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Rainfall, with its intensity, duration, and seasonal distribution, is among the main factors causing soil erosion, which is a widespread environmental problem in Bulgaria. Rainfall erosivity shows the potential of precipitation to generate erosion processes and is an essential indicator of the climate vulnerability of a region. This paper aims to evaluate rainfall erosivity in a part of the Eastern Rhodopes Mountains, an area that is characterised by high-intensity erosion processes and high erosion risk. Local peculiarities of rainfall erosivity were revealed by the calculation of some precipitation indices based on the monthly precipitation for the period 2000–2021, such as the precipitation concentration index (PCI), Angot precipitation index, Fournier index (FI), and modified Fournier index (MFI). The analysis of the extremely wet and extremely dry months at the annual and seasonal (October–March and April–September) levels was performed to evaluate the susceptibility to erosion. The results from the study show that rainfall erosivity in the studied area varies from low to moderate in the northern part of the study area and from high to very high in the south. According to the MFI, high and very high erosivities have been observed mainly since 2012. The erosivity increases from north to south, to the area with a complex relief, where the combination of orography and atmospheric circulation make favourable conditions for the occurrence of extreme precipitation. The analyses of the calculated indices show that the precipitations in most of the studied area generally have from a low to a moderate erosivity, but this does not exclude the occurrence of cases with high and very high erosivities, which are characteristic of recent years and are related to the increase in annual precipitations and extreme precipitation months. The results of this study can contribute to the development and implementation of measures and preventive activities for the reduction and possible elimination of the negative impacts of extreme precipitation. [ABSTRACT FROM AUTHOR]

In recent decades, climate change has become a critical global issue with far-reaching consequences for regional climates and ecosystems. While regional climate models provide valuable information, there is a growing need for high-resolution simulations to assess local impacts. This paper addresses this gap by presenting the first simulation of a 3 km convection-permitting (CP) scenario simulation for Bulgaria. The main aim of this study is to assess different precipitation indices and their future changes for Bulgaria under the Representative Concentration Pathway 8.5 (RCP8.5) scenario following the Coordinated Regional Climate Downscaling Experiment Flagship Pilot Study protocol. The simulations are evaluated against high-resolution observations. We downscale Coupled Model Intercomparison Project 5 Global Climate Model (CMIP5 GCM) data for historical (1995–2004) and future (2089–2098) periods using a regional climate model (RCM) at 15 km grid spacing and parametrized convection. We use these fields as initial and boundary conditions for convection-permitting kilometer-scale simulations. The 15 km grid spacing driving model is used as a reference to assess the added value of the kilometer-scale simulation. Additionally, the 3 km seasonal mean and projected 2 m temperature and the winter snow water equivalent are presented. The results show that the kilometer-scale simulation shows better performance of wet-hour intensity in all seasons, wet-hour frequency in the spring, fall, and winter, and extreme precipitation (99.9th percentile of all precipitation events, p99.9) in the winter and fall. The kilometer-scale simulation improves the projected precipitation distribution and modifies the signal of the precipitation frequency, intensity, and heavy precipitation change over some areas. A positive projected change in the wet-hour intensity is expected in all seasons (13.86% in spring, MAM, 17.48% in summer, JJA, 1.97% in fall, SON, and 17.43% in winter, DJF) and in the heavy precipitation in the spring (13.14%) and winter (31.19%) in the kilometer-scale experiment. The projected increase in mean winter precipitation is accompanied by a significant decrease in mean winter snowfall over lowlands (50−70%). The convection-permitting Regional Climate Model, version 4.7.1 (RegCM4.7.1) suggests an increase in winter snowfall over the highest parts of the country, but a significant increase in the 2 m temperatures there. The results of this study are encouraging and may be of interest to the community of climate scientists and users of climate data for making reliable estimates of the local impacts of future climate change. [ABSTRACT FROM AUTHOR]

