Draft:Medieval maximum

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[[File:Carbon14_with_activity_labels.svg|thumb|309x309px|Solar activity events recorded in radiocarbon. Values since 1950 not shown.]]
The '''Medieval maximum''' is a [[solar maximum]] event that occurred between the years 1100-1250, which also corresponded with the [[Medieval Warm Period]]. [[Paleoclimatology|Paleoclimate studies]] identified this period through the usage of surviving [[Dendrochronology|dendrochronological]] records as well as [[radiocarbon dating]] in addition to other isotopes such as [[Beryllium-10]] to measure [[Cosmogenic isotope|cosmogenic]] isotope production by solar rays.{{Cite journal |last=Jirikowic |first=J. L. |last2=Damon |first2=P. E. |date=1994-03-01 |title=The medieval solar activity maximum |url=https://doi.org/10.1007/BF01092421 |journal=Climatic Change |language=en |volume=26 |issue=2 |pages=309–316 |doi=10.1007/BF01092421 |issn=1573-1480}}{{Cite web |last=Krywko |first=Jacek |title=Medieval poets wrote about auroras. Their work is providing clues to the solar cycle |url=https://www.scientificamerican.com/article/medieval-aurora-poetry-provided-clues-to-historic-solar-storms/ |access-date=2026-04-25 |website=Scientific American |language=en}} This correspondence of the solar activity during this activity presented the trend of increased agricultural activity in Europe, expanded urbanization, and warmer sea temperatures in [[Japan]], and with it, [[solar phenomena]] has been documented through the contemporary records in [[China]], Japan, and [[Goryeo kingdom|Goryeo Korea]].{{Cite journal |last=MIYAHARA |first=Hiroko |last2=KATAOKA |first2=Ryuho |last3=YAMAMOTO |first3=Kazuaki |last4=TOKANAI |first4=Fuyuki |last5=MORIYA |first5=Toru |last6=TAKEYAMA |first6=Mirei |last7=SAKURAI |first7=Hirohisa |last8=OHYAMA |first8=Motonari |last9=HORIUCHI |first9=Kazuho |last10=HOTTA |first10=Hideyuki |date=2026-04-10 |title=Extremely active Sun from 1190 to 1220 in the Medieval Period: Intercomparison of historical records and tree-ring carbon-14 |url=https://doi.org/10.2183/pjab.102.011 |journal=Proceedings of the Japan Academy, Series B |volume=102 |issue=4 |pages=156–166 |doi=10.2183/pjab.102.011 |issn=0386-2208}}{{Cite web |title=Geologic Evidence of Recurring Climate Cycles and Their Implications for the Cause of Global Climate Changes—The Past is the Key to the Future |url=https://www.sciencedirect.com/science/chapter/monograph/abs/pii/B9780123859563100014 |access-date=2026-04-25 |website=www.sciencedirect.com |language=en-US |doi=10.1016/B978-0-12-385956-3.10001-4}}

