Sull'approssimazione numerica di una variabile casuale normale,con applicaztone agli errori d'osservazione

Riassunto Data una variabile casuale X che segue la legge normale di probabilitl con valor medio a ed error medio y 1'A. considera un'altra variabile casuale che prende il valore intero r quando r–1/2

Summary Given a random variable X following the normal probability law, with expectation a and standard error p, the author considers another random variable , that takes the entire value r when r–1/2     

“Pandora box” — Matrix in the calculus of observations

Summary If the condition R(A)=k(n), whereA is the design matrix of the type n × k and k the number of parameters to be determined, is not satisfied, or if the covariance matrixH is singular, it is possible to determine the adjusted value of the unbiased estimable function of the parameters f(), its dispersion D( (x)) and ² as the unbiased estimate of the value of ² by means of an arbitrary g-inversion of the matrix . The matrix , because of its remarkable properties, is called the Pandora Box matrix. The paper gives the proofs of these properties and the manner in which they can be employed in the calculus of observations.     

Frequency-time analysis of geomagnetic beating-type pulsationsPc3

Summary The mechanism of beating of Pc3 type pulsations is studied. Using the method of numerical computation of a sonagram (the method of frequency-time analysis) a set of samples of pulsations from the Budkov Observatory is treated (1968–1969) mostly at K-indices equal to 2–3. By comparing f–t diagrams with the spectra of the samples an attempt has been made at interpreting the beating as a superposition of the frequency components, contained in the pulsation signal. In most observed cases it is possible to determine two close frequencies, the difference of which is on the average =5.4 mHz. The average carrier frequency of the samples was =37.6 mHz, and the average frequency of the beating =2.7 mHz. The interval of observed values of f_B amounted to 1–5 mHz. A tendency was observed for f_B to increase with increasing degree of disturbance of the geomagnetic field.     

Geoenvironmental problems of recreational use of the Ivankovo Reservoir

Methodical principles of recreational studies of reservoirs are discussed. The impact of main types of recreational water use on water quality is revealed using the Ivankovo Reservoir as an example.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 115–122.Original Russian Text Copyright © 2005 by Lantsova, Grigoreva, Tikhomirov.     

Ecotoxicological approach to water quality assessment

Comparative analysis of approaches and methods of biological assessment of water quality is presented. A method of ecotoxicological diagnostic of aquatic ecosystem health and water quality evaluation based on the physiological state of fish are substantiated. Characteristics of the main symptoms of diseases in fish inhabiting freshwater bodies and pathologic disturbances in their organs and tissues, caused by water bodies contamination with toxic substances, are presented. The method of ecotoxicological assessment of water quality is shown to be both highly informative and easy-to-use in practical monitoring.Translated from Vodnye Resursy, Vol. 32, No. 2, 2005, pp. 184–195.Original Russian Text Copyright © 2005 by Moiseenko.     

Prediction of water salinity in the Yumaguzinskoe Reservoir under construction

Factors responsible for the formation of water salinity in the Yumaguzinskoe Reservoir, which is under construction in the upper reaches of the Belaya River, are analyzed. Based on the prediction experience and a sufficient amount of initial data on water quality of the Belaya River, the universally accepted algorithm of prediction for years of different water supply levels using the calculation method of running-out has been modified. As revealed, the minimum water salinity at the reservoir spillway is observed in May–August, the maximum water salinity being in January–March. The regularities of a general nature have been found.Translated from Vodnye Resursy, Vol. 32, No. 2, 2005, pp. 214–222.Original Russian Text Copyright © 2005 by Popov, Oboldina.     

Mean equatorial gravity derived from various geopotential models

Summary Mean equatorial gravity has been computed from geopotential models GEM-10C, GEM-7, GEM-T1, GEM-T2, GEM-T3, JGM-1, JGM-2, JGM-3 and OSU91A and compared to the normal equatorial gravity, _e=978 032·699 × 10^–5 m s^–2, computed from four given parameters defining the Earth's level ellipsoid. In all models g_e>_e.     