At present, the inventory lists of the Myriapoda of many geographical areas in Bulgaria and the comparative analyzes of the similarity between such local faunas are scarce or completely missing. The present paper presents the results of the comparative analysis of α- and β-diversity of the myriapoda communities in natural habitats in two regions in Northeastern Bulgaria – the Shumen Plateau and the Madara Plateau. The compared habitats in these plateaus have similar geographical, soil and climatic conditions, and similar species composition of plant formations. The analysis of the structure of the myriapoda communities included estimation of species diversity by determining the Shannon-Wiever index (H') and the Berger-Parker index (d). The degree of similarity between the species composition of the communities was analyzed by the Czekanowski-Dice-Sörensen, Jaccard, Bray-Curtis, Horn, Morisita-Horn indices and the corrected Chao-Sörensen and Chao-Jaccard indices. The species diversity of the millipede community in the Shumen Plateau is much greater than that of the Madara Plateau, while the diversity of the centipede communities in the two plateaus does not differ significantly. In both classes the greatest species diversity is registered in deciduous and mixed deciduous-coniferous forests. Chao-Sörensen and Chao-Jaccard indices of similarity for the myriapod communities in these habitats are the highest, approaching 1, in contrast to the other sites where the registered species composition of the centipedes is smaller and the degree of similarity is about 0.6. [ABSTRACT FROM AUTHOR]

High concentration levels of air pollutants may cause damage to plants, animals, and the health of some groups of human beings. Therefore, it is important to investigate different topics related to the high air pollution levels and to find reliable answers to the questions about the possible damages, which might take place when these levels exceed some limits. A few of the numerous questions, the answers of which are highly desirable, are listed below: (a) When are the air pollution levels dangerous? (b) What is the reason for the increased air pollution levels? (c) How can the air pollution levels be decreased? (d) Will the future climate changes result in higher and more dangerous air pollution levels? It is necessary to study carefully many issues connected with the distribution of air pollutants in a given region and with the reasons for the increases of the concentrations to high levels, which might be damaging. In order to do this, it is necessary to develop a Digital Twin of all relevant physical processes in the atmosphere and to use after that this tool in different applications. Such a tool, its name is DIGITAL AIR, has been created. Digital Twins are becoming more and more popular). Many complex problems, arising taking place in very complicated surroundings, can be handled and resolved successfully by applying Digital Twins. The preparation of such a digital tool as well as its practical implementation in the treatment of a special problem, the increase of some potentially dangerous ozone levels, will be discussed and tested in this paper. The Unified Danish Eulerian Model (UNI-DEM) is a very important part of DIGITAL AIR. This mathematical model, UNI-DEM, can be applied in many different studies related to damaging effects caused by high air pollution levels. We shall use it in this paper to get a reliable answer to a very special but extremely important question: will the future climatic changes lead to an increase in the ozone pollution levels in Bulgaria and Europe, which can potentially become dangerous for human health? [ABSTRACT FROM AUTHOR]

The question of whether the climate of Bulgaria is changing and in what direction is not yet fully understood and this gives rise to various hypotheses and analyzes, which are often a reason for heated discussions between scientists with different expertise. However, there is agreement between the scientists that the increase in the frequency and intensity of meteorological and climate extremes and the natural disasters provoked by them are related to climate change. The possible effects of climate and meteorological extreems on the risk of adverse events and natural disasters in Bulgaria have been studied by different authors for different periods of observation. There are also many open access data that we have used for analysis purposes in this paper. The article aims to interpret the results of various studies on the changes in the behavior of major climatic and meteorological elements and extremes in Bulgaria in recent decades in the context of existing scenarios and indicators of climate change in the latter. The results show that there are already changes in the indicators for the territory of our country and that Bulgaria will be significantly affected by the global warming to the end of this century. This impact will in most cases be unfavorable both for the country's economy and for the people's health and the state of ecosystems, and will contribute to increasing the risk of natural disasters. [ABSTRACT FROM AUTHOR]

