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Climate change and the impacts of anthropogenic activity on climate in Europe is documented in many scientific publications but the investigations about climate impact and particularly urban climate are relatively few for Bulgaria. The present paper investigates the variability of seasonal and annual air temperature in Sofia city and surrounding areas (towns Bankya and Bozhurishte) for the period 1961-2015 based on the linear regression method. In order to investigate the urban heat island (UHI) intensity, the air temperature difference between the city and its surroundings is calculated. The study shows increase of air temperature difference between the city and suburban territories during the recent years. The linkages between the observed variability of air temperature difference and atmospheric circulation and urbanization are investigated. [ABSTRACT FROM AUTHOR]

Dealing with a slowdown in economic growth is something that no country wants to be concerned with. Neither do countries want to face the reality of widening gaps in income or the realities that attend changes in the climate that we are experiencing in the world today. This study focuses on these issues and makes an attempt to find solutions to them. First there are discussed the negative impacts that climate change has on economic growth and income inequality. It is the author's contention that if a solution can be found to the various problems connected to climate change, solutions to these other problems will be found. The paper ends with a discussion of the role that business can play in finding solutions to the problems regarding climate change. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide a statistic overview of the hydrological impact of the Siriu Dam on the Buzau River (Romania), taking into account the temporal variations. Our case study uses the daily mean discharges of the Buzau River (1st of January 1955 to 31st of December 2010), registered at Nehoiu hydrometric station. The building of the Siriu Dam in 1984 required the division of the study interval into two sub-periods, each being analyzed annually and seasonally, on the series themselves or on the pre-whitened ones when prior required. The existence of a linear trend on different periods and sub-periods has been studied by using the Mann-Kendall and Seasonal MannKendall tests. In the case of the existence of a linear trend, the slopes have been calculated with Sen’s Slope Estimator. The stationarity has been studied by using the Dickey-Fuller and Kwiatkowski–Phillips–Schmidt–Shin tests. According to our preliminary results, the stationarity in trend after the dam’s construction, respectively increasing linear trends for almost all the data series and subseries was observed. The trend and stationarity outcomes proved that the Siriu Reservoir has a good impact on the homogeneity of the Buzau River’s discharge and the increasing trends are related to human activity impact coupled with climate change/variability. [ABSTRACT FROM AUTHOR]

Heat waves (HWs) represent a major danger to society and natural environment. The increasing occurrence of high magnitude and impact HWs has raised concerns worldwide and has attracted an increasing interest on this issue among climatologists over the past decade. In this review the research from 2007-2018 period on HWs definitions, driving mechanisms, present changes, future changes, and impact on human mortality is summarized. By reviewing the recent literature, it was found that whilst the atmospheric dynamic is considered to be the primary driver in HW occurrence, the sea surface temperature (SST) and land surface conditions are also essential driving components. The vastness of HW-definitions raises difficulties in selecting the appropriate methodology to identify heat episodes and to compare results from studies which used different definitions. However, by analyzing a sample of 109 papers, a preference for percentile-based definitions was observed. Therefore, 71.6% of the analyzed articles used only percentilebased definitions to identify HWs. Despite the wide variety of definitions, the analysis of changes in HWs converged to similar results. Thus, the existing recent literature provided extensive evidence of significant increase in HWs characteristics across large regions of the planet. Available scientific literature indicated that HWs have been responsible for a considerable increase in mortality in many regions of the world. In the future HWs are predicted to increase in their main characteristics leading to a greater impact on human mortality. Nevertheless, the implementation of rigorous adaptation measures can mitigate the negative impact on mortality. In conclusion, it was noted that a substantial progress has been done in the HW research, but there are still important gaps in this issue which need to be addressed. [ABSTRACT FROM AUTHOR]

In the karst areas, the epikarst system is a very sensitive environment, due to its position at the interface between soil and vadose zone. The epikarst is a weathered zone that develops as a result of both abiotic and biotic processes. In this paper we present the result of the complex investigations of epikarst zone which overlap dolines within two typical karst areas (Gömör-Torna and Tapolca) from Hungary, based on multi-criteria analysis techniques (microbiological activity assessed as biomass amount and CO2 production, seasonality of air and soil microclimate, slope orientation and exposition), in order to reveal control factors of karst processes, the territori-al and local distinctions of karst dissolution that occur in the epikarst zone. The data were compared, taking into account the human activities' impact on both sampled study areas. After four years of monitoring, the results show that there are significant season-al and diurnal variations of physical, chemical and biotic parameters of soil that cover and affect the epikarst zone. Spatial variations of these parameters were recorded as well. [ABSTRACT FROM AUTHOR]

