Les formes différentielles extérieures dans la géodésie II: Courbure moyenne

m m n¶rt;u mamu [7] m aa uu u aa a¶rt;u uu. uau ¶rt; u m¶rt;mu uu u u, a ¶rt;, u mu n nm. ¶rt;um a ama, ma m u¶rt; nm ¶rt; au ¶rt;amma m um. auu mamu ¶rt;um uua aa ¶rt; m unu¶rt;.     

Amplitude of a reflected wave in a horizontally stratified medium

Zusammenfassung Den Gegenstand der Arbeit bildet die Berechnung der Amplitudenkurve einer Reflexionswelle für ein bestimmtes gegebenes Medium anhand der Ersetzung dieses Mediums durch ein horizontal geschichtetes Medium mit einem einfachen Geschwindigkeitsgang in den Schichten. Die Amplitude wird nach der Nulln?herung der Strahlen-Theorie berechnet.

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Address: Ke Karlovu 3, Praha 2.     

Приветствуем вступление журнала «Studia geophysica et geodaetica» в нашу научную жизнь

председамель Ченословацкозо национальнозо зеодезическозо и зеофизическозо Комимема     

Zeitliche Konstantenveränderungen Der Gravimeter Gs 12 Nr. 129 Und Nr. 181

Zusammenfassung Es wurden die Veränderungen der Maßstabsfaktoren der Gravimeter Gs 12 Nr. 129 und Nr. 181 im Zeitabschnitt von 1964 bis 1971 untersucht. Festgestellt wurde, daß ihre Maßstabsfaktoren im Zeitabschnitt von einigen Jahren mit der Genauigkeit von 1.10^–4 als ständig betrachtet werden können.Herrn Prof. Dr. Frantiek Fiala zum 90-sten Geburtstag gewidmet     

The elastic constants of crystalline limestone computed from the velocities of body waves

m¶rt; uu nu nm u m n¶rt; , nua [4], una ¶rt; aa uma u um aumnuu. ma amuaa amu ¶rt; nm nu nm, m annuum uamuu u ¶rt;uauu ma n¶rt; . m u mu nm um ¶rt;a, nau au. ma ¶rt;a¶rt;amu nm u m n¶rt; n¶rt;um m m au.     

Un paleoplacer métamorphisé d'hématite — rutile uranifère et thorifère dans l'Atacorien (Précambrian supérieur) du Togo,Afrique occidentale

Résumé Dans l'Atacorien (Akwapimian) du Togo, qui représente probablement la partie la plus inférieure du Précambrien supérieur, on a trouvé en 1970 une minéralisation sédimentaire à hématite et rutile uranifère et thorifère. Cette minéralisation contient des minéraux radioactifs du groupe de brannérite — davidite, aussi bien que l'uranothorite et le pyrochlore. Elle a été deposée dans un paleoplacer qui fait part d'un niveau flyscheux et a été transformée sous l'action du métamorphisme régional. La minéralisation représente un nouveau type génétique des minérais titanifères en Togo, aussi bien qu'en Afrique occidentale. Cette découverte change le but de la prospection detaillée de certaines séries dédritiques du Précambrien de l'Afrique occidentale.

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In the Atacorian (Akwapimian) of Togo, which probably represents a lower part of Upper Precambrian, a sedimentary mineralization of Hematite and urano-thoriferous rutil was discovered in 1970. In this mineralization occur some radioactive minerals of the davidite-brannerite group, as well as uranothorite and pyrochlore. It is built up by paleoplacers, located in a flysch series of the Atacorien, which was exposed to a later metamorphosis. These mineralizations represent a new genetic type of titaniferious ores in Togo, as well as in West Africa. This discovery changes the scope of detailed prospection of certain detritic series of the Precambrian of West Africa.

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Institut géologique Dionýz túr.     

Flood Events of Selected European Rivers in the Sixteenth Century

The severity and frequency of sixteenth-century floods of the Rhine, the Main, the middle and upper Elbe with its tributaries, rivers of northern and central Italy, the Garonne and rivers in Catalonia and Andalusia are analyzed using documentary evidence. The basic topographical and hydrological characteristics of the rivers investigated as well as the synoptic causes of their flooding during the instrumental period are presented. Different examples of modifications of the run-off process due to anthropogenic activity are discussed. Prevalence in flood occurrence during the second half of the sixteenth century in comparison to the first half is typical for central European and Andalusian rivers (mainly in the 1560s and 1590s) and agrees with the evolution of precipitation patterns. On the other hand, Italian and Catalonian rivers, in part, had a higher occurrence of floods during the first half of the century. Changes in the flooding seasons in both halves of the century are not unambiguous. Results of an analysis on a broader European scale show floods to be a random natural phenomena with limited areal extent defined by the spatial influence of forcing meteorological factors (continuous heavy rains, sudden melting of thick snow cover, etc.). Despite some limitations of documentary evidence, series of reconstructed historical floods are valuable sources of proxy data which can be utilized for the study of the flooding fluctuations in the pre-instrumental period.     

Climate Change Projections Based on GCM-Simulated Daily Data

Three-dimensional general circulation models (GCMs) are 'state-of-the-art' tools for projecting possible changes in climate. Scenarios constructed for the Czech Republic are based on daily outputs of the ECHAM-GCM in the central European region. Essential findings, derived from validating, procedures are summarized and changes in variables between the control and perturbed experiments are examined. The resulting findings have been used in selecting the most proper methods of generating climate change projections for assessing possible hydrological and agricultural impacts of climate change in selected exposure units. The following weather variables have been studied: Daily extreme temperatures, daily mean temperature, daily sum of global solar radiation, and daily precipitation amounts. Due to some discrepancies revealed, the temperature series for changed climate conditions (2×CO ₂ ) have been created with the help of temperature differences between the control and perturbed runs, and the precipitation series have been derived from an incremental scenario based on an intercomparison of the GCMs' precipitation performance in the region. Solar radiation simulated by the ECHAM was not available and, therefore, it was generated using regression techniques relating monthly means of daily extreme temperatures and global radiation sums. The scenarios published in the paper consist of monthly means of all temperatures, their standard deviations, and monthly means of solar radiation and precipitation amounts. Daily weather series, the necessary input to impact models, are created (i) by the additive or multiplicative modification of observed weather daily series or (ii) by generating synthetic time series with the help of a weather generator whose parameters have been modified in accord with the suggested climate change scenarios.