Summary
Modelled 10Be production by solar cosmic ray (SCR) events is compared with measured 10Be concentrations in a Law Dome snow pit record. The snow pit record spans 2.7 years, providing a quasi-monthly 10Be sampling resolution which overlaps with the SCR events of 29 Oct 2003 and 20 Jan 2005. These events were calculated to increase monthly 10Be production in the polar atmosphere (> 65¢ª S geomagnetic latitude) by ~60% and ~120% above the background, respectively. A strong peak in 10Be concentrations (> 4¥ò above the 2.7 yr mean value) was observed ~1 month after the 20 Jan 2005 event. By contrast, no signal in 10Be concentrations was observed following the weaker 29 Oct 2003 series of events. The concentration of 10Be in ice core records involves interplay between production, transport and deposition processes. We used a particle dispersion model to assess vertical and meridional transport of aerosols from the lower stratosphere where SCR production of 10Be is expected to occur, to the troposphere from where deposition to the ice sheet occurs. Model results suggested that a coherent SCR production signal could be transported to the troposphere within weeks to months following both SCR events. We show that only the 20 Jan 2005 SCR event was observed in measured concentrations due to favourable atmospheric transport and relatively high production yield compared to the 29 Oct 2003 event.