Abstract: The most significant effects of climate change are related to temperature and precipitation. Changes in precipitation and temperature patterns affect water resource capacity, agricultural activities, global biodiversity and emergency management. In this study, using two statistical models (Mann-Kendall and Pettit’s test), climate data for the territory of Belgrade in the time interval 1961-2020 were processed. Trends were analyzed: average annual temperatures, average monthly temperatures, annual and monthly precipitation amounts. The aim of the research is to determine the statistical significance of the increasing/decreasing temperature and precipitation trends on a monthly and annual basis. Based on the obtained results, it was determined that the changing point of the annual temperature is in 1997, while a statistically significant increasing trend was observed in all months except November. The increasing trend recorded by the precipitation amount is 0.345 mm/year, but without statistical significance. The most significant results corresponding to July and October.
Abstract: The paper characterizes thermal and humidity conditions within one of the insufficiently investigated parts of Bulgaria from the climate point of view, namely the south-western slope of the Pirin Mountains. The initial data for the study (monthly temperatures and precipitation amounts) were obtained from our own meteorological monitoring station for the period 2013-2021, organized by the Department of Climatology, Hydrology and Geomorphology, Sofia University, Bulgaria. By the calculation of Mayr tetratherm (MT), monthly De Martonne aridity index (Im) and Compensated Summer Ombrothermic index (CSOi) the predominance of humid conditions in the studied area is established. There is a large inter-annual variability of the De Martonne aridity index and the Compensated Summer Ombrothermic index, which are more influenced by precipitation than air temperature in the middle part of the mountains. On the other hand, in combination with low precipitation amounts, high temperatures in recent years have contributed to the manifestation of arid features of the climate. The results of the study supplement the insufficient information about the bioclimatic characteristics of the Pirin Mountains and clarify the peculiarities of the climate in these mountains, which have two clearly distinguishable macroslopes with west-southwest and east-northeast exposure.
Abstract: The climate change on a global, regional and local scale is one of the largest problems indicated by the 21st century studies. Some of the major climate changes on the Balkan Peninsula, and in particular in Bulgaria, are related to rising temperatures and decreasing precipitation, which leads to drought and climate aridity. The present study focuses on the investigation of the climate aridity in the non-mountainous part of Southern Bulgaria in order to assess the aridity condition in temporal and spatial scale. The main investigated period is 1961-2015 and the reference periods are 1961-1990 and 1986-2015. The aridity is analysed on the basis of monthly data for air temperatures and precipitation from eight meteorological stations by calculation of De Martonne aridity index and Emberger Index. The survey shows that in all the analysed meteorological stations in Southern Bulgaria there are periods which display characteristics of the semiarid or arid climate. The aridity is well-expressed in the southwest part of Bulgaria (station Sandanski) and the western part of the Thracian lowland (station Plovdiv). Despite the aridity conditions established in the investigated region the tendencies in multiannual variability of De Martonne and Emberger indices show decreasing of aridity during the last 30 years (1986-2015) of the investigated period.
Abstract: The climate conditions may contribute significantly to the generation of several hazards in mountain areas, such landslides, wildfires, flash floods and avalanches. This study examines the variation of the main meteorological parameters with impact on avalanche triggering conditions at Bâlea-Lac Meteorological Station. At the best of our knowledge, this is the first overview of the basic climate parameters which are potentially avalanche triggers in the Făgăraș Mountains (Southern Carpathians). The study is based on data from only one weather station (Bâlea-Lac) from the period 1979-2017, assuming it is consistently relevant from climatic point of view for avalanche occurrence in the area. The results demonstrate that the theoretical circumstances for avalanche triggering (e.g. snow pack, fresh snow or wind) can be captured. This paper briefly describes the nivologic monitoring system run by the National Meteorological Administration and emphasises its utility for avalanche forecasting and alerts.