== Solar Phenomena Observations ==
{| class="wikitable"
! colspan="3" |'''Solar activity events and approximate dates'''
|-
!Event
!Start
!End
|-
|[[Homeric Minimum]]{{Cite journal |last=Ineson |first=Sarah |last2=Maycock |first2=Amanda C. |last3=Gray |first3=Lesley J. |last4=Scaife |first4=Adam A. |last5=Dunstone |first5=Nick J. |last6=Harder |first6=Jerald W. |last7=Knight |first7=Jeff R. |last8=Lockwood |first8=Mike |last9=Manners |first9=James C. |last10=Wood |first10=Richard A. |date=2015-06-23 |title=Regional climate impacts of a possible future grand solar minimum |url=https://www.nature.com/articles/ncomms8535 |journal=Nature Communications |language=en |volume=6 |issue=1 |pages=7535 |doi=10.1038/ncomms8535 |issn=2041-1723}}
|800 BC
|600 BC
|-
|Oort minimum {{cite web |title=History of Sunspot Observations |url=http://www.windows.ucar.edu/tour/link=/sun/activity/sunspot_history.html&edu=high |accessdate=4 February 2009}} The Spörer Minimum (1420 to 1570), named after the German astronomer Gustav Spörer.
|1010
|1050
|-
|Oort minimum
|1040
|1080
|-
|'''Medieval maximum'''
|1100
|1250
|-
|Wolf minimum
|1280
|1350
|-
|Spörer Minimum
|1460
|1550
|-
|[[Maunder Minimum]]
|1645
|1715
|-
|[[Dalton Minimum]]
|1790
|1830
|-
|[[Modern Maximum]]
|1950
|2009
|}
Observations of solar activity, prominently [[Aurora|auroras]] are prominent when charged particles from the [[Sun]] reach [[Earth]] and interact with the [[Earth's magnetic field|magnetic field]], generating light.{{Cite web |date=2025-02-04 |title=Auroras - NASA Science |url=https://science.nasa.gov/sun/auroras/ |access-date=2026-04-25 |language=en-US}} In periods of high solar activity, those auroras can reach down to the low latitudes of Japan and Southern China.{{Cite journal |last=Kataoka |first=Ryuho |last2=Isobe |first2=Hiroaki |last3=Hayakawa |first3=Hisashi |last4=Tamazawa |first4=Harufumi |last5=Kawamura |first5=Akito Davis |last6=Miyahara |first6=Hiroko |last7=Iwahashi |first7=Kiyomi |last8=Yamamoto |first8=Kazuaki |last9=Takei |first9=Masako |last10=Terashima |first10=Tsuneyo |last11=Suzuki |first11=Hidehiko |last12=Fujiwara |first12=Yasunori |last13=Nakamura |first13=Takuji |date=28 January 2017 |title=Historical space weather monitoring of prolonged aurora activities in Japan and in China |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2016SW001493 |journal=Advancing Earth and Space Sciences: Space Weather |language=en |volume=15 |issue=2 |pages=392–402 |doi=10.1002/2016SW001493 |issn=1542-7390}} Such unusual solar activity were observed by contemporary historians at the time and in many instances during the [[1st millennium|first millennia]], many such instances were documented in as part of the annals of China's [[Twenty-Four Histories]], with the oldest references to phenomena going as far back as the 10th century BC in the [[Bamboo Annals]].{{Cite journal |last=van der Sluijs |first=Marinus Anthony |last2=Hayakawa |first2=Hisashi |date=2023-12-15 |title=A candidate auroral report in the Bamboo Annals, indicating a possible extreme space weather event in the early 10th century BCE |url=https://www.sciencedirect.com/science/article/pii/S0273117722000229 |journal=Advances in Space Research |series=COSPAR Space Weather Roadmap 2022-2024: Scientific Research and Applications |volume=72 |issue=12 |pages=5767–5776 |doi=10.1016/j.asr.2022.01.010 |issn=0273-1177}}

During the medieval period, physical descriptors of the solar activity were frequently described in [[Old History of the Five Dynasties]] (舊五代史) as well as the [[Book of Song]].''''

''On 14 Feb. 937, at night, red and white vapors appeared alternately, like a cultivated and exploited bamboo forest, from 23:00 to 3:00, muddily from north to the middle in the sky, flickering unstably went around the 28 lunar mansions and disappeared at the dawn.'' ''- [[Old History of the Five Dynasties]] ''

One of the most prominent solar maximum activity documented in Japan, was during the [[Kamakura period]] in 21-24 February 1204 with multiple sightings in [[Heian-kyō|Kyoto]]. Two prominent observers include the poet [[Fujiwara no Teika]], who recorded the activity in his diary the [[Meigetsuki (Diary)|''Meigetsuki'']] and the author of the historical chronicle, the ''Omuro Soshoki'' (now housed in [[Ninna-ji]] and is a [[National Treasure (Japan)|National Treasure]]).''''

