Low-latitude Aurorae during the Extreme Space Weather Events in 1859

Abstract

The Carrington storm (September 1/2, 1859) is one of the largest magnetic storms ever observed and it has caused global auroral displays in low-latitude areas, together with a series of multiple magnetic storms during August 28 and September 4, 1859. In this study, we revisit contemporary auroral observation records to extract information on their elevation angle, color, and direction to investigate this stormy interval in detail.We first examine their equatorward boundary of "auroral emission with multiple colors" based on descriptions of elevation angle and color. We find that their locations were 36.5° ILAT on August 28/29 and 32.7° ILAT on September 1/2, suggesting that trapped electrons moved to, at least, L~1.55 and L~1.41, respectively. The equatorward boundary of "purely red emission" was likely located at 30.8° ILAT on September 1/2.If "purely red emission" was a stable auroral red arc, it would suggest that trapped protons moved to, at least, L ~ 1.36. This reconstruction with observed auroral emission regions provides conservative estimations of magnetic storm intensities. We compare the auroral records with magnetic observations. We confirm that multiple magnetic storms occurred during this stormy interval, and that the equatorward expansion of the auroral oval is consistent with the timing of magnetic disturbances. It is possible that the August 28/29 interplanetary coronal mass ejections (ICMEs) cleared out the interplanetary medium, making the ICMEs for the Carrington storm on September 1/2 more geoeffective.

Temporal and Spatial Evolutions of a Large Sunspot Group and Great Auroral Storms Around the Carrington Event in 1859

“…For the auroral visibility, we consulted the observational reports in the yearbook of the Russian Central Observatory (Kupffer, ) and the Armagh Observatory (MS 117; see Butler & Hoskin, ), newspapers in Portugal, Spain, Australia, New Zealand, and Brazil, and further Japanese diaries and Mexican newspapers (see supporting information Texts S2.1–S2.5). We then compare them with the known records reviewed in Hayakawa, Ebihara, Hand, et al (): reports in contemporary scientific journals ( American Journal of Science and Wochenschrift für Astronomie, Meteorologie und Geographie ; see Heis, , ), ship logs (see Green et al, ; Green & Boardsen, ), Australian records (see Humble, ; Neumeyer, ), newspapers in Spain and Mexico (see Farrona et al, ; González‐Esparza & Cuevas‐Cardona, ), Scandinavian reports (see Rubenson, , ; Trombolt, ) and East Asian historical documents (see Hayakawa et al, , Hayakawa, Ebihara, Hand, et al, ). We compute MLAT of the observing sites in the reports, based on the archaeomagnetic field model GUFM1 model covering the position of magnetic dipoles from 1590 to 2000 (Jackson et al, ).…”

“…The large sunspot group (Group 520 in Carrington, Group 143 in Schwabe, and Group 219 in Secchi) caused a series of ICMEs, and a subsequent series of magnetic storms and auroral displays between 28 August and 4 September 1859 (Green & Boardsen, ; Hayakawa, Ebihara, Hand, et al, ; Kimball, ; Lakhina et al, ; Lakhina & Tsurutani, ).…”

“…We have integrated these recovered auroral reports from Russian, Irish, Portuguese, Oceanian, Mexican, and Japanese documents with the previously known datable auroral reports (see e.g., Green & Boardsen, ; Hayakawa, Ebihara, Hand, et al, ; Kimball, ). Note that the Russian Empire ruled Alaska at that time and had preserved a report at Sitka in Alaska.…”

“…Their auroral records were concentrated in the Western Hemisphere. The equatorward boundary of the auroral oval reconstructed from the contemporary observational reports was as low as ≈28.5°/30.8° invariant latitude (ILAT; Hayakawa, Ebihara, Hand, et al, ). Note that ILAT signifies a parameter for the magnetic field line, along which electrons move and cause auroral brightening (Hayakawa, Ebihara, Hand, et al, ; O'Brien et al, ).…”

“…The auroral visibility around the Eurasian continent remains largely unexamined, except for the records in Western Europe and East Asia (e.g., Green & Boardsen, ; Hayakawa, Ebihara, Hand, et al, ; Kimball, ). Since the magnetic disturbances depend on magnetic local time, the simultaneous observations of the magnetic disturbances and the auroral visibilities provide a better understanding of the Carrington event.…”