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

Abstract

Abstract. Results of measurements and visual observations of aurora at Spitsbergen, carried out by the joint Swedish-Russian expedition during 1899–1900, are described. Auroral observations took place during the great bilateral Arc-of-Meridian expedition, which was patronized by the Swedish Royal Family and the Russian Imperial Family. The Russian-Swedish Arc-of-Meridian measurements were closely coordinated but auroral measurements from the two sites in the Spitsbergen Archipelago were almost independent of each other. The basic auroral data for our presentation are reports of the Russian astronomer Josef Sykora and the Swedish geophysicist Jonas Westman. Both scientists used similar types of photo cameras and spectrographs, which were the best at that time and were made in Potsdam by Toepfer. Detailed descriptions of the optical devices and the system of spectral calibration are presented. A Toepfer spectrograph, possibly the one used by Westman, is still kept at IRF in Kiruna. We present a comparative analysis of auroral data from the Russian and Swedish stations on three themes: visual observations of aurora, describing features of auroral forms and giving us statistical data on aurora occurrence and the heights of aurora, photos of aurora, and auroral spectra. It is shown that the observations contain enough data to construct an auroral oval and to determine the heights of aurora. The expedition obtained the first photographic observations of the aurora in the Arctic. The auroral spectra demonstrate a high spectral resolution and show not only the main auroral emissions in the blue-green spectral range but also some weak emissions in the violet and ultraviolet region. All data are interpreted from a modern point of view. The Russian-Swedish 1899–1900 expedition carried out the first complex auroral investigations in the Arctic using optical instruments and presented well documented data and new results.

The Arc-of-Meridian Expedition to the Spitsbergen Archipelago 1899-1901 as an example of international scientific collaboration: tasks and results

“…Observation of aurora borealis during the expedition held by J. Sykora and J. Westman allowed determining the height of the northern lights and its shape and speed. As it was the first study conducted using modern instruments, the obtained data was the beginning of a new era in the understanding the phenomenon [14]. Moreover, the topography of the centre, north, and northeast of Spitsbergen was introduced by G. De Geer and his team during the expedition [15].…”

Inter-academic cooperation in the Arctic during the 1898–1901 Swedish–Russian Arc-of-Meridian expedition: Based on materials from the Russian Academy of Sciences Archives

“…Observations about the northern lights were carried out including photographic recording of the auroras and their spectra using the world's best photographic and spectral optical equipment at that time. Continuous magnetic observations and systematic meteorological observations were made, providing new scientific data (Commission of the Academy of Sciences for Degree Measurement on the Spitsbergen Islands, 1900; Chernouss & Sandahl, 2008).…”

Fine structure of optical aurora

“…To be able to record weak emissions also very long exposure times were used. In auroral studies in Spitsbergen 1899-1900 by Jonas Westman and Josef Sykora exposure times from 1 to as much as 28 h were used (Chernouss and Sandahl, 2008).…”