Atmospheric Chemistry and Physics Discussions
www.atmos-chem-phys-discuss.net
1680-7367
1680-7375
4
6
2004
10.5194/acpd-4-8069-2004
http://www.atmos-chem-phys-discuss.net/4/8069/2004/
http://www.atmos-chem-phys-discuss.net/4/8069/2004/acpd-4-8069-2004.html
http://www.atmos-chem-phys-discuss.net/4/8069/2004/acpd-4-8069-2004.pdf
8069
8101
2004-12-06
Simulation of denitrification and ozone loss for the Arctic winter 2002/2003
J.-U. Grooß
j.-u.grooss@fz-juelich.de
G. Günther
R. Müller
P. Konopka
S. Bausch
H. Schlager
C. Voigt
C. M. Volk
G. C. Toon
Institut für Chemie und Dynamik der Geosphäre I: Stratosphäre (ICG I), Forschungszentrum Jülich, Jülich, Germany
Institut für Physik der Atmosphäre, DLR Oberpfaffenhofen, Germany
Institut für Meteorologie und Geophysik, Universität Frankfurt, Germany
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
We present simulations with the Chemical Lagrangian Model of the
Stratosphere (CLaMS) for the Arctic winter 2002/2003. We integrated a
Lagrangian denitrification scheme into the three-dimensional
version of CLaMS that calculates the growth and sedimentation of
nitric acid trihydrate (NAT) particles along individual particle
trajectories. From those, we derive the HNO<sub>3</sub> downward flux
resulting from different particle nucleation assumptions.
The simulation results show a clear vertical redistribution of total
inorganic nitrogen (NO<sub>y</sub>), with a maximum vortex average permanent
NO<sub>y</sub> removal of over 5 ppb in late December between 500 and 550 K
and a corresponding increase of NO<sub>y</sub> of over 2 ppb below about
450 K.
The simulated vertical redistribution of NO<sub>y</sub> is compared with
balloon observations by MkIV and in-situ observations from the high
altitude aircraft Geophysica. Assuming a globally uniform NAT
particle nucleation rate of 3.4·10<sup>−6</sup>cm<sup>−3</sup>h<sup>−1</sup> in
the model, the observed denitrification is well reproduced.
<br><br>
In the investigated winter 2002/2003, the denitrification has only
moderate impact (≤10%) on the simulated vortex average ozone loss of
about 1.1 ppm near the 460 K level.
At higher altitudes, above 600 K potential temperature, the simulations
show significant ozone depletion through NO<sub>x</sub>-catalytic cycles due to the
unusual early exposure of vortex air to sunlight.