Comparison and significance of auroral studies during the Swedish and Russian bilateral expedition to Spitsbergen in 1899ndash;1900

摘要

Results of measurements and visual observations of aurora atSpitsbergen, carried out by the joint Swedish-Russian expeditionduring 1899–1900, are described. Auroral observations took placeduring the great bilateral Arc-of-Meridian expedition, which waspatronized by the Swedish Royal Family and the Russian ImperialFamily. The Russian-Swedish Arc-of-Meridian measurements wereclosely coordinated but auroral measurements from the two sites in theSpitsbergen Archipelago were almost independent of each other. Thebasic auroral data for our presentation are reports of the Russianastronomer Josef Sykora and the Swedish geophysicist Jonas Westman.Both scientists used similar types of photo cameras andspectrographs, which were the best at that time and were made inPotsdam by Toepfer. Detailed descriptions of the optical devices andthe system of spectral calibration are presented. A Toepferspectrograph, possibly the one used by Westman, is still kept at IRFin Kiruna. We present a comparative analysis of auroral data fromthe Russian and Swedish stations on three themes: visualobservations of aurora, describing features of auroral forms andgiving us statistical data on aurora occurrence and the heights ofaurora, photos of aurora, and auroral spectra. It is shown that theobservations contain enough data to construct an auroral oval andto determine the heights of aurora. The expedition obtained the firstphotographic observations of the aurora in the Arctic. The auroralspectra demonstrate a high spectral resolution and show not only themain auroral emissions in the blue-green spectral range but alsosome weak emissions in the violet and ultraviolet region. All dataare interpreted from a modern point of view. The Russian-Swedish1899–1900 expedition carried out the first complex auroralinvestigations in the Arctic using optical instruments and presentedwell documented data and new results.