Forward–backward scheme on the B/E grid modified to suppress lattice separation: the two versions, and any impact of the choice made?

Ever since its introduction to meteorology in the early 1970s, the forward–backward scheme has proven to be a very efficient method of treating gravity waves, with an added bonus of avoiding the time computational mode of the leapfrog scheme. It has been and it is used today in a number of models. When used on a square grid other than the Arakawa C grid, modification is or modifications are available to suppress the noise-generating separation of solutions on elementary C grids. Yet, in spite of a number of papers addressing the scheme and its modification, or modifications, issues remain that have either not been addressed or have been commented upon in a misleading or even in an incorrect way. Specifically, restricting ourselves to the B/E grid does it matter and if so how which of the two equations, momentum and the continuity equation, is integrated forward? Is there just one modification suppressing the separation of solutions, or have there been proposed two modification schemes? Questions made are addressed and a number of misleading statements made are recalled and commented upon. In particular, it is demonstrated that there is no added computational cost in integrating the momentum equation forward, and it is pointed out that this would seem advantageous given the height perturbations excited in the first step following a perturbation at a single height point. Yet, 48-h numerical experiments with a full-physics model show only a barely visible difference between the forecasts done using one and the other equation forward.     

Silica-bearing magnetites

Some varieties of magnetite with relatively high content of SiO₂ (about 5,4%) were found by the authors. Silica-bearing magnetite of the Korshunovskoye scarn deposit is enriched in Ca (up to 1.99% CaO), Al, Mg, Ti. In serpentinites of the Atlantic and Indian oceans Si-magnetite forms pseudomorphs on Cr-spinel and includes impurities of Mn (to 3.5% MnO), Cr, Mg and Al. Distinct quantitative correlations of silica and other trace elements are observed. The authors suggest possible models of cation distribution in Si-magnetites and suppose that emplacement of silica into the magnetite crystal structure is due to the presence of chlorine in mineral-forming solutions.     

Über die Entwicklung magnetischer Fernkompasse in Deutschland

Zusammenfassung Es werden die Umstände angegeben, die für die Entwicklung von magnetischen Fernkompassen maßgebend waren, und die Forderungen erwähnt, denen solche Geräte genügen müssen. Zwei Haupttypen lassen sich unterscheiden: der primäre, der die für die Betätigung von Anzeigeinstrumenten notwendigen Meßgrößen (z. B. elektr. Spannungen) aus dem magnetischen Erdfeld direkt gewinnt, und der sekundäre, bei dem diese Meßgrößen auf dem Wege über ein Magnetnadelsystem erzeugt, in verschiedener Weise umgeformt und auf Tochterkompasse übertragen werden.Aus der Vielfalt der in Deutschland entwickelten Geräte werden Aufbau und Wirkungsweise einer Reihe typischer Konstruktionen näher beschrieben; ihre speziellen Vorzüge und Nachteile werden besprochen.

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On the development of magnetic telecompasses in Germany

Summary The author describes the conditions which have decisively influenced the development of magnetic telecompasses and states the demands such instruments have to meet. The telecompasses may be divided into two categories, viz: The direct compass which directly receives the quantities to be measured (e. g. electrial voltages) which are necessary for operating the indicating or repeater instruments from the earth's magnetic field and the indirect compass in which these quantities are produced by the aid of a system of magnetic needles and transformed in different ways in order to be finally transmitted to the repeater compasses.From the many types of magnetic telecompasses developed in Germany a number of typical constructions is described in detail and their special advantages and deficiencies are discussed.

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Sur les systèmes de télécompas magnétiques développés en Allemagne

Résumé L'auteur décrit les circonstances qui ont décisivement influencé le développement des télécompas magnétiques et traite les besoins auxquels ces appareils doivent répondre. Les télécompas se répartissent en deux types principaux: Le type direct qui reçoit immédiatement du champ magnétique terrestre les valeurs à mesurer (p. e. les tensions électriques) nécessaires pour la mise en fonction des compas indicateurs, et le type indirect qui est muni d'un système d'aiguilles magnétiques pour la production de ces valeurs qui sont transmises aux compas répétiteurs après avoir été transformées de manières différentes.De la multiplicité des télécompas développés en Allemagne quelques constructions typiques sont choisies dont on précise la structure et le fonctionnement et expose les avantages ainsi que les inconvénients particuliers.