Distribution and fluxes of metals in the St. Lawrence River from the outflow of Lake Ontario to Québec City

Six anchor stations in the St. Lawrence River from the outflow of Lake Ontario to Quebec City, were occupied for ca. 24 hours in June 1987 during low flow conditions. Samples of water and suspended particulate matter were separated by continuous-flow centrifugation, and were collected every two hours.During this sampling period, fluxes of dissolved forms of zinc, copper and nickel increased in Lac St. François and downstream relative to the sum of the fluxes for the two upstream stations at the outflow of Lake Ontario. Increases in the flux of dissolved zinc and copper were pronounced below Montreal and above Lac St. Pierre. For particulate forms of metals, all five metals show that there are significant inputs in the section of the St. Lawrence River between Lac St. François and the station just above the entrance to Lac St. Pierre.The average concentrations of dissolved cadmium, lead, zinc, copper and nickel ranged from 7–23 ng/l; 9–35 ng/l; 0.434–0.939 g/l; 0.15–0.89 g/l and 0.58–1.12 g/l respectively.Regression analysis of the dissolved and particulate metal concentrations suggests that the concentration of dissolved cadmium, lead, zinc and nickel can be predicted from the regression equation and the determination of particulate metal concentration. This prediction appears to be independent of the suspended particulate matter concentration which varies from ca. 1 to 10 mg/l from the outflow of Lake Ontario to Québec City.     

Some laboratory model experiments on the mechanism of two-dimensional momentum transfer in the atmosphere

Summary Investigating the jetstream formation in the upper troposphere, it becomes evident that two-dimensional transfer processes are, to a high degree, responsible for the accumulation of kinetic energy and momentum in those upper tropospheric regions. To shed light on these processes a series of barotropic model experiments has been carried out using a special dynamic procedure for vortex generation. In a large, rotating, cylindrical vessel (filled with water, rotation rate ₀) three smaller cylinders have been fitted eccentrically. Their rotation relative to the vessel (rotation rate _i ,i=1, 2, 3) produces a sharply limited narrow region around each of them, where a nearly two-dimensional relative motion can be observed. Beyond this region — we call it friction zone — there is no motion. Now if we impose some perturbation on this steady mean flow (e.g. by setting _i = 0) the zonal current breaks down into a definite number of vortices which show a random distribution. The dynamic behaviour of these nearly two-dimensional vortices can then be studied.The main results are: I) After the sudden breakdown of the friction zones the most intensive eddies, which are cyclonic, drift more or less directly towards the centre to be organized there into a larger vortex. This development is strongly influenced by the -effect and the ratio = _i /₀, which controls the supply of rotational energy. II) If there exists a steady zonal basic current, the vortices will be more and more deformed when approaching and penetrating the zonal flow until they are wholly incorporated.     

Anisotropy of Cs137 gamma-ray absorption in rocks

Summary The anisotropy of the Cs¹³⁷ gamma-ray absorption coefficient has been investigated in layered models and several rock samples. It was found that in contrast to other petrophysical parameters the gamma-ray absorption coefficient is characterized by a relatively small coefficient of anisotropy (3–5%). Therefore, the possible effect of the anisotropy can be neglected in the measurements of for rocks as it is usually below current observational errors.     

Analysis of Changes in the Aral Sea Coastal Zone in 1975–1999

Changes in the Aral Sea coastline and coastal zone over different time intervals during the period of the sea level drop are studied with the use of space photographs obtained from the orbital station Salyut-4 and satellites of the Resurs-O system. Interannual variations in the above characteristics are analyzed for 1975–1989, 1989–1993, 1993–1996, 1997, 1998, and 1999. Seasonal variations in the water area and coastal landscapes are studied with the help of photographic images of the sea made in different seasons, mainly in 1998.     

Hydrochemical and microbiological characteristics of the Gusino-Ubukunskaya group of water bodies

Results of hydrochemical and microbiological studies of five largest water bodies belonging to the Gusino-Ubukunskaya group are presented. Present-day environmental state of the ecosystem subject to anthropogenic load is described. The possibility of using water quality parameters of the investigated lakes as indicators of the degree of contamination of waters flowing into the Baikal Lake is shown.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 79–84.Original Russian Text Copyright © 2005 by Khakhinov, Namsaraev, Ulzetueva, Barkhutova, Abidueva, Banzaraktsaeva.     

Thermohaline analysis of the La Perouse Strait water

Sakhalinskii Shelf information and analytical GIS based on observational data is used to simulate hydrological parameter values at standard horizons of stationary stations in the La Perouse Strait. The spatial and temporal distribution pattern for oceanographic parameters has been obtained. Water masses and water structures have been identified using classic T, S-analysis. Volumetric T, S-analysis of waters is used to evaluate the volumes, heat content, and salinity of the water masses chosen. For the first time, information for the winter season, which is the least investigated season and for which no generalizations whatsoever have been made until the present, has been obtained.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 18–27.Original Russian Text Copyright © 2005 by Pishchalnik, Arkhipkin, Leonov.     

