Model‐based constraints on interpreting 20th century trends in ice core ¹⁰Be

Abstract

[1] 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 a variety of relevant observations. However, differences between 10 Be 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 10

Volcanic and solar activity, and atmospheric circulation influences on cosmogenic 10Be fallout at Vostok and Concordia (Antarctica) over the last 60years

“…The meteorological noise also contributes to the 10 Be signal at Law Dome for example (Pedro et al, 2006). Modeling studies also highlight the importance of non-solar parameters that influence the 10 Be signal recovered from snow/ice (Field et al, 2006;Field and Schmidt, 2009). A comparison of 14 C and 10 Be data over the last millennium showed that the coherence between 14 C-based production signals and any 10 Be data is better at the short time scale (<100 yr) than between different 10 Be series, indicating that the climatic signal plays an essential role in 10 Be at short time scale .…”

“…Webber et al (2010) noted the overall attenuation of the snow signal with respect to calculated global and 10 Be polar production (>65°of latitude). Imprecision may also arise when considering 10 Be production related only to the snow depositional flux, while dry and wet deposition may occur in variable proportions (Field et al, 2006;Pedro et al, 2006;Field and Schmidt, 2009).…”

Production rate and climate influences on the variability of 10Be deposition simulated by ECHAM5‐HAM: Globally, in Greenland, and in Antarctica

“…To our knowledge, this is the first climatological type of investigation concentrating on connections between atmospheric and 10 Be variability. Previous efforts to simulate the atmospheric transport and deposition using the GISS‐ModelE [ Field et al ] and ECHAM5‐HAM [ Heikkilä et al , , ; ] have investigated an atmospheric mean state only or the 21st century climate, trends, and grand solar minima [ Field and Schmidt , ].…”

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

“…From a modeling perspective, simulation of 10 Be requires a three‐dimensional model of the atmosphere, coupled with an aerosol module describing the production, transport and deposition processes of atmospheric particles. Both the GISS ModelE [ Schmidt et al , 2006] and the ECHAM5‐HAM GCMs [ Roeckner , 2003] have been used to simulate 10 Be deposition to the ice sheets [ Heikkilä et al , 2008c, 2009; Field et al , 2006, 2009; Field and Schmidt , 2009]. To date, because of the lack of highly resolved records, it has not been possible to test GCM performance against seasonal variations in 10 Be concentrations in Antarctic ice.…”