HEPPA-II

Observations

Spatially resolved observational data during November 2008 – May 2009 are available from a large number of instruments (e.g., ACE-FTS; GOMOS, MIPAS, and SCIAMACHY on Envisat; MLS/Aura; SMR/Odin; SABER/TIMED), including NO and temperature up to the middle thermosphere, O3 and CO up to 100 km, as well as stratospheric and mesospheric distributions of NO2, HNO3, N2O5, N2O, and CH4.

 

Participating models

B3dCTM, CAO, CMAM, EMAC, FinROSE, HAMMONIA, KASIMA, MRI, SOCOL, and WACCM.

 

Expected Results

  • Validation of EPP implementations in atmospheric models
  • A better understanding of the EPP source distribution and vertical coupling mechanisms
  • Quantification (and model validation) of EPP indirect effects on stratospheric chemistry.

 

‚Äč

The figure shows the temporal evolution of NOx (top) and CO (bottom) from MIPAS averaged over 60-90N. Until January 2009, the winter was characterized by homogeneous descent with minor perturbations. The major warming around 20 January led to CO and NOx depletion in the USM (40-70 km) related to the weakening of the vortex. Pronounced descent and entrainment of NOx occurred in Feb-March within an unusually strong re-established vortex.

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