Publication Abstracts

Field and Schmidt 2009

Field, C.V., and G.A. Schmidt, 2009: Model-based constraints on interpreting 20th century trends in ice core 10Be. J. Geophys. Res., 114, D12110, doi:10.1029/2008JD011217.

Beryllium-10 ice-core records are useful for understanding solar magnetic field changes over time, and in particular over the 20th century, during which there are variety of relevant observations. However, differences between 10Be snow concentration records from different locations complicate the process of developing a coherent understanding of changes in cosmogenic isotope production. We use the Goddard Institute for Space Studies ModelE general circulation model to simulate the production and transport of beryllium isotopes for this time period. We compare our results with surface air observations, and with ice-core records from Dye 3, Taylor Dome and South Pole. We find that unforced weather-related (internal) variability causes modeled trends in 10Be snow concentration to vary from the ensemble mean by 50% and greater at all three ice-core locations. Lower levels of internal variability at Taylor Dome and South Pole relative to Dye 3 make the simulated 10Be values at these locations better estimates of the ensemble-mean trend in 10Be snow concentration. In addition, the ensemble mean concentration trend at Dye 3 was significantly different from the expected modeled trend based on applied production changes alone. Overall, the results imply that during the 20th century, 10Be data from multiple cores are likely to be required to make meaningful inferences about 10Be production changes. The model simulations imply that data from Antarctica are likely to be more robust.