CUTLASS HF radar observations of high-latitude azimuthally propagating vortical currents in the nightside ionosphere during magnetospheric substorms

High-time resolution CUTLASS observations and ground-based magnetometers have been employed to study the occurrence of vortical flow structures propagating through the high-latitude ionosphere during magnetospheric substorms. Fast-moving flow vortices (800 m s^–1) associated with Hall currents flowing around upward directed field-aligned currents are frequently observed propagating at high speed (1 km s^–1) azimuthally away from the region of the ionosphere associated with the location of the substorm expansion phase onset. Furthermore, a statistical analysis drawn from over 1000 h of high-time resolution, nightside radar data has enabled the characterisation of the bulk properties of these vortical flow systems. Their occurrence with respect to substorm phase has been investigated and a possible generation mechanism has been suggested.     

Two-Dimensional Horizontal Numerical Model of Open Flow over a Bed with Obstacles

An explicit numerical algorithm for solving two-dimensional system of shallow-water equations is presented. The algorithm is based on the control volume method with recording mass and momentum fluxes through the faces of the volume with the use of an approximate solution of the Riemann problem. A numerical solution is compared with analytical solutions for a flow over a bottom step and with data of laboratory experiments in a flume with a sloped bed or a bed with an obstacle.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 282–294.Original Russian Text Copyright © 2005 by Prokofev.     

Ueber Herde elastischer Wellen in isotropen,homogenen Medien

Zusammenfassung 1) Es werden Multipollösungen der skalaren Wellengleichung ² f/t ² – c² div gradf=0 betrachtet. Einerseits kann man solche Lösungen direkt durch Kugelfunktionenn-ter Ordnung ausdrücken, anderseits aus der Einpollösungf=1/p F(t–p/c) durch Differentiation nachn Richtungen erhalten. Es wird der Zusammenhang zwischen den Ergebnissen der beiden Verfahren gezeigt. — 2) Für die Energiedichte und den Energiefluss durch Kugelflächen bei kleinen elastischen Verschiebungen werden Ausdrücke in Kugelkoordinaten angegeben. — 3) Für die Wellengleichung grad div –b ² rot rot werden rotationsfreie Multipollösungen angegeben und Ausdrücke für Energiedichte und Energiefluss hergeleitet. — 4) Das gleiche wird für divergenzfreie Multipollösungen durchgeführt. — 5) Es werden Multipole betrachtet, die weder rotationsfrei noch divergenzfrei sind. Als Spezialfälle werden Multipole mit zeitlich begrenzter und solche mit periodischer Erregung gezeigt, ferner Lösungen der Wellengleichung, die sowohl rotationsfrei wie divergenzfrei sind. — 6) Es wird gezeigt, wie man die elastischen Wellen, die im Sinne vonStokes von einem Herdgebiet endlicher Ausdehnung ausgehen, näherungsweise durch elastische Multipole darstellen kann. — 7) Es wird angedeutet, wie man durch Messung von Komponenten von oder u.s.w. in Punkten im Innern des Mediums die Erregung und Energie von elastischen Multipolen bestimmen kann. Ferner wird auf den Fall hingewiesen, wo ein rotationsfreier Einpol sich im Innern eines Halbraumes befindet und die Messungen an seiner Oberfläche ausgeführt werden.

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Summary (On foci of elastic waves in isotropic homogeneous media) — 1) Multiplets as solutions of the scalar wave equation ² f/t ² – c² div gradf=0 are considered. Such solutions can be obtained either directly by aid of spherical harmonics of ordern, or by differentiating the single polef=1/p F(t–p/c) with respect ton directions. The relations between the results of those two procedures are shown. — 2) In the case of small elastic displacements , the density of energy and the flow of energy through spherical surfaces are expressed by spherical coordinates. — 3) Multiplets which satisfy the equation of motion =a ² grad div b ² curl curl and the equation curl = 0 are given, and expressions for the density and flow of energy are found. — 4) The same is done with multiplets satisfying the equation of motion and the equation div = 0. — 5) General multiplets which satisfy the equation of motion are treated. As special cases, multiplets with excitation of finite length and multiplets with periodic excitation are considered, furthermore solutions of the equation of motion and of the equations curl = 0 and div = 0 are given. — 6) It is shown how elastic waves whose origin is a region of finite extension in the sense given byStokes, can be approximated by elastic multiplets. — 7) Some indications are given on the problem of how to find the functions of excitation and the energy of an elastic multiplet by measuring components of or etc., at points in the interior of the medium. The same problem is considered in the case of the single elastic pole. = grad 1/p F (t–p/a), if the measurements are made at the surface of an elastic half space.