''On 1204/02/21, it was sunny. … After sunset, red vapor appeared in the direction of north and north-east. The lower part of red vapor was shaped like a rising moon and colored white and bright. Its stripes extended faraway and was like smokes in fires. There were four or five of white parts and three or four of red vapors appeared. Is it neither cloud nor stands within clouds? Its light did not get darken and red light is mixed in the white light. It is nothing but a mystery. It is also very dreadful.'' ''On 1204/02/23, it was sunny and quite windy. … In the time when to put a fire on the lamp, red vapor appeared in the north and north-east. It was like a distant mountain burning. It was very dreadful.'' ''- '''Meigetuski'''''

''On 1204/02/21, at 20:00, red vapor appeared with white cloud mixed and was seen from north-west to north-east. On 1204/02/22 as well. On 1204/02/23, as well. Takashige stated that these were very rare disaster. We put off the pilgrimage to Koyasan.'' ''- '''Omuro Soshoki'''''

In the ''Book of Song,'' 21 February 1204 aurora activity also coincided with visible descriptions of the sun itself, describing a "black spot as big as a [[jujube]]".''''''''''

As the oldest extreme space weather ever documented in those three days, it can be inferred that the frequency of activity in East Asia was attributed towards the [[Geomagnetic pole|geomagnetic pole's]] lean to the region, and the strength of the storms were accompanied by medieval French and German chronicles at the time.

== Radiocarbon Dating ==
[[Cosmic ray|Cosmic Radiation]] often leads to a giant spike of [[Carbon-14]] within the [[Dendrochronology|dendrochronological records]] and has been recorded in large doses within wood samples dating to the 8th century, which could be detected with [[Accelerated mass spectrometer|accelerated mass spectrometry]], though the corresponding 13th century records could not be detected in that matter.{{Cite journal |last=Miyahara |first=Hiroko |last2=Tokanai |first2=Fuyuki |last3=Moriya |first3=Toru |last4=Takeyama |first4=Mirei |last5=Sakurai |first5=Hirohisa |last6=Ohyama |first6=Motonari |last7=Horiuchi |first7=Kazuho |last8=Hotta |first8=Hideyuki |date=21 February 2022 |title=Recurrent Large‐Scale Solar Proton Events Before the Onset of the Wolf Grand Solar Minimum |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097201 |journal=Geophysical Research Letters |language=en |volume=49 |issue=5 |doi=10.1029/2021GL097201 |issn=0094-8276 |archive-url=http://web.archive.org/web/20250405075014/https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL097201 |archive-date=2025-04-05}}

The study of the [[Meigetsuki (Diary)|''Meigetsuki'']] was cross-matched with the analysis of ''[[Cryptomeria japonica]]'' (asunaro) trees excavated from [[Shimokita Peninsula]], [[Aomori Prefecture]], where each tree-ring was separated with the [[cellulose]] extracted and convered into [[graphite]] to allow for the actual breakdown of carbon-14 levels throughout the 13th century.

It was determined that although the levels of carbon-14 were not particularly high when Fujiwara no Teika recorded his observations, it was a few years prior in 1200-1201 that a [[Solar proton event|solar proton]] event registered with the trees and that it was 14-times larger than the landmark [[20th century]] solar storm of 23 February 1956.{{Cite journal |last=Rishbeth |first=H. |last2=Shea |first2=M. A. |last3=Smart |first3=D. F. |date=2009-11-16 |title=The solar-terrestrial event of 23 February 1956 |url=https://www.sciencedirect.com/science/article/pii/S0273117709004761 |journal=Advances in Space Research |series=Cosmic Rays From Past to Present |volume=44 |issue=10 |pages=1096–1106 |doi=10.1016/j.asr.2009.06.020 |issn=0273-1177}}

Additional solar flare activity within the asunaro tree-rings detected spikes of radiation in 1261/1262, 1268/1269, and 1279/1280, each spike weakening and eventually giving way to the [[Wolf minimum]].

== References ==

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