Some characteristics of quasi-biennial geomagnetic oscillations of solar origin     

Emil M. Apostolov  Vojtěch Letfus  Reviewer J. Laštovička 《Studia Geophysica et Geodaetica》1988,32(2):171-186

Summary The monthly means of the geomagnetic index aa and of the relative sunspot numbers were used to analyse the quasi-biennial oscillations (QBO) in geomagnetic activity related to an analogous variation in solar activity. Statistical methods of time series analysis were applied: autocorrelation and power spectrum, cross-correlation, complex demodulation, and the digital filter technique. The aim of this investigation was not only the detection of QBO in geomagnetic activity, which has been done by various authors, but also the determination of the time variation of the period, phase and amplitude of these oscillations in the given time interval with reference to the results of Apostolov [2] and Apostolov and Letfus [4]. The following main results have been obtained: The characteristic period of QBO in geomagnetic activity is shorter and varies in a narrower interval than that in sunspot activity; the lifetime of the oscillations is about 22 years and roughly coincides with Hale's cycle; the amplitude of QBO in geomagnetic activity has its maximum on the decreasing branch of the sunspot cycle; the QBO in geomagnetic activity follows the analogous variation in sunspot activity with a delay of 2 to 6 months for various solar cycles, as compared with the 3 to 22 moths for the raw, unfiltered data. The causes of the differences in the characteristics of QBO in geomagnetic and sunspot activity are considered and it is shown that these differences do not contradict the solar control of this phenomenon.

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¶rt;uaum u¶rt;a aa u mum ua nm unau ¶rt; aaua au¶rt;mu uu () aumo amumu, a mmmuu auauu amumu. nau ¶rt;u mamumuu m¶rt; aaua ¶rt;: nm mu, amau u u aau, na ¶rt;¶rt;u, ua umau. m u¶rt;au m ¶rt;u uaum amumu, m ¶rt;a au amau, m m n¶rt;u auau nu¶rt;a, a u anum¶rt; mu uu ¶rt; ¶rt;a umaa u, uma mam nma [2] u nma u ma [4]. u n ¶rt;u mam: aamumuu nu¶rt; aum amumu u um uma amumu nm; uu uu nuuum a 22¶rt;a u a u a; anum¶rt;a aum amumu ¶rt;muam aua uu a na¶rt;a mu ua nm; aum amumu ¶rt;m aau auau amumu nm n¶rt;au 2 n 6 a ¶rt; a u n au n¶rt;au 3 n 22 a ¶rt; umua naa ¶rt;a. ¶rt;am nuu auu aamumu aum u amum u naa, m mu auu nmum m m u.

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IGU Working Group on “Landscape synthesis” Geoecological foundation of complex landscape management     

Emil Mazúr  Ián Drdoŝ 《GeoJournal》1981,5(2):192-196

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Sunrise effect on atmospherics and its relation to the direction of the night noise source     

Vojtěch Letfus  Emil M. Apostolov  Jan Klimeš  Reviewer J. Laštovička 《Studia Geophysica et Geodaetica》1982,26(3):281-294

a auauu m ma ¶rt;a a a amua aama m¶rt;, m n¶rt;m anau umu, u m nu¶rt;um ¶rt;a a nu mau am . m¶rt; nu a¶rt;u amu a ¶rt; mau aauu nu (nu, au, 27 , u uma, au, 29 ) mu 1967–1970 . m¶rt; n¶rt;mam ¶rt;a u, u aaua mam, m n¶rt;nmu a¶rt; m¶rt;am anau umua u am, u m umuu a m mnua. ¶rt;u u mam aaua m ma nuau ¶rt;u n u ma ¶rt;a a. anau um a u mau mu¶rt;a ¶rt; u u -ana¶rt;u anauu. au ¶rt;a u n¶rt;¶rt;uam aau m ¶rt;a u a¶rt;a a a amua a¶rt; n [15]. m, m mu¶rt;a um m m aa m anmauu ¶rt;u a¶rt;u, m a auum u ¶rt; anmau a¶rt;u u mau ¶rt;m (uu m m u), u ma m um a¶rt; m auauu anauu amu nu¶rt;u a¶rt;am ¶rt; ¶rt;a a.  相似文献   

Crystal structures of iron bearing tetrahedrite and tennantite at 25 and 250°C by means of Rietveld refinement of synchrotron data     

Karen Friese  Andrzej Grzechnik  Emil Makovicky  Tonči Balić-Žunić  Sven Karup-Møller 《Physics and Chemistry of Minerals》2008,35(8):455-465

Rietveld refinement of X-ray synchrotron data was performed for two synthetic tetrahedrite samples, with 0.61 and 1.83 Fe atoms, and two synthetic tennantite samples with 0.10 and 1.23 Fe atoms p.f.u. M₁₂(Sb,As)₄S₁₃. Measurements were performed at 25 and 250°C. For both the phases, increased Fe substitution is reflected in the increased tetrahedral ‘Cu1’–S distance (‘Cu1’ is a site of Fe substitution) and Cu2–S distances. Cu2 was refined as a split position; the Cu2–Cu2 split about the plane of the S1₂S2 triangle is about 0.56 and 0.65 Å for tetrahedrite and tennantite, respectively. Cu2–Cu2 distances in the structure cavity are 2.8–2.9 Å. Between 25 and 250°C, the lattice parameter a increased by 0.02–0.04 Å and the interatomic distances by 0.01 Å on an average. Thermal expansion coefficients of little-substituted samples are similar to those of unsubstituted samples, whereas thermal expansion appears to decrease with increasing substitution by Fe. The Cu2–Cu2 split increases at 250°C by about 0.1 Å for tetrahedrite and by more than 0.15 Å for tennantite but the cage expansion is minimal so that the Cu2–Cu2 distances in the cavity decrease with temperature. Difference Fourier maps indicate that there is little residual electron density left between the two Cu2 half-sites in tetrahedrite but this inter-site density is substantially higher in tennantite. It increases with temperature, especially in the little-substituted tennantite sample.  相似文献   

