Simulation of denitrification and ozone loss for the Arctic winter 2002/2003

J.-U. Grooss (1) , G. Günther (1) , R. Müller (1) , P. Konopka (1) , S. Bausch (1) , H. Schlager (2) , C. Voigt (2) , C.M. Volk (3) , G. C. Toon (4)

1 ICG-1 - Institut für Chemie und Dynamik der Geosphäre - Stratosphäre
2 IPA - DLR Institut für Physik der Atmosphäre = DLR Institute of Atmospheric Physics
3 Institut für Meteorologie und Geophysik [Frankfurt]
4 JPL - Jet Propulsion Laboratory

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 HNO₃ downward flux resulting from different particle nucleation assumptions. The simulation results show a clear vertical redistribution of total inorganic nitrogen ( ), with a maximum vortex average permanent removal of over 5ppb in late December between 500 and 550K and a corresponding increase of of over 2ppb below about 450K. The simulated vertical redistribution of 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 7.8x10^-6cm^-3h^-1 in the model, the observed denitrification is well reproduced.

In the investigated winter 2002/2003, the denitrification has only moderate impact (?14%) on the simulated vortex average ozone loss of about 1.1ppm near the 460K level. At higher altitudes, above 600K potential temperature, the simulations show significant ozone depletion through -catalytic cycles due to the unusual early exposure of vortex air to sunlight.

Domaines: Océan, Atmosphère

J.-U. Grooss, G. Günther, R. Müller, P. Konopka, S. Bausch, et al.. Simulation of denitrification and ozone loss for the Arctic winter 2002/2003. Atmospheric Chemistry and Physics, 2005, 5 (6), pp.1437-1448. ⟨hal-00295667⟩