Evidence for climate modulation of the 10 Be solar activity proxy

• Published in: Journal of Geophysical Research
• Main Authors: Pedro, JB, van Ommen, TD, Curran, MAJ, Morgan, VI, Smith, A, McMorrow, AJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2006
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Antarctic; Austral; Law Dome; Antarc*; Antarctica; ice core
• Online Access: https://doi.org/10.1029/2005JD006764; http://ecite.utas.edu.au/42052

We used a snow pit record in conjunction with detailed snow accumulation data and oxygen isotope records to examine atmospheric transport and deposition effects on 10 Be at Law Dome, Antarctica. Data from an adjacent automatic weather station was used to date the record at snowfall event-scale resolution. In contrast to prior ice core studies in Antarctica, the snow pit record is of a sufficiently short duration (∼1 year) that 10 Be fluctuations reflect mainly atmospheric transport processes rather than solar modulation of production. Elevated concentrations of 10 Be were found in the late austral summer and early autumn snow, synchronous with the seasonal increase in stratospheric aerosols at Antarctic stations. A significant (P < 0.01) anticorrelation of 10 Be with δ 18 O occurs at the snowfall event scale. Fractionation of water isotopes at Law Dome is controlled by local and regional processes, specifically transport and local temperature. The anticorrelation seen here implies that 10 Be concentration was reduced in snow from warmer air masses (characterized by less negative δ 18 O). There is potential for confounding solar modulation with climatic modulation if at sites such as this one, warmer meteorological influences may be associated with reduced 10 Be concentrations. Quantification of the significance of this effect for the longer-term 10 Be record will require analysis of longer 10 Be records from different sites.