The paper deals with the application of the remote sensing for drought monitoring. A way of their application in practice are shown through example for monitoring of drought that is done for three different area in Bulgaria with different pattern, for the same time (July) and for eleven randomly selected years from 1994 to 2009. For the purpose, NDVI, LAI and FPAR vegetation indexes are used. According to Intergovernmental Panel on Climate Change (IPCC) drought and floods are the most severity events threatening the country, so attention is paid on drought monitoring. [ABSTRACT FROM AUTHOR]

The paper examines songs with love and erotic content, dating back from the so-called National Revival Period. They used to be visible part of the popular culture of Bulgaria and the Southeastern Europe region in initial decades of the Modern Bulgarian statehood. These songs were originally written in Bulgarian and in Turkish, but with Cyrillic alphabet. Turkish ones are introduced for the first time in Bulgarian Literary History Studies. They were taken from books by Manol Lazarov, Petko Slaveykov, and by an unidentified author with initials K.S.M. This popular literature genre had a complex biography, following to some extent the ideological planning of the Bulgarian society and the social trajectory of the ideas of the nation, particular for that period. Initially, they were well accepted, so they gained vast popularity. Such a positive reception was particular for the period, when they were not experienced as non-matching to the emerging national ideology. Coincidingly with the rising of Bulgarian nationalism, their popularity decreased and they accumulated certain criticism, so in the beginning of the XX c. they were marginalized. In the last decades of XIX s., according to the changes of the ideological climate in Bulgaria, some of them were reinterpreted in a patriotic key. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to analyze the influence of climatic factors and their impact on the phenology of some plum varieties grown in RIMSA Troyan during the period 2019-2021. The phenophases of the beginning of flowering, the end of flowering and the period of fruit ripening were observed and analyzed. Regarding the flowering phenophase, it was found that earliest blossoming of plum cultivars occurred at the beginning of April in 2019. The blossoming period for 'Kyustendilska' both began and ended at the latest time. Every year, within 10-11 days, there was a complete overlap of the blossoming of all the studied cultivars. Regarding the fruit ripening, higher temperatures combined with low amounts of precipitation, cause an earlier onset of the ripening phase. [ABSTRACT FROM AUTHOR]

The sustainable development of enterprises is based on three pillars: economic, social, and environmental. Sustainable development aims to limit climate change and its negative impact on the natural environment. The main aim of this paper is to assess the impact of selected energy economy factors (government expenditure, environmental taxes, outlays on renewable energy sources, prices of futures contracts for CO2 emissions, outlays on R&D, and the EU Emissions Trading System (ETSEU)) on the sustainable development of the energy sectors in Bulgaria, Czechia, Estonia, and Poland, from 2008 to 2022. We use the correlation coefficients, the Ordinary Least Squares (OLS), Vector Autoregressive (VAR) Models, and the simultaneous equation. The research results indicate a variation in the direction and strength of the influence of individual economic factors in the studied countries (p < 0.05). The results can support operational and strategic decisions sustaining the sustainable development of enterprises in the analyzed countries. The results indicate the need to reform selected economic factors, with an emphasis on the increased importance of environmental taxes and the reform of the EU ETS, which is a key tool for reducing greenhouse gas emissions cost-effectively. [ABSTRACT FROM AUTHOR]

The paper discusses the impact of winter seasons climate change on crop yields in the South Central Region of Bulgaria. Twenty-two years long field observations show a progressive increase in air temperature and a decrease in snow cover in the winter seasons. The reduction of snow and the air temperature rise are supposed to lead to reduction of water availability in the spring for the winter crops and respectively to lowering their yield. By compiling observed climatic data and those obtained through a spatially distributed climatic model for the region area analysed is the relationship between these climatic parameters and the respective harvest of the winter crops for the last 5 winter seasons. The observed in the analysed period winter crops yield does not show distinctly the supposed dependence on the decrease of the snowfall amount and snow cover residence time. The yields of the last winter season 2019/2020 with the least snow cover and 2oC higher air temperature exceeded those of all other seasons. This effect is explained with the favourable combination of the high air temperature with the amount and monthly distribution of the precipitation in the season. [ABSTRACT FROM AUTHOR]

