Solar Activity of the Past 100 Years Inferred From ¹⁰Be in Ice Cores—Implications for Long-Term Solar Activity Reconstructions

Summary, in English

Differences between ¹⁰Be 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 ¹⁰Be 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 ¹⁰Be 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 ¹⁰Be 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 ¹⁰Be data. Furthermore, ¹⁰Be 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.

• Author: Minjie Zheng; Florian Adolphi; Jesper Sjolte; Ala Aldahan; Göran Possnert; Mousong Wu; Peng Chen; Raimund Muscheler
• Department/s: Quaternary Sciences; MERGE: ModElling the Regional and Global Earth system
• Publishing year: 2021-02
• Language: English
• Publication/Series: Geophysical Research Letters
• Volume: 48
• Issue: 4
• Links: http://dx.doi.org/10.1029/2020GL090896
• Document type: Journal article (letter)
• Publisher: American Geophysical Union (AGU)
• Topic: Earth and Related Environmental Sciences
• Keywords: Dye3; ice core; NEEM; neutron monitor data; seasonally resolved Be; solar reconstructions
• Status: Published
• ISBN/ISSN/Other: ISSN: 0094-8276