HEPPA-I

Observations

MIPAS/ENVISAT L2 data generated at IMK and IAA have been used. Among the species affected by SPEs we focused on NO, NO2, N2O, N2O5, HNO3, HNO4, H2O2, O3, ClO, HOCl, and ClONO2. Further, the meteorological conditions in both the models and the real atmosphere as observed by MIPAS have been assessed by comparing temperature and tracer fields (CH4 and CO).

 

Participating models

B2dM, B3dCTM, CAO, EMAC, FinROSE, HAMMONIA, KASIMA, SOCOL(i), and WACCM.

 

Results

  • State-of-the art atmospheric models do a very good job in reproducing observed SPE-induced ozone depletion (within 5% on both short- and mid-term scales) and NOy enhancements (except region around 1 hPa).
  • Possible reasons for remaining differences have been identified (see Funke et al., 2011)
  • Differences in meteorology and/or initial state of the atmosphere in the simulations cause important dispersion of the model responses to the SPE.
  • SPE-induced changes of new species (H2O2, HNO4, and CO) have been identified.

‚Äč

The left panel shows MIPAS measurements of SPE-related ozone changes (bold dashed line) in comparison with numerous model simulations. The bold solid line represents the multi-model mean. The right panel is the same for NOy changes.

[back to Case Studies]