Global environmental problems and climate changes in recent decades have brought to the fore the questions related to the sustainable development of economies and the impact of these processes on the long-term returns of widely diversified portfolios. Consideration of all risk factors and potential opportunities is key to the investments of pension funds, which are called to act “in the best interest” of beneficiaries, providing secure and stable income. To unlock their potential to finance the economy’s low-carbon transition, pension funds must be convinced that the financial characteristics of green assets match the profile they are looking for and have a good understanding of their benefits and risks. The current paper aims to research the effect of including green assets in the portfolio of voluntary private pension funds in Bulgaria, applying the UPM/LPM model for portfolio optimization. The model is highly configurable to multiple constraints, operates without assumptions about the distribution of asset returns, and “captures” the various utility functions of investors. [ABSTRACT FROM AUTHOR]

The study presents a new look on the socio-ecological relations in retrospective, focusing on their formation and adaptation over time in Velingrad Municipality, Bulgaria. The dependencies between the main components of the system are outlined and the main disturbances in terms of presses and pulses are examined. Examples of trade-offs and synergies are also offered to better understand the cross-scale dynamics of the studied components. The reaction of the system to pulses in its growth phase of the adaptive cycle is reviewed. In addition, the contemporary state of the main components of the coupled human-natural system is analysed in order to identify the slow and fast variables that determine the trajectory of the system at present. The resilience thinking concept is applied in analyzing the processes within the coupled human-natural system and in identifying the mechanisms that may enhance its capacity to absorb shocks. [ABSTRACT FROM AUTHOR]

Wildfires are a common disturbance factor worldwide, especially over the last decade due to global climate change. Monitoring postfire forest regrowth provides fundamental information needed to enhance the management and support of ecosystem recovery after fires. The purpose of this study is to propose an algorithm for postfire forest regrowth monitoring using tasseled-cap-derived indices. A complex approach is used for its implementation, for which a model is developed based on three components—Disturbance Index (DI), Vector of Instantaneous Condition (VIC), and Direction Angle (DA). The final product—postfire regrowth (PFIR)—allows for a quantitative assessment of the intensity of regrowth. The proposed methodology is based on the linear orthogonal transformation of multispectral satellite images—tasseled cap transformation (TCT)—that increases the degree of identification of the three main components that change during a fire—soil, vegetation, and water/moisture—and implies a higher accuracy of the assessments. The results provide a thematic raster representing the intensity of the regrowth classes, which are defined after the PFIR threshold values are determined (HRI—high regrowth intensity; MRI—moderate regrowth intensity; and LRI—low regrowth intensity). The accuracy assessment procedure is conducted using very-high-resolution (VHR) aerial and satellite data from World View (WV) sensors, as well as multispectral Sentinel 2A images. Three different forest test sites affected by fire in Bulgaria are examined. The results show that the classified thematic raster maps are distinguished by a good performance in monitoring the regrowth dynamics, with an average overall accuracy of 62.1% for all three test sites, ranging from 73.9% to 48.4% for the individual forests. [ABSTRACT FROM AUTHOR]

