Beryllium-10 transport to Antarctica: Results from seasonally resolved observations and modeling

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Pedro, JB, Heikkila, UE, Klekociuk, A, Smith, AM, van Ommen, TD, Curran, MAJ
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2011
• Subjects: Earth Sciences; Physical Geography and Environmental Geoscience; Glaciology; Antarctic; Austral; East Antarctica; Greenland; Law Dome; Neumayer; The Antarctic; Antarc*; Antarctica; ice core
• Online Access: https://doi.org/10.1029/2011JD016530; http://ecite.utas.edu.au/76821

Cosmogenic 10Be measured in polar ice cores has important application in the reconstruction of past solar activity. However, the processes controlling its atmospheric transport and deposition to the ice sheets are not fully understood. Here we use the seasonal changes in 10Be concentrations in a 10 year monthly resolved ice core record from the Law Dome site (East Antarctica) in conjunction with ECHAM5-HAM general circulation model (GCM) simulations of 10Be and 7Be deposition as tools to examine this problem. Maximum 10Be concentrations are observed in the ice core during the austral late summer to early autumn (summer-autumn), while minimum concentrations are observed during the austral winter. The GCM simulations, corroborated by earlier observations of 10Be:7Be ratios in Antarctica from the Georg von Neumayer air sampling station, suggest that the 10Be concentration maximum is linked to direct input of stratospheric 10Be from the Antarctic stratosphere to the lower levels of the Antarctic troposphere during the austral summer-autumn. This result contrasts with the modeled transport of 10Be to Greenland, where the seasonal maximum in stratospheric input is seen in the late winter to spring, synchronous with the timing of the seasonal maximum in midlatitude stratosphere to troposphere exchange. Our results suggest that a different combination of processes is responsible for the transport of 10Be to the Antarctic and Greenland ice sheets.