A 600-year annual 10Be record from the NGRIP ice core, Greenland

Despite the extensive use of Be-10 as the most significant information source on past solar activity, there has been only one record (Dye-3, Greenland) providing annual resolution over several centuries. Here we report a new annual resolution Be-10 record spanning the period 1389-1994 AD, measured in an ice core from the NGRIP site in Greenland. NGRIP and Dye-3 Be-10 exhibits similar long-term variability, although occasional short term differences between the two sites indicate that at least two high resolution Be-10 records are needed to assess local variations and to confidently reconstruct past solar activity. A comparison with sunspot and neutron records confirms that ice core Be-10 reflects solar Schwabe cycle variations, and continued Be-10 variability suggests cyclic solar activity throughout the Maunder and Sporer grand solar activity minima. Recent Be-10 values are low; however, they do not indicate unusually high recent solar activity compared to the last 600 years. Citation: Berggren, A.-M., J. Beer, G. Possnert, A. Aldahan, P. Kubik, M. Christl, S. J. Johnsen, J. Abreu, and B. M. Vinther (2009), A 600-year annual Be-10 record from the NGRIP ice core, Greenland, Geophys. Res. Lett., 36, L11801, doi: 10.1029/2009GL038004.