Institute of Geophysics

Institute of Geophysics 197 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Projekt "Seismologie ve školách"
Zedník, Jan ; Jedlička, Petr ; Doubravová, Jana
Projekt Seismologie ve školách si klade za úkol vývoj jednoduchého seismometru a registračního zařízení a vytvoření školní seismické sítě v České republice. Školní seismometr a další osvědčené pokusy bude možné používat na středních školách jako fyzikální pomůcku pro výuku věd o Zemi. K zařízení bude dodáván i jednoduchý zpracovatelský program a příručka pro studenty i pedagogy.
Character of precipitation during the last 200 years in Prague Klementinum and their impact on water management in the landscape
Střeštík, Jaroslav
The course of the annual precipitation displays no change over 200 years, only a very slow decline during the 20th century, particularly in its second half. The same, just a little stronger trend holds true for the number of days in each year with abundant precipitation and for percentage of annual precipitation in these days. Therefore, more and more water falls during weak rains instead of the richer ones, which is not favorable for agriculture, because more water evaporates shortly after the rain. In the same period, water flows in major rivers increase, or very little decrease, although precipitation totals are falling more rapidly. Therefore, the proportion of water flowing into the sea is increasing and the proportion remaining in the landscape decreases. All these factors contribute to an intermittent water shortages and an increasing risk of drought occurrence.
Where the centre of Bohemia, Moravia, the Czech Republic and Europe is located
Střeštík, Jaroslav
The centre of any territorial unit, as e.g. Bohemia, Czech Republic, Europe etc., is undoubtedly an attraction for the town or village where this point is located. This fact contributes surely to the significance of the locality and perhaps it attracts more visitors. This is the reason why there are more localities considered as the centre of the territorial unit. In this contribution, some most significant centres are presented. The method how to determine the centre of a selected territory as the centre of gravity is described. Using this method the positions of centres of Bohemia, Moravia, the Czech Republic and Europe have been calculated and compared with other mentioned results.
Tool for finite seismic source parameters determination - Stopping phases method, ver. 2
Kolář, Petr
A special (interactive) Tool for particular processing of seismograms from West Bohemian seismic region has been already presented (TCP2011); the purpose of the study is to determine the parameter of (simplified) seismic source model. In the present contribution we inform about code current stage, processed data and obtained results (seismic swarms from 2000 and 2008 years were investigated), as well as about particular improvements and development, namely incorporation of (i) more precise onset time determination (with use of signal over-resampling), correction of effect of (ii) anisotropy and (iii) attenuation; the graphical appearance of the Tool has been also tuned.
New interactive software for seismic data processing
Doubravová, Jana ; Horálek, Josef
Seismon is an open source software package under GNU General Public Li- cense developed by Stefan Mertl (TU Wien). It is designed as a modular pro- gram with de ned interface for speci c types of modules. This gives program- mer rules how to add new tools easily without disturbing the program integrity. Seismon is written in MATLAB and all input and output data are stored in MySQL database which can be accessed by more Seismon users simultaneously. Seismon is initially equipped with tools for communication with the database, various waveform le conversions, and basic tools for data analysis and visual- ization. To use this software for routine processing of data from local seismic network in West Bohemia (WEBNET), some adaptations had to be done, and the modi ed program was called Seismon_WB. There had to be put a great emphasis on user friendliness which required to de ne keyboard shortcuts, add status bars directly displaying current possibilities and properties, or extract the most important functions out of structured menus to main window as GUI components.
The increase of the air temperatures observed in different European localities during 1951-2010
Střeštík, Jaroslav
Uninterrupted series of annual mean temperatures from 72 European observatories have been processed. The temperature at these stations increased in general more than global temperature, but with considerable fluctuations. The increase at the individual stations is very different. It depends very slightly on the geographic longitude. Stations where lower temperature increase has been observed are located mainly at the Atlantic coast, those with higher increase being mainly in inland. There are, however, many exceptions from this rule, but the gross character of the distribution of stations with different temperature increase seems to be clear.
Prediction of solar activity in the 24th and 25th cycles
Střeštík, Jaroslav ; Mikulecký, M.
In the half of nineties we prepared a prediction of solar activity in cycles No 23 to 26. For this prediction we used the data from 1500-1995 representing 10 significant period lengths with lowest p-values. Using the superposition of these sine waves the data of 1500-1995 were excellently fitted. The prediction for 1996-2040 was constructed as an extrapolatlon of this course. We predicted that cycles No 23 and 24 wtll be longer and the value of sunspot numbers in the maximum will be lower than that in the cycle No 22. These predictions have been so far roughly fulfilled, except only the maximum of the 23rd cycle appeared in reality a little earlier. This is why the descending part of the 23rd cycle observations found itself closely under the 957o tolerance corridor of our prediction. Using now the data since 1500 till 2010 and the same prediction method we prepared anew prediction for the cycles No 24 and 25. Both cycles should be also longer, similarly as the cycle No23 in our first predlction as well as in the reality. Values of sunspot numbers in maxima should be even lower.
A completion of the catalog of polar aurorae observed in lower latitudes in 1001-1779
Střeštík, Jaroslav
In 1985 Křivský and Pejml published a catalog of polar aurorae observed in 1001-1900 in latitude lower than 55°N. In 1996 Křivský published a supplement to this catalog. This common catalog collects all data concerning the aurorae published earlier and it was in its time the most complete one. In 2004 appeared till now unknown data about polar aurorae observed in Korea in 1001-1779, These dta are, only with a few exceptions, not included in the catalog of Křivský, and vice versa. here the comprehensive catalog is presented, containing the Křivský's data s well as those from Korea. Further some regularities in the occcurrence of aurorae are presented using the comprehensive catalog. The distribution of aurorae in time agrees well with the reconstructed series of sunspot numbers and displays similar periodicities, especially the long-term ones.
The temperature and precipitation course in Prague-Karlov, 1961-2010
Střeštík, Jaroslav
The course of temperatures and precipitation in Prague over the last 50 years is presented and compared with scenarios of the further development of the climate. The temperature increased significantly and this increase is more rapid than that of the global temperature. Precipitation totals display only very small decrease over the last 50 years. However, precipitation totals in spring decreased more than the annual sums and a remarkable decrease of days with heavy rainfall takes place. These facts contribute to the observed decrease of the amount of moisture in nature and to the increased occurrence of droughts. There is no indication that all these observed trends could be different in future.
The progress of wheat prices in France and in Germany between 1531 and 1785
Střeštík, Jaroslav ; Mikulecký, M. ; Mikulecký, L.
Mean annual wheat prices in Paris and in Cologne during the 16th – 18th century display a considerable similarity, which may be expected due to the small geographical distance. In the long-term scale the prices increase, later the increase becomes slower, and this course is similar in both countries. This variation is supplemented by short-time fluctuations, again similar in both countries. In the spectra of these time series a significant peak appears in the periods near 130 and 60 years, further ones near 35 and between 14-15 years, the latter being more apparent in data from Paris. The period of solar cycle (11 years) is not significant here. Correlation with mean annual air temperatures and mean annual sunspot numbers is negative, but only a little above the limit of significance (it moves between 0.14 and 0.22). In the long-term change long-term variations of mean annual air temperatures and solar activity, valid for both countries, reflect themselves. After subtraction of the parabolic trend these correlations become lower, on the other hand, correlations with precipitation totals are more distinct. All correlations are a little higher in Germany than in France.

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