Meridional transport and deposition of atmospheric 10Be U. Heikkilä1, J. Beer1, and J. Feichter2 1EAWAG, Überlandstrasse 133, 8600 Dübendorf, Switzerland 2Max-Planck Institute for Meteorology, Hamburg, Germany
Abstract.10Be concentrations measured in ice cores exhibit larger temporal
variability than expected based on theoretical production calculations.
To investigate whether this is due to atmospheric transport a general
circulation model study is performed with the 10Be production divided
into stratospheric, tropospheric tropical, tropospheric subtropical and
tropospheric polar sources. A control run with present day 10Be
production rate is compared with a run during a geomagnetic minimum.
The present 10Be production rate is 4–5 times higher at high latitudes
than in the tropics whereas during a period of no geomagnetic dipole field
it is constant at all latitudes. The 10Be deposition fluxes, however,
show a very similar latitudinal distribution in both the present day and
the geomagnetic minimum run indicating that 10Be is well mixed in the
atmosphere before its deposition. This is also confirmed by the fact that
the contribution of 10Be produced in the stratosphere is dominant
(55%–70%) and relatively constant at all latitudes. The contribution of
stratospheric 10Be is approximately 70% in Greenland and 60% in
Antarctica reflecting the weaker stratosphere-troposphere air exchange
in the Southern Hemisphere.
Citation: Heikkilä, U., Beer, J., and Feichter, J.: Meridional transport and deposition of atmospheric 10Be, Atmos. Chem. Phys., 9, 515-527, doi:10.5194/acp-9-515-2009, 2009.