Climate change as a challenge we all are facing, varying degree of economic development as a result of COVID-19, the volatility in energy prices and political as well as other factors, most countries have restructured their electricity markets in order to facilitate the use of green renewable energy. The right energy mix in a period of energy transformation is the best strategy for achieving reduction of carbon emissions. Bulgaria is a special case because it has expanded the use of solar and wind energy exponentially, without conducting an adequate preliminary forecast analysis and formulating a parallel strategy for the development and expansion of the energy storage infrastructure. In this regard, the article is focused on how the power energy market is structured with the increasingly large-scale and global penetration of renewable energy sources as primary energy sources, observing several key factors influencing the energy transition. Due to the cyclical nature of energy production and the necessity for a smooth and efficient transition, a long-term seasonal storage plan should be considered. Furthermore, solar energy production facilities have a greater share of installed power, but wind power facilities generate a roughly equivalent amount of electric energy over the course of a year. One of the aims of this research is to discover an appropriate model for predicting the electricity output of wind and solar facilities located in Bulgaria that can be used to ease the transition process. Based on thorough data analysis of energy production over the past 11 years and 5 months, our findings suggest that a SARIMA model might be appropriate, as it takes into account the seasonal cycles in the production process. [ABSTRACT FROM AUTHOR]

This study analyzes the tax relief for fuels used in agricultural production in EU member states, the Organization for Economic Co-operation and Development (OECD), and other countries. Primary attention is paid to the state aid for excise duty refund of the fuels used in agriculture in Bulgaria. Previous researches prove that fossil fuel subsidies are inefficient. According to UNDP research, for every dollar pledged to tackle the climate crisis for the world's poor, four dollars are spent on fossil fuel subsidies that keep the climate crisis alive. These circumstances require a different approach and a solid need to reform fossil fuel subsidies. The main goal of the research is to identify the possibilities for the practical application of alternative approaches for economic impact in different aspects based on research and analysis of the tax policy regarding the fuels used by agriculture. Reforming energy subsidies remains a major political challenge as societies and economies experience tensions from the Covid-19 pandemic. But the prospects for recovery after the crisis are inextricably linked to the proper alternative mechanisms, especially if subsidy reform is combined with a broader range of political and economic measures to create a more stable, secure, and sustainable agricultural sector. [ABSTRACT FROM AUTHOR]

The global climate and societal challenges in the recent years urge us to strengthen food security; thus, the rediscovery of wild foods and foraging practices is also part of the sustainability agenda. Utilization of underappreciated sources such as ruderal plants could be a valuable option, especially for vulnerable parts of the society. We present data on traditional knowledge on spring edible ruderal plant taxa preserved in rural regions of Bulgaria, combining field studies in the period 2017–2022 that were compared to the available recent and historical ethnographic and (ethno)botanical literature. Semi-structured interviews were performed with representatives of 94 households in North and South Bulgaria, focusing on collection practices, used parts, and preparation methods. We list 65 edible ruderals, belonging to 22 plant families, of which 19 appeared only in the literature sources. Unlike in the Mediterranean tradition, edible ruderal plants in Bulgaria were regarded unfavorably, as poverty food. Amaranthaceae and Asteraceae were the most represented families, with 10 taxa each. About half of the taxa were collected for their leaves or whole young herbage that is used as pastry fillings, in stewed, and in cooked dishes. Taxa used in raw salads were mostly from the literature sources. The most diverse utilization was recorded in the southern-most regions of Bulgaria, where immediate tasting of the gathered plants was reported by the participants as the way to collect food plants. The bitter ones or those with an unappealing smell were considered non-edible and were avoided. References about biologically active compounds and potential benefits were collected, classified, and discussed in regard to their potential benefits for human health. [ABSTRACT FROM AUTHOR]

This article is the first part of a wider study on the climate change aspects in Bulgaria's regulatory and policy framework for public procurement and concessions. In Part I, the authors first define, then review climate change and its potential effect on public procurement, including concessions. The present article outlines the expected climate changes in Bulgaria for the next 50 years and provides an overview of national climate change strategies and action plans that could affect procurement. As part of the analysis, we refer to relevant legal instruments at national, international and European Union (EU) levels, and consider their respective potential to accommodate the shifts in weather patterns and changes in temperatures. The Bulgarian procurement and concessions legislation is reviewed with reference to relevant EU procurement directives. Part I of the study focuses on climate change as an element of the wider category of environmental considerations, at the preparation stage of a typical whole-cycle procurement model. In the conclusion of the present article, the authors briefly outline the research agenda of the upcoming Part II. [ABSTRACT FROM AUTHOR]