     

Comparative soil CO2 flux measurements and geostatistical estimation methods on Masaya volcano, Nicaragua

We present a comparative study of soil CO₂ flux () measured by five groups (Groups 1–5) at the IAVCEI-CCVG Eighth Workshop on Volcanic Gases on Masaya volcano, Nicaragua. Groups 1–5 measured using the accumulation chamber method at 5-m spacing within a 900 m² grid during a morning (AM) period. These measurements were repeated by Groups 1–3 during an afternoon (PM) period. Measured ranged from 218 to 14,719 g m⁻² day⁻¹. The variability of the five measurements made at each grid point ranged from ±5 to 167%. However, the arithmetic means of fluxes measured over the entire grid and associated total CO₂ emission rate estimates varied between groups by only ±22%. All three groups that made PM measurements reported an 8–19% increase in total emissions over the AM results. Based on a comparison of measurements made during AM and PM times, we argue that this change is due in large part to natural temporal variability of gas flow, rather than to measurement error. In order to estimate the mean and associated CO₂ emission rate of one data set and to map the spatial distribution, we compared six geostatistical methods: arithmetic and minimum variance unbiased estimator means of uninterpolated data, and arithmetic means of data interpolated by the multiquadric radial basis function, ordinary kriging, multi-Gaussian kriging, and sequential Gaussian simulation methods. While the total CO₂ emission rates estimated using the different techniques only varied by ±4.4%, the maps showed important differences. We suggest that the sequential Gaussian simulation method yields the most realistic representation of the spatial distribution of , but a variety of geostatistical methods are appropriate to estimate the total CO₂ emission rate from a study area, which is a primary goal in volcano monitoring research.Editorial responsibility: H Shinohara     

Noto pri devigata movado de lineara oscilatoro

Summary Frequency characteristics of a linear oscillator or a seismometer, whose equation of free oscillation is +n ² x=0, are usually represented by takingh(=/n) as parameters. In this case, however, the independent variable is the frequency of impressed force or displacement from outside on the oscillator. But, we often encounter those cases, where the frequencies from outside are constant, and the frequency of the oscillator or pick-up is to be changed, or the several oscillators with various frequencies are to be used. Then, of course,h cannot be taken as parameters, as they vary with the oscillator's frequencyn. The author here calculated the amplitude- and phase-characteristics for the latter case, taking (=/n) as parameters and represented them in thick lines in the figures together with the ordinary ones in thin lines.

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Résumé On rencontre souvent des problèmes où divers oscillateurs dé périodes propres différentesT _0j et de même coefficient d'amortissement , sont attaqués par un phénomène sinusoïdal de périodeT. Les courbes classiques qui donnent l'amplitude et la phase du mouvement forcé en fonction du rapportT/T ₀ pour différentes valeurs du paramètreh=T ₀/2, ne peuvent alors être utilisées. Nous donnons ici les courbes correspondant à des valeurs différentes du paramètreh(=/n)= T/2.

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International language: Esperanto.     

On spectral extinction of solar radiation within a tropical atmospheric boundary layer

Helicopter measurements of solar irradiance and meteorological data within the atmospheric boundary-layer were made in Lagos during February 1979. Filter samples of aerosols were collected both during flight in February 1979 and at ground level in December 1978. Profile data on spectral aerosol optical depth were obtained and, from these, the aerosol extinction coefficient at two wavelengths (0.5 and 0.88 m) were calculated. Precipitable water was low and was contained mainly within the 750 m layer above ground, suggesting the establishment of a deep unstable boundary layer. Calculated channel energy depletions by aerosols show that, within the first 750 m of the surface, the 0·88 m might be more efficient at attenuating solar energy than 0·5 m. The lagoon (maritime) aerosol sample indicated a more monodisperse size-distribution than the dusty harmattan aerosol sample.     

Variations in the Hydroecological Characteristics of Water Masses in the Central Pool of the Mozhaisk Reservoir

Results of a special experiment conducted in the summer of 2002 in the Central pool of the Mozhaisk Reservoir are discussed. The experiment was aimed at studying short-period and small-scale variations in water temperature, electric conductivity, transparency, dissolved oxygen content, total and mineral phosphorus, phyto-, microzoo- and zooplankton. Statistical characteristics of the above-mentioned environmental parameters are presented.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 352–360.Original Russian Text Copyright © 2005 by Datsenko, Edelshtein, Goncharov, Puklakov, Chernega.