Cl-36 bomb peak: Comparison of modeled and measured data ...

• Main Authors: Heikkilä, Ulla, Beer, Jürg, Feichter, Johann, Alfimov, Vasily, Synal, Hans-Arno, Schotterer, Ulrich, Eichler, Anja, Schwikowski, Margit, Thompson, Lonnie
• Format: Article in Journal/Newspaper
• Language: English
• Published: ETH Zurich 2009
• Subjects: Antarc*; Antarctica; Berkner Island; Greenland; GRIP
• Online Access: https://dx.doi.org/10.3929/ethz-b-000022094; http://hdl.handle.net/20.500.11850/22094

The extensive nuclear bomb testing of the fifties and sixties and the final tests in the seventies caused a strong 36Cl peak that has been observed in ice cores world-wide. The measured 36Cl deposition fluxes in eight ice cores (Dye3, Fiescherhorn, Grenzgletscher, Guliya, Huascarán, North GRIP, Inylchek (Tien Shan) and Berkner Island) were compared with an ECHAM5-HAM general circulation model simulation (1952–1972). We find a good agreement between the measured and the modeled 36Cl fluxes assuming that the bomb test produced global 36Cl input was ~80 kg. The model simulation indicates that the fallout of the bomb test produced 36Cl is largest in the subtropics and mid-latitudes due to the strong stratosphere-troposphere exchange. In Greenland the 36Cl bomb signal is quite large due to the relatively high precipitation rate. In Antarctica the 36Cl bomb peak is small but is visible even in the driest areas. The model suggests that the large bomb tests in the Northern Hemisphere are visible around the globe but ... : Atmospheric Chemistry and Physics, 9 (12) ...