Cowpea (V. unguiculata (L.) Walp) is a legume crop from Fabaceae family. Cowpea is a multipurpose crop. Green pods and leaves are used as vegetables, while several snacks and main meal dishes are prepared from the dry grain. Cowpea fixes atmospheric nitrogen through symbiosis with nodule bacteria (Bradyrhizobium spp.). During the last several years with global climatic changes with less quantity of rainfall and higher temperature cowpea represented bigger interest as for research or for farmers’ growing under dry conditions. However, cowpea is not largely known in our country. Cowpea is traditionally grown in home gardens and in small farms of southeast and southern parts of Bulgaria. The purpose of this study was to characterize 25 accessions with different geographical origin, under agro-climatic conditions of Sadovo. A total of 17 quantitative and qualitative traits were collected during vegetation and postharvest period. As a result of these study genotypes with high-yield potential, early maturity and medium to big seed size were identified. Genotypes with cat. №ВОЕ0035, A9E1073 and А8Е0553 matured for a short cycle and were considered as the earliest accessions. Plant height of studied germplasm subset ranged between 41.6 and 140 cm; number of pods per plant were from 5.2 to 20.8; weight of seeds per plant varied from 5.0g to 25.0g. The results of this research will be the base towards more efficient germplasm management in order to use cowpea collection as a source for the genetic improvement and breeding. [ABSTRACT FROM AUTHOR]

The subalpine and alpine vegetation belts are well-developed in Bulgarian mountains, and the alpine biogeographic region covers a large area in Bulgaria. Although alpine and subalpine vegetation is susceptible to climate and land-use changes, the knowledge of this vegetation in Bulgaria is very poor. The Western Stara Planina Mts. extends from Zlatishki Pass in Bulgaria in the east to Serbia, where it has its westernmost point. In its eastern part, it is composed mainly of limestone, whereas in its highest parts in the Chiprovtska Planina it is composed of acidic rocks, mainly of sandstone, conglomerate, and granite. Most of today's alpine vegetation is secondary due to long-lasting pasturing and fire management; only rock outcrops in high altitudes host primary alpine vegetation. The alpine and subalpine vegetation in the Western Stara Planina Mts. was systematically studied only on the Serbian territory; the manuscript of Vojislav Mišić which describes this vegetation was published in 1978. Here, I present vegetation classification of the Bulgarian part of the highest mountain ridge of the Western Stara Planina Mts. and fill gaps in knowledge of the alpine and subalpine vegetation in the northeastern part of the Balkan Peninsula. I recorded 78 phytosociological relevés, based on which I distinguished 12 vegetation classes, 29 associations, and nine informally described local communities. Many of these syntaxa are new to Bulgaria or are newly described according to the International Code of Phytosociological Nomenclature. A DCA ordination was conducted to display dissimilarities between relevés. Altitude, soil pH, and total cover of plants have significant influence over the sample scores. [ABSTRACT FROM AUTHOR]

The funnel web spiders (Agelenidae) are a diverse and taxonomically challenging worldwide distributed family. The genus Tegenaria Latreille, 1804, includes more than 100 valid species, mostly circumscribed to Europe and western Asia, although some species may have been subsequently introduced to other regions by anthropogenic action. Here we revise and investigate phylogenetic relationships of a group of morphologically similar species from the south-western Black Sea region and Anatolia. We remove the species Tegenaria boitanii Brignoli, 1978 stat. rev. and Tegenaria bithyniae Brignoli, 1978 from synonymy of Tegenaria percuriosa Brignoli, 1972. Tegenaria boitanii stat. rev. is restored as a valid species, re-described and re-diagnosed, and T. bithyniae syn. nov. is placed as its junior synonym. We also provide an updated diagnosis for T. percuriosa, describe a new species, Tegenaria euxinica Dimitrov sp. nov. from the mesophilic beech forests (Fagus orientalis) in Bulgaria, and review the members of T. percuriosa complex. We provide new photographs for selected species, and a map of the updated distribution ranges of all the species in the complex. The phylogenetic position and internal structure of T. percuriosa species-complex is investigated by combining available morphological and molecular (target sequencing) data with new data from the species of interest. Finally, we propose to test in future studies the hypothesis that major climatic changes during the Miocene drove diversification of the group and imprinted its biogeography. [ABSTRACT FROM AUTHOR]

