The theory of motion of the horizontal pendulum with a Zöllner suspension and some indications for the instrumental design     

Petr Vaníček  Geoffrey W. Lennon  Reviewer M. Schneider  Reviewer L. Skalský 《Studia Geophysica et Geodaetica》1972,16(1):30-50

Summary The aim of this paper is to examine the physical laws which govern the motion of a horizontal pendulum, mounted with the familiar Zöllner suspension geometry and to establish the equations of its motion. It is possible in this process to determine calibration parameters with greater precision and confidence and to demonstrate that procedures based upon period measurement can inherently claim a precision superior to some modern alternatives. Moreover in approaching the problem from a theoretical viewpoint it is possible to pinpoint those features of design which give rise to the troublesome aberrations. This facility makes it possible to comment upon design improvements so that a closer approach may be made to an ideal instrument.  相似文献   

On the second approximations of the deflections of the vertical and the quasigeoid height     

Petr Velkoborský 《Studia Geophysica et Geodaetica》1970,14(2):135-138

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Use of Poisson's integral in calculating higher vertical derivatives of harmonic functions — Part 1     

Petr Velkoborský  Reviewer P. Holota 《Studia Geophysica et Geodaetica》1982,26(1):3-11

Summary The higher vertical derivatives of harmonic functions, expressed by Poisson's integral, are calculated for an infinite plane. The properties of the higher derivatives of the kernel of the integral are investigated and a method of calculation is proposed, which partly eliminates the negative effect caused by their oscillation.  相似文献   

Electric and magnetic field of a stationary current in a stratified medium with a three-dimensional conductivity inhomogeneity     

Milan Hvoždara  Reviewer V. Petr 《Studia Geophysica et Geodaetica》1983,27(1):59-84

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Electromagnetic induction of a three-dimensional conductivity inhomogeneity in a two-layer earth     

Milan Hvoždara  Reviewer V. Petr 《Studia Geophysica et Geodaetica》1981,25(4):393-403

Summary The results of numerical computations of the electromagnetic field induced in a two-layer model of the Earth with a three-dimensional inhomogeneity (a block) in the subsurface layer are given. Several recommendations are given which have enabled the solution of a complicated system of integral equations and the computation of the field at the Earth's surface in an effective way. The analysis of the obtained solution has proved that, in an anomalous electromagnetic field, the field of the horizontal electric dipole, oriented in the direction of the exciting field, is predominant. A number of practically usable diagrams and approximative formulae is given.  相似文献   

The second most disastrous windstorm of the nineteenth century in the Czech Lands, 26-27 October 1870     

Brázdil  Rudolf  Stucki  Peter  Szabó  Péter  Dobrovolný  Petr  Řezníčková  Ladislava  Kotyza  Oldřich  Valášek  Hubert  Dolák  Lukáš  Zahradníček  Pavel  Suchánková  Silvie 《Theoretical and Applied Climatology》2018,132(3-4):1201-1216

Theoretical and Applied Climatology - One of the most disastrous windstorms to take place over the Czech Lands occurred on the night of 26/27 October 1870. It is here analysed through the use of...  相似文献   

Geochemical heterogeneity and isotope geochemistry of natural attenuation processes in a gasoline-contaminated aquifer at the Hnevice site,Czech Republic     

Barbora Topinkova  Kamil Nesetril  Josef Datel  Ondrej Nol  Petr Hosl 《Hydrogeology Journal》2007,15(5):961-976

The geochemical processes, water–rock interactions and stable isotopes distribution (δ¹³C of DIC and δ¹⁸O and δ³⁴S of \({\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} \)) were investigated in the gasoline-contaminated aquifer at the Hnevice site, 50  km northwest of Prague, Czech Republic. Diesel, gasoline and oil leaks originate from a large fuel storage area causing heavy contamination of the saturated and unsaturated zones in an area of about 0.7  km². Groundwater investigations were conducted using five multilevel sampler wells with emphasis on redox parameters and degradation by-products and a solid-phase study focused on iron speciation and determination of principal and secondary minerals. Based on the study of groundwater and solid-phase geochemistry, four different geochemical zones were described. Zone I is thought to be background consisting of an aerobic aquifer and the absence of reduced species in significant concentrations. Zone II is situated in the plume core with methanogenic, sulphate and iron-reducing conditions accompanied by ankerite and kutnahorite precipitates and significant depletion of the oxidation capacity of the aquifer. Zone III is a mixing (corona) zone, situated at the fringe of the plume with high biodegradation rates and Fe(III)-precipitants. In zone IV, reoxidation of Fe(II) minerals (with e.g. the occurrence of psilomelane and cornelite) is typical.  相似文献   

A spatial and temporal drought risk assessment of three major tree species in Britain using probabilistic climate change projections     

