) emissions to the atmosphere from the oil and gas sector in Romania remain highly uncertain despite their relevance for the European Union’s goals to reduce greenhouse gas emissions. Measurements of CH4 isotopic composition can be used for source attribution, which is important in top-down studies of emissions from extended areas. We performed isotope measurements of CH4 in atmospheric air samples collected from an aircraft (24 locations) and ground vehicles (83 locations), around oil and gas production sites in Romania, with focus on the Romanian Plain. Ethane to methane ratios were derived at 412 locations of the same fossil fuel activity clusters. The resulting isotopic signals (δ13C and δ2H in CH4) covered a wide range of values, indicating mainly thermogenic gas sources (associated with oil production) in the Romanian Plain, mostly in Prahova county (δ13C from –67.8 ± 1.2 to –22.4 ± 0.04 ‰ Vienna Pee Dee Belmnite; δ2H from –255 ± 12 to –138 ± 11 ‰ Vienna Standard Mean Ocean Water) but also the presence of some natural gas reservoirs of microbial origin in Dolj, Ialomiţa, Prahova, and likely Teleorman counties. The classification based on ethane data was generally in agreement with the one based on CH4 isotopic composition and confirmed the interpretation of the gas origin. In several cases, CH4 enhancements sampled from the aircraft could directly be linked to the underlying production clusters using wind data. The combination of δ13C and δ2H signals in these samples confirms that the oil and gas production sector is the main source of CH4 emissions in the target areas. We found that average CH4 isotopic signatures in Romania are significantly lower than commonly used values for the global fossil fuel emissions. Our results emphasize the importance of regional variations in CH4 isotopes, with implications for global inversion modeling studies.

Reducing methane emissions from the oil and gas production infrastructure is a cost-effective way for limiting global warming. In 2019, a measurement campaign in southern Romania found emission rates from the oil and gas sector substantially higher than the nationally reported emissions, with a few high-emitting sources (“super-emitters”) contributing disproportionately to total emissions. In 2021, our follow-up airborne remote sensing campaign, covering over 80 % of production sites, revealed a marked decrease in super-emitters. The observed change in the number of emitters is consistent with an emission reduction by 20 %–60 % from 2019 to 2021. This reduction is likely due to improvements in production infrastructure following the first campaign in 2019. This is further supported by additional site visits, which showed that many of the leaks identified in 2019 had indeed been mitigated. However, our top-down quantification remains higher than the bottom-up emission reports. Our study highlights the importance of measurement-based emission monitoring of climate change mitigation measures and illustrates the value of a multi-scale assessment integrating ground-based observations with large-scale airborne mapping to capture both the primary mode of emission sources and the rare, but significant, super-emitters.

Isotope measurements are increasingly used to constrain the methane (CH4) budget on various scales, from global to regional. The success of isotope-based source attribution depends to a large degree on the knowledge of the isotope signatures of the various source categories at the point of emission, but this information is in many cases lacking. Here we report the isotopic composition of CH4 emitted from 48 installations in the gas production region of Transylvania, Romania. The isotopic source signatures are quite homogeneous across the basin with average values of δ13C = (-65.6 ± 0.5 ‰) and δD = (-184 ± 1 ‰) confirming the predominantly biogenic origin of the Transylvanian gas, produced by hydrogenotrophic CO2 reduction. This is similar to values reported previously from natural seeps in Transylvania, to the natural gas exploited in the Dolj region in Southwestern Romania, and to the natural gas in the distribution grid in Cluj-Napoca. However, is more depleted in heavy isotopes than the oil-associated gas emitted in the Southern Romanian Plain, and gas leakages in the city of Bucharest. In addition, we present a step-by-step derivation of the underlying “Keeling plot” mass balance approach that is used to derive isotope source signatures.

Isotope measurements are increasingly used to constrain the methane (CH.sub.4) budget on various scales, from global to regional. The success of isotope-based source attribution depends to a large degree on the knowledge of the isotope signatures of the various source categories at the point of emission, but this information is in many cases lacking. Here we report the isotopic composition of CH.sub.4 emitted from 48 installations in the gas production region of Transylvania, Romania. The isotopic source signatures are quite homogeneous across the basin with average values of [delta].sup.13 C = (-65.6 ± 0.5 0/00) and [delta]D = (-184 ± 1 0/00) confirming the predominantly biogenic origin of the Transylvanian gas, produced by hydrogenotrophic CO.sub.2 reduction. This is similar to values reported previously from natural seeps in Transylvania, to the natural gas exploited in the Dolj region in Southwestern Romania, and to the natural gas in the distribution grid in Cluj-Napoca. However, is more depleted in heavy isotopes than the oil-associated gas emitted in the Southern Romanian Plain, and gas leakages in the city of Bucharest. In addition, we present a step-by-step derivation of the underlying \"Keeling plot\" mass balance approach that is used to derive isotope source signatures.

Isotope measurements are increasingly used to constrain the methane (CH4) budget on various scales, from global to regional. The success of isotope-based source attribution depends to a large degree on the knowledge of the isotope signatures of the various source categories at the point of emission, but this information is in many cases lacking. Here we report the isotopic composition of CH4 emitted from 48 installations in the gas production region of Transylvania, Romania. The isotopic source signatures are quite homogeneous across the basin with average values of δ13C = (−65.6 ± 0.5 ‰) and δD = (−184 ± 1 ‰) confirming the predominantly biogenic origin of the Transylvanian gas, produced by hydrogenotrophic CO2 reduction. This is similar to values reported previously from natural seeps in Transylvania, to the natural gas exploited in the Dolj region in Southwestern Romania, and to the natural gas in the distribution grid in Cluj-Napoca. However, is more depleted in heavy isotopes than the oil-associated gas emitted in the Southern Romanian Plain, and gas leakages in the city of Bucharest. In addition, we present a step-by-step derivation of the underlying “Keeling plot” mass balance approach that is used to derive isotope source signatures.