This study reveals the dynamics in the number and intensity of heat waves in Bulgaria in the late 20th and early twenty-first century, as well as their impact on forest fires in the beginning of this century. Statistical methods such as linear regression and Spearman's correlation were the main tools of this study. Multiple linear regression models were used in order to reveal the complex influence of heat wave characteristics on forest fires in Bulgaria. Over the last four decades, there has been a statistically significant trend of increasing number of days belonging to heat waves. There is no significant trend (except in southwestern Bulgaria) in the average maximum temperatures of heat waves in the period 1979–2021. This is due to a change in the atmospheric circulation over Bulgaria in the twenty-first century toward increased transport of air masses from northeast in summer. The heat waves have a significant impact on the forest fires in Bulgaria in summer. In general, more, longer and having higher air temperatures heat waves provide more favorable conditions for the occurrence and development of forest fires. The results of this study can serve to build on the existing methodology for determining the risk of forest fires in the territory of Bulgaria, including factors such as the total duration and intensity of heat waves. [ABSTRACT FROM AUTHOR]

Emissions of immense amounts of desert dust into the atmosphere, spreading over vast geographical areas, are in direct feedback relation with ongoing global climate changes. An extreme large-scale Saharan dust episode occurred over Mediterranean and Europe in April 2019, driven by a dynamic blocking synoptic pattern (omega block) creating conditions for a powerful northeastward circulation of air masses rich in dust and moisture. Here, we study and characterize the effects of related dust intrusion over Sofia, Bulgaria, using lidar remote sensing combined with in situ measurements, satellite imagery, and modeling data. Optical and microphysical parameters of the desert aerosols were obtained and vertically profiled, namely, backscatter coefficients and backscatter-related Ångström exponents, as well as statistical distributions of the latter as qualitative analogs of the actual particle size distributions. Dynamical and topological features of the dust-dominated aerosol layers were determined. Height profiles of the aerosol/dust mass concentration were obtained by synergistic combining and calibrating lidar and in situ data. The comparison of the retrieved mass concentration profiles with the dust modeling ones shows a satisfactory compliance. The local meteorological conditions and the aerosol composition and structure of the troposphere above Sofia during the dust event were seriously affected by the desert air masses. [ABSTRACT FROM AUTHOR]

Two provenance tests in North-Eastern Bulgaria have been studied, whose purpose is to test the response of beech provenances from Southern Germany to the drier and warmer climatic conditions in Bulgaria, in order to predict how they would perform in a warming and drying climate. The provenance tests were established in the spring of 2010 in the area of the Varbitza and Kipilovo Forest Services with 2-year-old seedlings in a 2 x 1 m scheme in 3 replications. Four provenances of common beech were studied - 2 German (Silberbach and Ebersdorf) and 2 Bulgarian (Petrohan and Berkovitza). On the 12th year after afforestation, an inventory and measurements of the height and root collar diameter were carried out. The results were processed statistically by applying one and two-factor analysis of variance, as well as Tukey’s test for multiple comparisons. A higher survival rate was found in the provenance test in Kipilovo. The Bulgarian provenances Petrohan and Berkovitza were characterized by better growth in height in both provenance tests, and in root collar diameter - provenance Petrohan. Provenance Ebersdorf could be recommended for use in drier and warmer places in Southern Germany [ABSTRACT FROM AUTHOR]

