Summary
The question of introducing systematic measurements of natural illumination into the operational commitments of the Radiation Service of the South African Weather Bureau received serious attention first during 1954. As a result of a planned programme of laboratory investigation, two new types of recorder were developed for the measurement of diffuse skylight as well as of the total hemispherical daylight. Altogether three instruments were constructed in the Weather Bureau workshop; these were brought into continuous operation on January 1, 1955.
This paper provides an account of the more important preliminary studies which were carried out in the radiation laboratory, at Pretoria, and also of the main characteristics of the recorders determined both in this manner and under conditions of natural exposure, at the central radiation observatory, over a period of 12 months.
A section is devoted to the techniques adopted for the standardization of the recorders and the reduction of the assembled traces. It is believed that several of the features introduced in these respects are quite new.
Zusammenfassung
Das Problem der Einführung systematischer Messungen der natürlichen Helligkeit in das Arbeitsprogramm des Strahlungsdienstes des Südafrikanischen Wetterbureaus wurde erstmals 1954 genauer geprüft. Im Rahmen eines Programmes für Laboratoriumsuntersuchungen wurden zwei neue Modelle von Registrierapparaten für die Messung des diffusen Himmelslichts und der Globalbeleuchtung auf Horizontalfläche entwickelt; insgesamt wurden in der Werkstätte des Wetterbureaus drei Geräte gebaut und ab 1. Januar 1955 in Dauerbetrieb genommen.
In der vorliegenden Arbeit wird über die wichtigeren, im Strahlungslaboratorium in Pretoria durchgeführten Vorstudien berichtet sowie über die Haupteigenschaften der Registrierapparate auf Grund von Untersuchungen im Laboratorium und unter natürlichen Bedingungen im Freien, die während einer Periode von 12 Monaten am zentralen Strahlungsobservatorium durch-geführt wurden. Sodann wird über die Technik der Eichung der Registriergeräte und über die Auswertung der Kurven referiert, wobei teilweise auch neue Gesichtspunkte zur Sprache kommen.
Résumé
C'est en 1954 que fut examinée pour la première fois l'introduction de mesures systématiques de la luminosité naturelle dans le programme de travail du Service de rayonnement du Service météorologique de l'Afrique du Sud. Dans le cadre d'un programme de recherches expérimentales, on a mis au point deux nouveaux modèles d'enregistreurs de la lumière diffuse du ciel et de la luminosité globale sur une surface horizontale; trois instruments ont été construits dans les ateliers du Service météorologique et mis en service continu dès le ler janvier 1955.
On rapporte ici sur les études préliminaires du laboratoire de rayonnement de Pretoria et sur les propriétés principales des enregistreurs sur la base des essais de laboratoire ainsi qu'en plein air effectués pendant douze mois à l'Observatoire central de rayonnement. Enfin on mentionne les procédés d'étalonnage et de dépouillement des courbes obtenues en discutant aussi de nouveaux points de vue.
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Drummond, A.J. Notes on the measurement of natural illumination. Arch. Met. Geoph. Biokl. B. 7, 437–465 (1956). https://doi.org/10.1007/BF02242970
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DOI: https://doi.org/10.1007/BF02242970