The Dalton Minimum was a period of low

sunspot Sunspots are phenomena on the Sun's photosphere that appear as temporary spots that are darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic flux that inhibit convection. Sun ...

count, representing low

solar activity Solar phenomena are natural phenomena which occur within the atmosphere of the Sun. These phenomena take many forms, including solar wind, radio wave flux, solar flares, coronal mass ejections, coronal heating and sunspots. These phenomena are ...

, named after the English meteorologist

John Dalton John Dalton (; 5 or 6 September 1766 – 27 July 1844) was an English chemist, physicist and meteorologist. He is best known for introducing the atomic theory into chemistry, and for his research into colour blindness, which he had. Colour b ...

, lasting from about 1790 to 1830 or 1796 to 1820, corresponding to the period solar cycle 4 to solar cycle 7. While the Dalton Minimum is often compared with the Maunder Minimum, its sunspot number was slightly higher and reported sunspots distributed in both solar hemispheres unlike the Maunder Minimum. The coronal streamers are visually confirmed in

Ezra Ames Ezra Ames (May 5, 1768 – February 23, 1836) was a popular portrait painter in Albany, New York, during the late 18th and early 19th centuries. More than 700 portraits have been attributed to him. Life and career He was born in Framingham, Mas ...

and José Joaquin de Ferrer’s eclipse drawings in 1806 and indicates similarity of its magnetic field not with that of the Maunder Minimum but with that of the modern solar cycles.

Temperature

Like the Maunder Minimum and

Spörer Minimum The Spörer Minimum is a hypothesized 90-year span of low solar activity, from about 1460 until 1550, which was identified and named by John A. Eddy in a landmark 1976 paper published in ''Science (journal), Science'' titled ''Maunder minimum, "The ...

, the Dalton Minimum coincided with a period of lower-than-average global temperatures. During that period, there was a variation of temperature of about 1 °C in Germany. The cause of the lower-than-average temperatures and their possible relation to the low sunspot count are not well understood. Recent papers have suggested that a rise in

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...

was largely responsible for the cooling trend. While the

Year Without a Summer The year 1816 is known as the Year Without a Summer because of severe climate abnormalities that caused average global temperatures to decrease by . Summer temperatures in Europe were the extreme weather, coldest on record between the years of 1 ...

, in 1816, occurred during the Dalton Minimum, the prime reason for that year's cool temperatures was the highly explosive eruption the previous year of

Mount Tambora Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active subduction zones beneath it. Before 1815, its elevation reached more than ...

in Indonesia, which was one of the two largest eruptions in the past 2000 years. One must also consider that the rise in volcanism may have been triggered by lower levels of solar output as there is a weak but statistically significant link between decreased solar output and an increase in volcanism.

Notes

References

*Hayakawa, Hisashi et al. (2020a)
Thaddäus Derfflinger's Sunspot Observations during 1802–1824: A Primary Reference to Understand the Dalton Minimum"
in ''The Astrophysical Journal'', 890, 98. *Hayakawa, Hisashi et al. (2020b)
"The Solar Corona during the Total Eclipse on 1806 June 16: Graphical Evidence of the Coronal Structure during the Dalton Minimum"
in ''The Astrophysical Journal'', 900, 114. *Komitov, Boris and Vladimir Kaftan (2004)
The Sunspot Activity in the Last Two Millennia on the Basis of Indirect and Instrumental Indexes: Time Series Models and Their Extrapolations for the 21st Century"
in ''Proceedings of the International Astronomical Union'', 2004, pp. 113–114. *Wagner, Sebastian and

Eduardo Zorita Eduardo Zorita (born 1961 in Madrid) is a Spanish paleoclimatologist. , he is a Senior Scientist at the Institute for Coastal Research, GKSS Research Centre in Geesthacht, Germany, where he has worked since 1996. Zorita is review editor of the j ...

(2005)
The influence of volcanic, solar and CO2 forcing on the temperatures in the Dalton Minimum (1790–1830): a model study
, ''Climate Dynamics'' v. 25, pp. 205–218, doi 10.1007/s00382-005-0029-0. *Wilson, Robert M. (nd)
Volcanism, Cold Temperature, and Paucity of Sunspot Observing Days (1818–1858): A Connection?
, The Smithsonian/NASA Astrophysics Data System, accessed February 2009. 1790s 19th century History of climate variability and change Solar phenomena {{sun-stub

Temperature

See also

Notes

References