     

Ultraviolet observations in Puppis with the space telescope ‘Glazar’

The results of observations of 159 stars at 1640 Å in Puppis made with the space telescope Glazar are presented. It is shown that the observed stars are members of different groups of stars situated at distances of about 120, 370, 700, 1250, 2400, and 4000 pc. The last two groups belong to the Pup OB1 and the Pup OB2 stellar associations.There is relatively little absorption in the observed region. The absorbing matter is mainly concentrated in small clouds.It is suggested that three stars — CP –27°4197, HD 60479, and HD 61672-are embedded in a dust envelope and that the star HD 60057 has a hot subdwarf companion.Forty-four of the observed stars are new OB or early A-type stars, spectral types of which were not known.     

Orbits of the visual binaries ADS 8814 and ADS 8065 from observations along a short arc

The orbits of the visual binaries ADS 8814 and ADS 8065 are determined for the first time. The orbits were calculated using the parameters of the apparent motion, based on position observations along short arcs obtained on the 26-inch refrector of the Pulkovo Observatory, supplemented with radial-velocity observations for the stellar components in both pairs obtained on the 1-m telescope of the Simeiz Section of the Crimean Astrophysical Observatory. All previous visual and photographic observations of these stars after 1832 were also taken into account. The orbit of ADS 8814 was refined using the differential-correction method. The orbital periods of these two stars are about 800 and 6000 years, respectively. The mass estimates derived for the known parallaxes from the Hipparcos catalog correspond to the spectral types of these stars. The polar vectors of the obtained orbits in Galactic coordinates are also given.     

Accurate relative positions and motions of poorly studied binary stars

We have studied the relative motions of the components of 25 visual binary and multiple stars for which only a modest number of observations of various types had accumulated due to their small relative component motions. A uniform series of photographic observations obtained over many years on the 26-inch refractor of the Pulkovo Observatory are used to calculate the parameters of the apparent relative positions and motions, which can be used for further kinematic and dynamical studies of these stars. A comparison of the relative and proper motions of the components indicates that they are physically bound. Optical components are identified in six systems??for the first time in the three systemsWDS00082+6217, ADS 830, and ADS 7361. The relative motions in ADS 861 and ADS 12925 suggest the presence of perturbing invisible companions, but this requires confirmation based on more accurate observations. The apparent motion parameters method yields a family of orbits with a minimum period of 26 000 yrs for the nearby wide visual binary Gliese 745, for which the parallax and relative radial velocity of the components are known.     

Lake Shira Level Changes in Late Holocene

正1 Introduction Meromictic Shira Lake is a good represfor detail climate modeling due to its locainformation and annually laminated bottomsediment column of 155 cm in length wahammer corer in the deepest(24 m)central in 2009.2 Sample Preparations and Measuring     

Orbits of four visual binaries determined from observations along short arcs

The orbits of the four visual binaries ADS 246 (GL 15), ADS 7724 (γ Leo), ADS 10386 (GJ 659), and ADS 14909 (1 Peg) have been determined using the apparent motion parameters (AMP) method. The orbital periods of these stars are 1200, 550, 7500, and 18 000 yr, respectively. The orbits were calculated based on observations along short arcs obtained with the 26-inch refractor of the Pulkovo Observatory and Hipparcos parallaxes, supplemented with radial-velocity measurements for the components of these pairs taken from the literature. All visual and photographic observations of these stars after 1830 from the WDS catalog have been taken into consideration. The new orbits of ADS 246 and ADS 7724 are compared with the orbits computed in other studies. The orbits of ADS 10386 and ADS 14909 have been determined for the first time. The orientation of the planes of the computed orbits in Galactic coordinates have also been calculated.