Die geodätsiche Anwendung der Sonnenfinsternisse

Summary The recording of the contact times of a solar eclipse on two stations provides a geodetic measurement of the arc between the stations. The applications of this idea hitherto undertaken and the relevant apparature are briefly summarized. Some experiences obtained at the measuring of the records and at the computing of the results are described.     

The criterion of dynamic stability of zonal motion including the vertical shear

Summary Many writers treated on the problem of dynamic instability of westerly flow due to the excessive horizontal shear, and the present author discusses the corresponding dynamic instability due to the vertical shear. The critical vertical shear in indifferent stratification is given by the condition — the meridional component of absolute vorticity vanishes, — and is an approximate negative valueof 10^–4 sec ^–1 in middle latitude. However the critical vertical shear in normal stable stratification is a fairly large negative value of 2 sec^–1. It might be emphasized that the problem of this study differs fromRichardson's criterion of turbulence, for the present author discusses the condition under which the zonal flow is dynamically stable, whileRichardson expressed the condition under which the turbulence will decrease.     

Bericht über die Tagung der Meteorologischen Gesellschaft in Hamburg vom 25. bis 29.10.1950

Ohne Zusammenfassung     

Buchbesprechungen

Ohne Zusammenfassung     

Die wirkliche Solarkonstante

Zusammenfassung Die Solarkonstante 2.4 wird begründet.

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Summary The true solar constant 2.4 is proved.

     

Erwiderung zu dem Aufsatz von Dr. Georgi: Das neue Absolut-Pyrheliometer von Prof. K. Wegener

Ohne Zusammenfassung     

Rappresentazione di curve spaziali materializzate

Riassunto Per rappresentare una curva spaziale su un piano si può piegare un filo metallico secondo la curva e fotografarlo, operazione che però richiede molto tempo. Nel presente articolo l'A. illustra un dispositivo ottico che, sostituito alla matita della tavola di egresso della macchina diBush, è atto a descrivere su pellicola una curva simile all'immagine fotografica del filo. In questo studio si sono considerati soltanto i casi in cui la sorgente di luce che illumina la è all'infinito o nella origine delle coordinate, mentre il punto di vista à sempre all'infinito.

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Summary One may represent a spatial curve on a plane by bending a metal thread along the curve and then photographing it, but in this way much time is wasted. In the present paper the A. suggests an optical device which, replaced to the pencil of the out-put table ofBush's machine, traces on film a curve that should look like the photographic image of the thread. In this study were taken into account only the cases in which the light source lighting , is at the infinite or in the coordinate origin, while the point of view is always at the infinite.

     

Die gravitationelle Deklination,ihre Bestimmung und ihre Elimination

Summary The gravitational declination appears here as the analogue of the wellknown magnetic declination. The photographic recording theodolit in connection with a high frequency impulse transmitter allows, by a method of simultaneousness on two fieldstations, its direct and connected measurement and its elimination with regard to geodetic directions. The method has been based on linear equations, with the only request of horizontal angle measurements to a plain system of stars, abstracting from any transportable clocks. The method promises a higher accuracy and a multiple as great working velocity, comparatively to the state at present.

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Résumé Le déclinaison gravitationelle apparaît ici comme analogue à la déclinaison magnétique. Le théodolite photographique enrégistreur utilisé avec des signaux horaires radiotélégraphiques spéciaux permet par une méthode de simultanéité, appliquée à deux stations de campagne, sa détermination et son élimination rélativement à des directions géodésiques. La méthode est basée sur des équations linéaires et ne demande que des mesures horizontales par rapport à un système simple d'étoiles sans avoir recours aux pendules transportables. Elle fournit probablement une exactitude bien améliorée et une vitesse plusieurs fois plus grande comparées à l'état actuel.

     

Meteorologische Faktoren bei der Ausbreitung ultrakurzer Funkwellen

Zusammenfassung Aus der formalen Aehnlichkeit des Brechungsquotienten (refraction index) für Licht und Ultrakurzwellen (short radio waves) lassen sich gemeinsame Gesichtspunkte für die Ausbreitung des Lichtes und der UK-Wellen (short waves propagation) entwickeln. Anomale Refraktion der Radiowellen insbesondere aussergewöhnliche Reichweite (superrefraction) lassen sich auf diese Weise leicht deuten. Es bestehen hierbei enge Beziehungen zum Aufbau der jeweiligen Grundschicht, wobei erdgebundene Führungen (ground based ducts) auf interne Grenzschichten dicht über der Erdoberfläche, abgehobene Führungen (elevated ducts) auf anomale Refraktion in der Peplopause einer Grundschicht vom Typ A, B oder C zurückzuführen sind. Grundschichten mit einer höher gelegenen Peplopause (Typ D oder E) kommen für eine Führung (duct) nicht mehr in Frage.

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Summary Formal similarity of refraction indices for light and for ultrashort radio waves permits developing common viewpoints of light and of short wave propagation. Thus, anomalous refraction of radio waves, especially superrefraction, is easily explained. With the existing close relations to the structure of the appropriate ground layer, ground based ducts will be traced back to internal limiting layers immediately above the earth's surface, and elevated ducts to anomalous refraction within the peplopause of a Type A, B and/or C ground layer. Ground layers with more elevated peplopause (Types D and/or E) are out of the question for ducts.

     

Hochtemperatur-Plagioklas im Meteorit von Oldenburg

Zusammenfassung Der Plagioklas im Meteorit von Oldenburg (10. 9. 1930) zeigt Hochtemperaturoptik, die damit auch für weitere Chondrite wahrscheinlich ist. Zusammensetzung ist An₁₁, 2V = 60 1/2°, = 1,5365, Auslöschungsschiefe 7 1/2°, Winkel zwischen und der 0-Stelle der Auslöschung 24°, Winkel zwischen [001] und = 20°. Anteil 6%, Verzwillingung sehr eng nach dem Albit- und Periklingesetz. Die Indikatrix wird mit den bisherigen Werten für die Hochtemperaturoptik verglichen.