Occurrence of Great Magnetic Storms on 6-8 March 1582. (arXiv:1905.08017v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Hattori_K/0/1/0/all/0/1">Kentaro Hattori</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hayakawa_H/0/1/0/all/0/1">Hisashi Hayakawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ebihara_Y/0/1/0/all/0/1">Yusuke Ebihara</a>
Although knowing the occurrence frequency of severe space weather events is
important for a modern society, it is insufficiently known due to the lack of
magnetic or sunspot observations, before the Carrington event in 1859 known as
one of the largest events during the last two centuries. Here, we show that a
severe magnetic storm occurred on 8 March 1582 based on auroral records in East
Asia. The equatorward boundary of auroral visibility reached 28.8{deg}
magnetic latitude. The equatorward boundary of the auroral oval is estimated to
be 33.0{deg} invariant latitude (ILAT), which is comparable to the storms on
25/26 September 1909 (~31.6{deg} ILAT, minimum Dst of -595 nT), 28/29 August
1859 (~36.5{deg} ILAT), and 13/14 March 1989 (~40{deg} ILAT, minimum Dst of
-589 nT). Assuming that the equatorward boundary is a proxy for the scale of
magnetic storms, we presume that the storm on March 1582 was severe. We also
found that the storm on March 1582 lasted, at least, for three days by
combining European records. The auroral oval stayed at mid-latitude for the
first two days and moved to low-latitude (in East Asia) for the last day. It is
plausible that the storm was caused by a series of ICMEs (interplanetary
coronal mass ejections). We can reasonably speculate that a first ICME could
have cleaned up interplanetary space to make the following ICMEs more
geo-effective, as probably occurred in the Carrington and Halloween storms.
Although knowing the occurrence frequency of severe space weather events is
important for a modern society, it is insufficiently known due to the lack of
magnetic or sunspot observations, before the Carrington event in 1859 known as
one of the largest events during the last two centuries. Here, we show that a
severe magnetic storm occurred on 8 March 1582 based on auroral records in East
Asia. The equatorward boundary of auroral visibility reached 28.8{deg}
magnetic latitude. The equatorward boundary of the auroral oval is estimated to
be 33.0{deg} invariant latitude (ILAT), which is comparable to the storms on
25/26 September 1909 (~31.6{deg} ILAT, minimum Dst of -595 nT), 28/29 August
1859 (~36.5{deg} ILAT), and 13/14 March 1989 (~40{deg} ILAT, minimum Dst of
-589 nT). Assuming that the equatorward boundary is a proxy for the scale of
magnetic storms, we presume that the storm on March 1582 was severe. We also
found that the storm on March 1582 lasted, at least, for three days by
combining European records. The auroral oval stayed at mid-latitude for the
first two days and moved to low-latitude (in East Asia) for the last day. It is
plausible that the storm was caused by a series of ICMEs (interplanetary
coronal mass ejections). We can reasonably speculate that a first ICME could
have cleaned up interplanetary space to make the following ICMEs more
geo-effective, as probably occurred in the Carrington and Halloween storms.
http://arxiv.org/icons/sfx.gif
