M. Chamati, P. Nenovski, M. Vellante, U. Villante, K. Schwingenschuh, M. Boudjada, V. Wesztergom – Application of DFA method to magnetic field data from SEGMA array
Abstract. We apply DFA method to magnetic field data from SEGMA array for the period August 2004 – February 2005. The SEGMA meridional array is a set of stations mainly localized in the Adriatic region (at a longitude of about 10-16° E) and devoted to magnetic field measurements in the ULF frequency range. We study the fluctuation function and the corresponding DFA scaling exponent which characterize the long-range correlations in magnetic field data series recorded by Italy and Hungary stations. For each station we consider both the similarity and the differences in the DFA index behavior. The similarity in the DFA trends is markedly associated with the global geomagnetic activity. Changes in the strength of the long-range correlations in different time scales 2-180 s and 2-900 s are reported. The disparities consist in the variable level of the DFA index value from different stations and an emergence of specific decreases of the DFA index (intervals of a lost of long-range correlations) at an individual station that last at least one day. The probable origin of such DFA index features might be related to local processes of selfsimilar characteristics either in the atmosphere/ionosphere system or in the lithosphere
D. Yu. Abramova, L. M. Abramova – Morphology of the East Europe deep structure by results of magnetic field measurements from the CHAMP satellite
Abstract. Data from the CHAMP satellite have allowed study of the constant magnetic field caused by sources in lithosphere. Interpretation of satellite anomalies maps had shown, that large-scale features such as shields, cratons and subduction zones are connected to positive anomalies (as caused enhanced magnetic susceptibility) while basins and abyssal plains are marked by negative anomalies. Authors of the present work analyse the regional lithosphere anomalies distribution revealed by results of satellite measurements above the East European craton territory and adjoining to it Alpine folded zone. Parameters of the satellite CHAMP orbit enable to receive measurements of a geomagnetic field in the practically uniform grid units above all surface of the Earth every day. It allows constructing daily average spherical harmonious model (DSHM) of the main magnetic field for each separate day. Using specified technologies of experimental data processing have been constructed maps of the anomaly magnetic field distribution at the satellite altitude for territory East European craton, the Black Sea depression and adjacent regions.
M. Syrakova, V. Mateev – Assessment of the effect of homogenization of Bulgarian temperature series
Abstract. The effect of homogenization of the seasonal and annual temperature series at 31 stations representative for the lowlands of Bulgaria, is assessed. The data cover the period 1900-2000. The homogeneity adjustments are developed by applying the Standard Normal Homogeneity Test. To assess the effect of homogenization the trends of the adjusted series are compared with the trends of the original ones and, what is more important, the trends in any particular group of stations are compared between themselves. The results show that the regional coherence of the trends of the adjusted series is much higher compared with the raw series, both in magnitude and in sign. In some cases the homogeneity corrections give rise to considerable changes in the patterns of the trends. This confirms the importance of using homogenized data in long-term climatic researches, otherwise there is a risk of obtaining false trends at some stations.
D. Yu. Abramova, L. M. Abramova – Vertical gradient electromagnetic sounding in the Aegean Sea
Abstract. This paper represents results of an electromagnetic vertical gradient sounding method (VGS) using for marine electromagnetic observations in the Aegean Sea to investigate the deep structure of the basement. Marine electromagnetic methods, in particular geomagnetic depth sounding lend to mapping the electrical conductivity structure of the seafloor. Physical properties such as porosity, partial melt content and temperature can be concluded from electrical conductivity estimates, and geological structure inferred in turn from contrasts in physical properties, including conductivity itself. In this respect, conducting layers location and temperature – depth distribution is the problem areas of high interest, as they could increase our understanding of the internal processes responsible for the characteristic features of these regions. Electrical conductivity is a parameter sensitive to fluid content in a rock and, at mantle temperatures, the degree and connectivity of partial melt. Features of the electrical conductivity in the lower crust and upper mantle can be investigated by analyzing electromagnetic variations recorded at the sea bottom and sea surface. The different models are evaluated by converting the petrology of the crust into their electrical analogs, and comparing the response of these analogs with experimental data from the Aegean Sea bottom magnetic station. Vertical gradient electromagnetic sounding in the southern part of Aegean Sea has shown presence of mantle electroconductivity anomaly, which is parallel to Aegean volcanic zone.
M. Syrakova, P. Dimitrova – Outliers in Bulgarian monthly temperature series in the period 1900-2000
Abstract. The monthly mean temperature series at 31 stations, representative for the lowlands of Bulgaria, are checked for outliers, i.e. for observations very distant from the mean value. The data cover the period 1900-2000. From November to April, negative outliers dominate, from May to October, positive outliers prevail. The total number of the outliers is greatest in July, but the outliers’ magnitudes are greater (by absolute value) in winter. The temporal distribution of the number and magnitude of the outliers over the 20th century shows, that the temperature variability in the beginning of the century can be estimated as moderate, then since 1919 till mid 1950s an increase of the number and magnitude of the outliers (both positive and negative) occurs, the period till late 1980s is relatively calm, and then a new increase of the temperature variability is in progress.
H. Chervenkov – Assessment of the acceptable concentrations of sulphur dioxide in the air over Bulgaria according to the deterioration of some technological material
Abstract. Air pollution effects on materials have been known for a long time. The original aim of the International Co-operative Programme for Materials (ICPMaterials) was to perform a quantitative evaluation of the effect of sulphur pollutants in combination with nitrogen oxides and other pollutants as well as climatic parameters on the atmospheric corrosion of important materials. The dose/response functions constitute the main results of the programme and are of outmost importance. In this study they are used to solve the reciprocal task – to find the degree of the pollution with sulphur dioxide that by fixed other parameters ensure that the rate of materials corrosion is in certain, “acceptable” limits. The calculated results are comprised with the actual pollution levels. This is as possible way to assess and map quantitatively the acceptable concentrations of sulphur dioxide in the air over Bulgaria according to the deterioration of seven wide used technological materials.
E. Botev, R. Glavcheva, B. Babachkova, S. Velichkova, I. Tzoncheva, K. Donkova, S. Dimitrova – – Preliminary data on the events recorded by NOTSSI in July – December 2004
Abstract. A map of epicenters of 692 earthquakes that occurred in the Balkan Peninsula sector outlined by latitude j =370- 470N and longitude l=190-300E is presented. Expert generalized analysis of the seismicity over the territory of Bulgaria and its adjacent lands (with more than 403 localized events) is proposed.
E. Botev, R. Glavcheva, B. Babachkova, S. Velichkova, I. Tzoncheva, K. Donkova, S. Dimitrova – Preliminary data on the events recorded by NOTSSI in January – June 2005
Abstract. A map of the epicentres of 684 earthquakes that occurred in the Balkan Peninsula sector outlined by latitude j =370- 470N and longitude l=190-300E is presented. A generalized analysis of the seismicity over the territory of Bulgaria and its adjacent lands (with 445 localized events) is proposed.
E. Botev, R. Glavcheva, B. Babachkova, S. Velichkova, I. Tzoncheva, K. Donkova, S. Dimitrova – Preliminary data on the events recorded by NOTSSI in July – December 2005
Abstract. A map of epicentres of 793 earthquakes that occurred in the Balkan Peninsula sector outlined by latitude j =370- 470N and longitude l=190-300E is presented. Expert generalized analysis of the seismicity over the territory of Bulgaria and its adjacent lands (with more than 426 localized events) is proposed.