ALBERT

Description / Table of Contents: Summary The squares of critical frequencies (f 0 F 2)2 measured at European stations in the morning of a summer-month may be represented by a formula $$(f_0 F_2 )^2 = K.\left( {\frac{{\cos \chi }}{{cos^2 \varphi }}} \right)^x .cos^2 \varphi .$$ Herein χ is the zenithangle of the sun, ϕ the geographical latitude of the ionospheric station.α depends on locality, butK is independent on it and probably characteristic of intensity of the sun's ionizing radiation.

Description / Table of Contents: Summary In the ionospheric F-layer the electron densityn increases with the formulan=a. cosχ+b in the morning (χ is meaning the zenithangle of the sun). This experimental result may be explained by consideration of earth-curvature and by assumption of a linear recombination-law equally an attachment process. The constantsa andb vary with season and location. We conclude the temperature from these variations and we find for polar locations a greater temperature in the summer and on the other hand a smaller temperature in the winter as for temperate latitudes.

Description / Table of Contents: Zusammenfassung Das seinerzeit nur für dieF1-Schicht aufgestellte Modell wird so erweitert, daß eine Deutung beiderF-Schichten möglich wird. Wesentliche Voraussetzungen sind: Ionisierung eines einzigen Bestandteiles der Luft durch eine monochromatische Strahlung. Ein positiver Temperaturgradient im Bereich derF1-Schicht, eine höhen-unabhängige Temperatur im Bereich derF2-Schicht und ein negativer Temperaturgradient oberhalb des Ionisationsmaximum, derF2-Schicht. Weiters wird vorausgesetzt, daß der Elektronenvernichtungsprozeß in derF1-Schicht dem Quadrat der Elektronendichte proportional sei, in derF2-Schicht soll er dagegen der Elektronendichte einfach proportional sein. Eine Abhängigkeit dieses Prozesses von derk-ten Potenz des Druckes,p und von dern-ten Potenz der absoluten TemperaturT wird hier vom ursprünglichenF1-Schicht-Modell übernommen. Erst die genannten Annahmen über die Temperaturverhältnisse machen den beobachteten Übergang von statischen zu dynamischen Verhältnissen in derF2-Schicht verständlich. Während der Nacht und am Morgen bis in die ersten Vormittagsstunden kann dieF2-Schicht als statisches Problem behandelt werden, die Bewegungsvorgänge der Luftmassen spielen eine nur untergeordnete Rolle. Darnach aber ruft eine labile Schichtung der Luftmassen kräftige Luftbewegungen hervor, sodaß dieF2-Schicht nur mehr als dynamisches Problem mit besonderer Berücksichtigung von Luftmassenverschiebungen behandelt werden kann. Zahlreiche Beobachtungsdaten werden herangezogen, um die Anwendbarkeit des neuen Modells zu beweisen und um mit Hilfe des Modells zu neuen Aussagen zu gelangen. Es gelingt so z. B., den Jahresgang der Temperatur in einem konstant gehaltenen Druckniveau derF1-Schicht anzugeben. Eine kritische Betrachtung der Modelle, die in letzterer Zeit von anderen Autoren veröffentlicht wurden, beschließt die Arbeit.

Description / Table of Contents: Zusammenfassung Jüngste Untersuchungen (1,2) der Ionosphäre mit Hilfe ultrakurzer Wellen, die am Mond reflektiert werden und beim zweimaligen Durchgang durch die Ionosphäre eine Drehung ihrer Polarisationsebene erfahren, gestatten Aussagen über den gesamten Ekektronen-Inhalt der ionosphärischen Schichten. Damit ergibt sich nicht nur eine willkommene Erweiterung unserer Meßmethodik, die sich ja mit der bisherigen Echolotung auf die Unterseite der Ionosphärenschichten beschränken mußte, sondern auch eine neue Möglichkeit, die Brauchbarkeit des kürzlich vonBurkard (3) zur Diskussion gestellten Modells zu überprüfen. An Hand dreier ausgewählter Fälle, für die die Elektronenverteilung mit der Höhe explizit berechnet wurde, kann die gute Übereinstimmung zwischen Modell und Beobachtungsdaten nachgewiesen werden, woraus man schließen darf, daß die Modellvorstellungen recht gut den tatsächlichen Verhältnissen in der oberen Atmosphäre entsprechen.

Description / Table of Contents: Summary Starting-point for our study was the static balance equation where the electron production is equated to the effective recombination. For the latter process we use the generally valid formula $$L = \alpha _0 \cdot p^k \cdot T^n \cdot N^{m + 2} $$ as introduced byBurkard. It was one of our first tasks to find appropriate numerical values for the constantsk, m, n. Thereby the following possibility presented itself: TheN(h) profiles derived from observations are represented in power series, that is in powers of «x», wherex designates the height from the layer peak upwards. Similarly, we can also set up such power series for the scale heightH, the pressurep and the density ρ. A comparison of coefficients thus should enable us to computeH (h) profiles. It turned out, however, in the course of this study that the accuracy of the observational material [e.g. theN (h) profiles at hand] is not sufficient for such a comparison of coefficients, so that we had to look for other ways. We were finally successful in determining from the observational material the numerical values for the hitherto undefined constantsk, m, n. Here two different possibilities result, according as we assume quasi-recombination or quasi-attachment. In many cases, so for instance in the derivation ofH (h) profiles, it did not prove necessary to decide upon one of these two possibilities, so that the computed values are valid for both models. One fact is probably of special importance, namely that the process of electron loss is found as a linear function of the temperature of the neutral gas (or the electron gas). Here further studies will be necessary, in order to interpret this result on the basis of molecular or atomic theory. The model presented in this study is mainly based onN (h) profiles, but agreement is also excellent with observations obtained by the moon-echo method, moreover, with determinations of density derived from satellite orbits. In this connection valuable information is obtained fromH (h) profiles which were computed for many cases and which show the diurnal variation of the scale height. Additional calculations were performed in order to determine the seasonal variation of the scale height at least basically. TheH (h) profiles show that at a height of about 200 km a considerable increase in temperature can be observed in the daytime. There the scale height varies between about 80 km and 170 km (Station Puerto Rico, July). At higher altitudes, however, those variations are considerably smaller, amounting to only about 30 km. In these altitudes we also find gradients of the scale height whose derivation from zero is very slight. Calculation of anN (h) profile obtained by the Scatter-Radar-Method (Bowles) yielded an almost constant scale height from a height of about 340 km upwards to altitudes of 700 km. Seasonal variations, however, proved to be much higher. For the layer maximum under consideration relatively small values for the scale height were found for winter-time and values 1.4 times larger for summer-time. Also the diurnal variation at a height of about 200 km is much less noticeable in the winter-time. The maximum of the scale height changes its height also with the time of the day and the year reaching its maximum at summer noons. Since the present study deals with models only, some of the expressions used for calculation had to suffer a few neglects in order to avoid unnecessary complications. Thus the variation of gravity with height was neglected. Also the diffusion of electrons was not taken into account and present results indicate that those processes of diffusion do not prove as important as is generally assumed. In conclusion we make a few suggestions as to an effective continuation of the investigations reported here.

Description / Table of Contents: Summary Up to now measurements of atmospheric electricity have been carried out as a rule with the aid of dry batteries which offer many advantages particularly for this purpose. However, in case of continuous records the rather high prize and relatively short life of dry batteries must be taken in account, especially if tensions of several hundreds volts are needed. This was the underlying idea for the construction of an apparatus, described in this article, which allows to draw currents and tensions for atmospheric electricity measurements from the A. C. power supply.