THE EXTREMELY RAINY 2014 IN BULGARIA (original) (raw)
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Variability and trends of extreme precipitation events over Bulgaria (1961–2005)
Atmospheric Research, 2009
Heavy precipitation events often lead to river floods and flash floods causing significant loss of life and property damage, landslide activation, and other social and economic problems. The upward tendency of damages, caused by natural disasters, supports the idea that extreme events, associated with the effects of climate change, have recently occurred with greater frequency. The series of hazardous precipitation events which affected the Balkans and in particular Bulgaria in 2005 show that further study of such type of phenomena is necessary in order to improve their predictability. The subject of the present study is the variability and the trends associated with extreme precipitation events in Bulgaria during the period 1961-2005. Total precipitation amounts exceeding 30 mm/day which occur in 4 or more provinces of the country are considered to be risky for floods. We call them here heavy-rain days or events. The regime of such potentially dangerous heavy-rain/snow events is compared to those of total precipitation amounts for two periods: 1961-1990 and 1991-2005. Significant increase (more than 32%) of the days with heavy 24-hour precipitation is revealed during the second period, while the total annual rainfall is almost without changes or shows a slightly decreasing trend in many regions of the country. Besides, the contribution of heavy and torrential rain/snow to the observed annual precipitation totals increases. It is in contrast with the observed trend of decrease for the weak and moderate precipitation amounts. Two typical synoptic situations, leading to such type of extreme events in the extreme year 2005 are presented. The first is a "winter" one in February and the seconda "summer" one in July.
Recent Trends of Thunderstorms Over Bulgaria – Climatological Analysis
Ecology & Safety, 2016
Commonly the severe convective storms are not only attended by heavy rain events, but also by hail and thunderstorm activity, which on their own account cause material damages and life loses. According to Bulgarian Agency of Civil Defense and media the mean annual numbers of victims of thunders increased during the last years are about 10 people/per year The aim of the study is to present time-space variations of thunderstorm events in Bulgaria during the period 1961-2010. Visual thunderstorm observations at 42 meteorological stations with altitude below 800 m are used in a study. By the orographic and climatic features the territory of Bulgaria are divided into 6 parts and thunderstorms annual, decadal and monthly distribution and variability is presented for each of them. The comparison of two investigated periods (1961-1990, 1991-2010) show that the mean number of registered thunderstorm days increase during the second period. This growth is statistically significant only in NE Bulgaria and partially in SC Bulgaria. The 75% of all thunderstorm days is observed in warm half of the year between May and August. In the same time the significant increase of thunderstorm events in all regions from North Bulgaria during the winter months December, January and February after 1991 is established. The regime of widespread stormy fays for 10-days period during the warm half of the year (April-September) is compared for the two periods: 1961-1990 and 1991-2010. The increase in number of those hazardous events during the months from the end of the summer is received.
Hydrology
Impact on the hydrology cycle is projected to be one of the most noticeable consequences of climate change. An increase in regional dry and wet extremes has already been observed, resulting in large socioeconomic losses. The 2014 wet conditions in Bulgaria present a valuable case study for analyzing the interaction between multiple drivers that are essential for early forecasting and warning of flood events. In this paper, time series analysis of temperature, precipitation and Terrestrial Water Storage Anomaly (TWSA) is performed and cross-correlations between observations and climate variability indices are computed for a 12-year period. In Bulgaria, a positive linear temperature trend was found with precipitation and TWSA exhibiting negative trends for the period 2003–2014. The year 2014 started with a drier and warmer than usual winter followed by five consecutive wet months from March to July. We found the following long-term variations: (1) temperature showing a local minimum i...
Atmospheric Research, 2007
Over south-eastern Europe, severe weather events are often associated with Mediterranean cyclones. This paper presents a climatic study of severe storms over Bulgaria produced by synoptic-scale Mediterranean cyclones, which are the main high-impact weather systems for the region during the winter season. The study is based on a synoptically oriented data set that contains systematic information about the pronounced Mediterranean cyclones including their life and trajectories over the Mediterranean area and the severe storms over Bulgaria produced by them. The definition of a severe storm is a storm in which the wind speed and precipitation exceed thresholds of 15 m/s and 30 mm/24 h, respectively. The observed severe storms were split into two groups by the number of districts where they have caused damages. During the last years a trend of decreasing numbers of initiating synopticscale Mediterranean cyclones has been observed. However, the number of those producing a high-impact weather phenomenon over Bulgaria has increased. In these high-impact cases, the observed paths of the cyclones are connected to the specific circulation conditions over the region. In the most severe cases, almost 80% of the cyclones move through the southernmost parts of Balkan Peninsula and for a large portion of them, this motion is associated with a blocking regime in the mid-level mass field.
On Frequency Distribution and Intensity of Severe Convective Storms over Bulgaria
The subject of the present research is severe convective storms (SCS) from the Small-scale Weather Phenomena (SCSWP). Such SCSWP events are spars in space and time but cause significant property damages and losses of life with considerable impact on the economics and society in small countries. The problem concerning the climate variability and change impact on frequency, intensity and scope of SCS phenomena especially heavy rain, thunderstorms, and hail-fall, is actual and discussible. In this paper a set of severe storms over Bulgaria were selected on the basis of defined criteria for extreme values and space-dissemination of complex meteorological records for the cases of heavy rain, thunders and hail during the warm half of the year (April-September) in the period 1961-2005. The time-space variation of the thunderstorm days (as well as the ratio to hail days) was investigated. It was obtained an increase of the mean seasonal thunderstorm frequency for the period 1991-2005 versus...
About some anomalies in precipitation regime in Bulgaria
An attempt for analysis on the precipitation regime in the part of territory of Bulgaria in last 14 years is made. As a base a data published in monthly hydro-meteorological bulletins from 1995 till now are used. Some anomalies in annual trade of precipitation are revealed. Some sug-gestions about their causes are expressed.
Spatio-temporal characteristics of some convective induced extreme events in Bulgaria
2016
The fourth paper is dedicated to description and construction of the climate of cyclonic activity in the Mediterranean, proposing original and relatively simple method for calculating the potential vorticity flow. The fifth paper deals with the macrocirculation processes of the northwest Black sea region, contributing to surface wind strengthening. The sixth one gives quantitative assessment of water losses of Badovc Lake in Kosovo based on both water balance of the lake and water isotopic composition. In the seventh paper, through experimental studies within a real water management system in Bulgaria, the author proves the feasibility of the proposed methodological approach and the mathematical model, mainly for improvement and efficiency of the procedure for issuing permits for water abstractions. The eighth paper gives the latest statistical data from observations on groundwater chemical status of EU Member States in particularly Bulgaria and Belgium. The last two papers (Part on...
Thermal Science, 2015
The aim of the present research work is to bring to better understanding the recent climate change at regional scale. The tendencies of many-years variability of air temperature and precipitation in Northeastern Bulgaria are determined. In order to determine future tendencies in air temperature and precipitation variability the data from regional climate models are analyzed. The occurrence of extreme monthly temperature and precipitation totals are investigated by calculation of 10 th and 90 th percentiles of the empirical distribution in the reference period . The main result of present work is that there are a positive tendency in changes of air temperature and negative in precipitation. The regional climate model data show increasing of extreme hot and dry months which is considerable for the second part of 21 th century.