Newly Digitized Data From Scandinavian Magnetometer Array Network Shows Large Regional Differences in Magnetic Environment

• Published in: Journal of Geophysical Research: Space Physics
• Main Authors: Kärhä, O., Tanskanen, E. I.
• Other Authors: University of Oulu, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University
• Format: Article in Journal/Newspaper
• Language: English
• Published: WILEY-BLACKWELL 2022
• Subjects: digitization; magnetic storm; magnetogram; magnetometer; Scandinavian magnetometer array; substorm; San Juan; Abisko; Kalle; Rostadalen
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/115785; https://doi.org/10.1029/2022JA030311

Funding Information: This work was supported by ReSoLVE Center of Excellence funded by the Academy of Finland (projects 272157 and 307411); FLEX-EPOS & G-EPOS infrastructures within EPOS and FIN-EPOS (numbers 293488, 311714, and 328778); and Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters. The authors thank Markku Mäkelä for the design and construction of the custom-built digitization device DigiMAG. O. Kärhä thanks Pyry Peitso, Mika Väänänen, Tero Raita and Hermann Opgenoorth for helpful conversations and guidance. The authors are grateful for NASA's Space Physics Data Facility for space-borne data. The key persons behind the IMP-8 data sets are Adam Szabo, Ron Lepping, and Norman Ness. The authors thank the geomagnetic observatories Kakioka [JMA], Honolulu and San Juan [USGS], Hermanus [RSA], INTERMAGNET, and many others for their cooperation to make the final Dst index available. The authors are thankful for the Geological Survey of Sweden for maintaining Abisko magnetometer. The International Magnetospheric Study (IMS) took place from 1977 to 1979. An objective was to study the magnetosphere at different heights on the Earth and in space simultaneously. The Scandinavian Magnetometer Array (SMA), where a dense magnetometer array was placed in the northern part of Scandinavia, was part of the IMS. This array extended 1,570 km in north-south and 1,290 km in east-west directions. The SMA-magnetometers contained a camera with 35 mm film and three wire-suspended magnets. These instruments recorded the movement of the magnets optically on the film. The usability of the SMA data has been limited by time-consuming digitization by hand. Thus, most of the recordings has been left nondigitized and unstudied. We have developed a method, named DigiMAG, to digitize the SMA recordings by using a custom-built device. This article presents the high-latitude dynamics of the strongest magnetic storm in 1977 between October 26 and 30. We analyze newly digitized data from Rostadalen ...