Solar Activity of the Past 100 Years Inferred From 10Be in Ice Cores—Implications for Long‐Term Solar Activity Reconstructions. Issue 4 (16th February 2021)

• Record Type: Journal Article
• Authors: Zheng, Minjie; Adolphi, Florian; Sjolte, Jesper; Aldahan, Ala; Possnert, Göran; Wu, Mousong; Chen, Peng; Muscheler, Raimund
• Is Part Of: Geophysical research letters. Volume 48:Issue 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-02-16
• Subjects: Dye3 -- ice core -- NEEM -- neutron monitor data -- seasonally resolved 10Be -- solar reconstructions; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL090896
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Differences between 10 Be records from Greenland and Antarctica over the last 100 years have led to different conclusions about past changes in solar activity. The reasons for this disagreement remain unresolved. We analyze a seasonally resolved 10 Be record from a firn core (North Greenland Eemian Ice Drilling [NEEM] ice core project) in Northwestern Greenland for 1887–2002. By comparing the NEEM data to 10 Be data from the NGRIP and Dye3 ice cores, we find that the Dye3 data after 1958 are significantly lower. These low values lead to a normalization problem in solar reconstructions when connecting 10 Be variations to modern observations. Excluding these data strongly reduces the differences between solar reconstructions over the last 2, 000 years based on Greenland and Antarctic 10 Be data. Furthermore, 10 Be records from polar regions and group sunspot numbers do not support a substantial increase in solar activity for the 1937–1950 period as proposed by previous extensions of the neutron monitor data. Key Points: Summer NEEM 10 Be concentrations are generally higher than winter 10 Be concentrations due to the stratospheric intrusion Erroneous Dye 3 10 Be data can bias solar activity estimates for the past toward too low 10 Be and sunspot data suggest higher solar activity than extensions of the neutron monitor data before 1951