Michal Petr  Luc G. J. Boerboom  Anne van der Veen  Duncan Ray 《Climatic change》2014,124(4):791-803

Probabilistic climate data have become available for the first time through the UK Climate Projections 2009, so that the risk of change in tree growth can be quantified. We assessed the drought risk spatially and temporally using drought probabilities calculated from the weather generator data and tree species vulnerabilities using Ecological Site Classification model across Britain. We evaluated the drought impact on the potential yield class of three major tree species (Picea sitchensis, Pinus sylvestris, and Quercus robur), which cover around 59 % (400,700 ha) of state-managed forests, across the lowlands and uplands. We show that drought impacts result mostly in reduced tree growth over the next 80 years when using B1, A1B, and A1FI IPCC emissions scenarios, but varied spatially. We found a maximum reduction of 94 % but also a maximum increase of 56 % in potential stand yield class in the 2080s from the baseline climate (1961–1990). Furthermore, potential production over the state-managed forests for all three species in the 2080s is estimated to decrease due to drought by 42 % in the lowlands and by 32 % in the uplands in comparison to the baseline climate. Our results reveal that potential tree growth and forest production on the state-managed forests in Britain is likely to reduce, and indicate where and when adaptation measures are required. Moreover, this paper demonstrates the value of probabilistic climate projections for an important economic and environmental sector.  相似文献   

Long-term variability of temperature and precipitation in the Czech Lands: an attribution analysis     

Jiří Mikšovský  Rudolf Brázdil  Petr Štĕpánek  Pavel Zahradníček  Petr Pišoft 《Climatic change》2014,125(2):253-264

Among the key problems associated with the study of climate variability and its evolution are identification of the factors responsible for observed changes and quantification of their effects. Here, correlation and regression analysis are employed to detect the imprints of selected natural forcings (solar and volcanic activity) and anthropogenic influences (amounts of greenhouse gases—GHGs—and atmospheric aerosols), as well as prominent climatic oscillations (Southern Oscillation—SO, North Atlantic Oscillation—NAO, Atlantic Multidecadal Oscillation—AMO) in the Czech annual and monthly temperature and precipitation series for the 1866–2010 period. We show that the long-term evolution of Czech temperature change is dominated by the influence of an increasing concentration of anthropogenic GHGs (explaining most of the observed warming), combined with substantially lower, and generally statistically insignificant, contributions from the sulphate aerosols (mild cooling) and variations in solar activity (mild warming), but with no distinct imprint from major volcanic eruptions. A significant portion of the observed short-term temperature variability can be linked to the influence of NAO. The contributions from SO and AMO are substantially weaker in magnitude. Aside from NAO, no major influence from the explanatory variables was found in the precipitation series. Nonlinear forms of regression were used to test for nonlinear interactions between the predictors and temperature/precipitation; the nonlinearities disclosed were, however, very weak, or not detectable at all. In addition to the outcomes of the attribution analysis for the Czech series, results for European and global land temperatures are also shown and discussed.  相似文献   

The year-long unprecedented European heat and drought of 1540 – a worst case     

Oliver Wetter  Christian Pfister  Johannes P. Werner  Eduardo Zorita  Sebastian Wagner  Sonia I. Seneviratne  Jürgen Herget  Uwe Grünewald  Jürg Luterbacher  Maria-Joao Alcoforado  Mariano Barriendos  Ursula Bieber  Rudolf Brázdil  Karl H. Burmeister  Chantal Camenisch  Antonio Contino  Petr Dobrovolný  Rüdiger Glaser  Iso Himmelsbach  Andrea Kiss  Oldřich Kotyza  Thomas Labbé  Danuta Limanówka  Laurent Litzenburger  Øyvind Nordl  Kathleen Pribyl  Dag Retsö  Dirk Riemann  Christian Rohr  Werner Siegfried  Johan Söderberg  Jean-Laurent Spring 《Climatic change》2014,125(3-4):349-363

The heat waves of 2003 in Western Europe and 2010 in Russia, commonly labelled as rare climatic anomalies outside of previous experience, are often taken as harbingers of more frequent extremes in the global warming-influenced future. However, a recent reconstruction of spring–summer temperatures for WE resulted in the likelihood of significantly higher temperatures in 1540. In order to check the plausibility of this result we investigated the severity of the 1540 drought by putting forward the argument of the known soil desiccation-temperature feedback. Based on more than 300 first-hand documentary weather report sources originating from an area of 2 to 3 million km², we show that Europe was affected by an unprecedented 11-month-long Megadrought. The estimated number of precipitation days and precipitation amount for Central and Western Europe in 1540 is significantly lower than the 100-year minima of the instrumental measurement period for spring, summer and autumn. This result is supported by independent documentary evidence about extremely low river flows and Europe-wide wild-, forest- and settlement fires. We found that an event of this severity cannot be simulated by state-of-the-art climate models.  相似文献