AGU: Geophysical Research Letters

 

Editors' Highlight

Beryllium-10 ice core record traces solar activity over 600 years

Climate scientists and solar physicists have increasingly been using beryllium-10 levels to gain information about past solar activity. Beryllium-10 is produced in cosmic ray showers. Because stronger solar activity deflects cosmic rays away from Earth, low levels of beryllium-10 correlate with higher solar activity. However, few extensive beryllium-10 records exist. Berggren et al. (2009) describe a new 600-year beryllium-10 record from the North Greenland Ice Core Project (NGRIP), one of only two beryllium-10 records with annual resolution over several centuries. Comparing the NGRIP record with the Dye-3 record from another site in Greenland, they find that both show similar long-term trends with some short-term differences between the two sites. The authors also compare the NGRIP and Dye-3 data with sunspot records and with neutron data, which tracks cosmic ray intensity. Their results confirm that ice core beryllium-10 reflects solar cycle variations as well as longer-term trends in solar activity. They note that while recent beryllium-10 values are low, they do not indicate unusually high solar activity compared with the last 600 years.

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