Climate and Production-Related Impacts on Beryllium-10

Christy Field [cfield@giss.nasa.gov], Columbia University, DEES, New York and NASA Goddard Institute for Space Studies; Gavin Schmidt and Dorothy Koch, NASA Goddard Institute for Space Studies and Center for Climate Systems Research, Columbia University, New York; and Colette Salyk, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena.

            The connection between the production of the cosmogenic isotope 10Be and changes in heliomagnetic activity makes ice-core 10Be an attractive proxy for studying changes in solaroutput. However, interpreting 10Be ice core recordson centennial timescales is complicated by potentialclimate-related deposition changes that could obscure the 10Be production signal. By using the Goddard Institute for Space Studies ModelE general circulation model to selectively varyclimate and production functions, we model 10Be fluxat key ice-coring sites. We investigate the changes inlatitudinal 10Be fluxes as a function of geomagnetic and solarproduction changes. In our climate experiments,the 10Be deposition changes simulated over ice sheets in bothhemispheres are comparable to those seen in the productionexperiments. This altered deposition combined with climate-relatedimpacts on accumulation results in significant 10Be snowconcentration variation over both Greenland and Antarctica. Over the Holocene, our results suggest that the 10Be response to climatechange can be of the same order of magnitude as the response to solarchanges, though generally smaller. This finding suggests climate'spotential role in amplifying production-related 10Be changes andunderscores the importance of considering climate effects when attempting to infer solar variability from 10Be records.