Washington, July 4 Scientists have analyzed Beryllium-10, a radioactive isotope, found from the NGRIP ice core, Greenland, which reflects solar activity over the past 600 years.

Beryllium-10, a radioactive isotope, 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.

Now, A.M. Berggren from the Department of Earth Sciences, Uppsala University, Uppsala, Sweden, and his colleagues have described 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, the researchers found that both show similar long-term trends with some short-term differences between the two sites.

The researchers also compared 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. (ANI)