Sustainable development has become one of the burning issues on a global, local and individual levels as a result of climate changes, pollution, rapid development and changes in the global information, economic, industrial and business sectors and value systems. In this sense, education for sustainable development, as part of lifelong learning, has become one of the most important strategic and educational policy issues in Serbia. The aim of this paper is to highlight the potential of geography as a school subject, with special reference to the role of the subject matter of geoheritage and geodiversity in education for sustainable development. The aim of pointing the benefits of integrated and out-of-classroom approaches in teaching geography, which favour an active, experiential and exploratory approach to learning about geodiversity and geoheritage, is that students can acquire competencies in sustainable development. As outcomes of geography classes, competencies also represent a basis for raising awareness and increasing accountability and responsibility in individuals for preserving geoheritage and geodiversity as part of the Serbian national treasure. [ABSTRACT FROM AUTHOR]

This paper analyses the pluviometric deficit regime during the cold semester, in the Oltenia Plain and the Southern Dobruja Plateau in the last half of the century (beginning with 1961), by treating comparatively this issue. The climatic evolutions in the last interval of time refer both to the tendency of sudden fall of atmospheric precipitations and to the tendency of air temperature increase in the last decades. The scanty precipitations registered for years on Earth extended surfaces led to phenomena of drought, which have been signalled also on the territory of our country, including in the two analysed regions. The significant differences we have found prove clearly the tendency of climate aridity in these regions situated in the two southern, south-western and namely south-eastern extremes of Romania. [ABSTRACT FROM AUTHOR]

The present paper deals with the conditions related to spring arrival in Oltenia between 2000 and 2010. A first general evaluation may be achieved by comparing the mean general indexes for the entire region of Oltenia for each spring, which are calculated as a mean of the indexes of spring arrival for all the meteorological stations from Oltenia, including the mountainous area. Out of the 11 analysed years, the lowest value was 171.1°C, registered in the spring of 2003, which followed the coldest winter (2002-2003) of the studied interval (Bogdan, Marinică, Marinică, 2010); the highest value reached 460.7°C and it was registered in the spring of 2002 that followed a warm winter, 2001-2002, the general mean of which is on the 9th place in the increasing hierarchy of the general temperature means for winter during the analysed interval. The general mean of the index for the 11 analysed years is 366.0°C with a positive percentage deviation of 43.2%, which, according to a Hellmann's type of criterion established by us, emphasizes that springs were early (E) during the entire period. The negative deviation of the latest spring (2003) was of -29.1.1%, which means a late spring (L). The second value of the index was 262.9°C, which means a normal spring. The positive deviation of this general mean of the spring arrival index for the spring in question (2003) reached 7.1%, which means a normal spring, in fact, the single normal spring of the entire interval. For Oltenia, as well as for the entire country, the decade 2000-2010 was warm. It stands out through - the warmest winters, which also registered the highest frequency, the earliest springs, the hottest summers with the more extended dog days' periods, the exceeding of certain absolute thermal maximum values in the country, some of them considered real "climatic thresholds", all induced by the climate variation limits of the end of the 20th century and the beginning of the 21st century. The predominance of early springs represent a proof of the regional climatic changes during this interval [ABSTRACT FROM AUTHOR]

Extreme weather and climate events have received increased attention in the last years due to their impact on different aspects of human activity. The aim of the present paper is to bring to better understanding of the causes of extreme precipitation occurrence in Bulgaria. An extreme precipitation month is defined as a month registering precipitation totals lower or higher than certain thresholds. Extremely wet months are defined as months with total precipitation amounts higher than 90% percentiles of the gamma distribution in the reference period 1961-1990. As extremely dry month, we consider the month with total precipitation lower than 10% of the gamma distribution. Spatial changes in the occurrence of extreme precipitation are investigated by the application of the cluster analysis. The circulation patterns were analyzed with regard to sea level pressure. The relation between the fluctuations of the extreme months and atmospheric circulation mechanism teleconnection is study by the North Atlantic Oscillation Indices (NAOI), the Eastern Atlantic pattern (EA) and the Mediterranean Oscillation Indices (MOI). [ABSTRACT FROM AUTHOR]