To study climate impacts, data integration from heterogeneous sources is imperative for long-term monitoring in data sparse areas such as the High Mountain Ecosystems in the Rila Mountain, Bulgaria—difficult to both access and observe remotely due to frequent clouds. This task is especially challenging because discerning trends in vegetation location, condition and functioning requires observing over decades. To integrate the existing sparse data, we apply the Whole System framework adapted nationally in the Bulgarian Methodological Framework for Mapping and Assessment of ecosystem services. As the framework mainly relies on field data, we complement it with remote sensing vegetation indices (NDVI, NDWI and NDGI) for 42 years, together with Copernicus High Resolution Layer products and climate change reanalysis data for 40 years. We confirmed that the Whole System framework is extensible and semantically, ontologically and methodologically well suited for heterogeneous data fusion, co-analysis, reanalysis and joint interpretation. We found trends in ecosystem extent and functioning, in particular species composition, in line with climate change trends since around 1990 and exclusively attributable to climate change since 2015. Furthermore, we specified a data crosswalk between habitats and ecosystems at Level 3 (ecosystem subtype), and define new candidate indicators suitable for remotely monitoring climate change's effects on the ecosystems' extent and condition, as candidates for inclusion in the methodological framework. [ABSTRACT FROM AUTHOR]

Bulgaria, located in the Balkans, is subject to a number of natural disasters including floods, earthquakes, landslides, forest fires, strong winds, droughts, heavy snowfall and extreme temperatures. In addition to natural disasters, the country is at risk for man-made events like industrial and nuclear accidents, transport accidents, and infectious diseases. Disaster planning and prevention is a complex process that requires multiple data sources. At the same time, spatial data are often not available on-line, so the country's GIS specialists may find existing spatial data to be a great challenge. This research analyses the application of the health sector data provided by the Copernicus Climate Change Service to support the development, implementation and evaluation of disaster risk management plans in Bulgaria. The climate data visualizations provided by the service enable scientists and other stakeholders to view climate change data in a format that is simple to use, visually understandable, and usable for decision makers in government, business, and non-governmental organizations. Many of these visualizations are interdisciplinary and may be critical for gathering and applying information needed to develop disaster risk reduction plans. [ABSTRACT FROM AUTHOR]

Energy Union aims to provide clean, secure, and affordable energy for many customers leading societies towards sustainable energy development. Several criteria were introduced in this vein to evaluate the twenty-third EU countries' progress towards energy union goals. The present study proposed and applied a SWARA-TOPSIS framework based on Pythagorean fuzzy sets to rank the EU members considering their sustainable energy development progress. Ten experts working in various fields were selected to support the identified criteria, and a sensitivity analysis based on twenty scenarios was performed to evaluate the proposed model's sensitivity to weight changes. The obtained results indicated that "energy affordability" is the most influential criterion for evaluating countries, and the proposed model is sensitive to weight changes. Luxembourg is also the first-ranked country, followed by Denmark and Sweden, while Bulgaria achieved the worst rank among the EU considering its progress towards the energy union goals. The analysis of the results indicates room for improvement in implementation with the European Union goals by the EU members and the need to consider energy justice and affordability in the policy development, especially in the new members of the EU. [ABSTRACT FROM AUTHOR]

Studies of Quaternary climate change are particularly important for determining the extent and scale of the participation of natural and anthropogenic processes in global warming. For their research we applied measurements of paleoluminescent records and absolute dating of calcite flowstones from the Duhlata cave, Bosnek, Bulgaria. Using periodogram analysis of the obtained speleothem records, we established existence of new prolonged cycles of Quaternary climate change. Their intensity is comparable to that of the Milankovic cycles, which cause glaciations, so they have potential to produce similar impact on climate. [ABSTRACT FROM AUTHOR]