MODIS-NDVI-based mapping of the length of the growing season in northern Fennoscandia     

Stein Rune Karlsen  Anne Tolvanen  Eero Kubin  Jarmo Poikolainen  Kjell Arild Høgda  Bernt Johansen  Fiona S. Danks  Paul Aspholm  Frans Emil Wielgolaski  Olga Makarova 《International Journal of Applied Earth Observation and Geoinformation》2008

Northern Fennoscandia is an ecologically heterogeneous region in the arctic/alpine-boreal transition area. Phenology data on birch from 13 stations and 16-day MODIS-NDVI composite satellite data with 250 m resolution for the period 2000 to 2006 were used to map the growing season. A new combined pixel-specific NDVI threshold and decision rule-based mapping method was developed to determine the onset and end of the growing season. A moderately high correlation was found between NDVI data and birch phenology data. The earliest onset of the growing season is found in the narrow strip of lowland between the mountains and the sea along the coast of northern Norway. The onset follows a clear gradient from lowland to mountain corresponding to the decreasing temperature gradient. In autumn, the yellowing of the vegetation shows a more heterogeneous pattern. The length of the growing season is between 100 and 130 days in 55% of the study area.  相似文献   

Modeling atmospheric chemistry and transport with dynamic adaptive resolution     

Emil M. Constantinescu  Adrian Sandu  Gregory R. Carmichael 《Computational Geosciences》2008,12(2):133-151

We discuss an adaptive resolution system for modeling regional air pollution based on the chemical transport model STEM. The grid adaptivity is implemented using the generic adaptive mesh refinement tool Paramesh, which enables the grid management operations while harnessing the power of parallel computers. The computational algorithm is based on a decomposition of the domain, with the solution in different subdomains being computed with different spatial resolutions. Various refinement criteria that adaptively control the fine grid placement are analyzed to maximize the solution accuracy while maintaining an acceptable computational cost. Numerical experiments in a large-scale parallel setting (~0.5 billion variables) confirm that adaptive resolution, based on a well-chosen refinement criterion, leads to the decrease in spatial error with an acceptable increase in computational time. Fully dynamic grid adaptivity for air quality models is relatively new. We extend previous work on chemical and transport modeling by using dynamically adaptive grid resolution. Advantages and shortcomings of the present approach are also discussed.  相似文献   

Planetary Boundary-Layer Modelling and Tall Building Design     

Emil Simiu  Liang Shi  DongHun Yeo 《Boundary-Layer Meteorology》2016,159(1):173-181

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Physikalisch-chemische Untersuchungen im Staubecken Augst-Wyhlen     

Emil Riggenbach Dr.phil. 《Aquatic Sciences - Research Across Boundaries》1924,3(1-2):87-116

Ohne Zusammenfassung  相似文献   

Ventilation of the Black Sea pycnocline. Parameterization of convection, numerical simulations and validations against observed chlorofluorocarbon data   总被引：1，自引：0，他引：1  

E.V. Stanev  J. Staneva  J.L. Bullister  J.W. Murray 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):2137-2169

Data from field observations and numerical model simulations are used to understand and quantify the pathways by which passive tracers penetrate into the Black Sea intermediate and deep layers. Chlorofluorocarbon (CFC) concentrations measured during the1988 R.V. Knorr cruise show strong decrease with increasing density in the Black Sea and illustrate the very slow rate of ventilation of deep water in this basin. We develop a 3D numerical model based on the Modular Ocean Model (MOM), and calibrate it in a way to produce consistent simulations of observed temperature, salinity and CFCs. One important feature is the implementation of a special parameterization for convection, which is an alternative of the convective adjustment in MOM and handles the penetration of the Bosporus plume into the halocline. The model forcing includes interannually variable wind, heat and water fluxes constructed from Comprehensive Ocean–Atmosphere Data Set and ECMWF atmospheric analysis data and river runoff data. The analysis of observations and simulated data are focused on correlations between thermohaline and tracer fields, dynamic control of ventilation, and the relative contributions of sources at the sea surface and outflow from the Bosporus Strait in the formation of intermediate and deep waters. A simple theory is developed which incorporates the outflow from the strait along with the vertical circulation (vertical turbulent mixing and Ekman upwelling) and reveals their mutual adjustment. The analyses of simulated and observed CFCs demonstrate that most of the CFC penetrating the deep layers has its source at the sea surface within the Black Sea rather than from the Marmara Sea via the Bosporus undercurrent. Under present-day conditions, the surface CFC signals have reached only the upper halocline. Intrusions below 600 m are not simulated. The major pathways of penetration of CFCs are associated with cold-water mass formation sites, Bosporus effluent, as well as with the diapycnal mixing in the area of Rim Current. Future CFC sampling strategies coherent with the unique conditions in the Black Sea are discussed.  相似文献   

Über Miktitbildung     

Prof. Dr. Emil Lehmann 《Contributions to Mineralogy and Petrology》1952,3(1):9-35

Ohne ZusammenfassungHerrn Professor Dr.O. H. Erdmannsdörffer zur Vollendung des 75. Lebensjahres gewidmet.  相似文献