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

[摘要] We present simulations with the Chemical Lagrangian Model of theStratosphere (CLaMS) for the Arctic winter 2002/2003. We integrated aLagrangian denitrification scheme into the three-dimensionalversion of CLaMS that calculates the growth and sedimentation ofnitric acid trihydrate (NAT) particles along individual particletrajectories.From those, we derive the HNO₃ downward fluxresulting from different particle nucleation assumptions.The simulation results show a clear vertical redistribution of totalinorganic nitrogen ( ), with a maximum vortex average permanent removal of over 5ppb in late December between 500 and 550Kand a corresponding increase ofof over 2ppb below about450K.The simulated vertical redistribution ofis compared withballoon observations by MkIV and in-situ observations from the highaltitude aircraft Geophysica.Assuming a globally uniform NATparticle nucleation rate of 7.8x10^-6cm^-3h^-1 inthe model, the observed denitrification is well reproduced.In the investigated winter 2002/2003, the denitrification has onlymoderate impact (≤14%) on the simulated vortex average ozone loss ofabout 1.1ppm near the 460K level.At higher altitudes, above 600K potential temperature, the simulationsshow significant ozone depletion through -catalytic cycles due to theunusual early exposure of vortex air to sunlight.

[学科分类] 大气科学