contact: Hauke Schmidt
Most general circulation models of the middle atmosphere have their upper boundary in the 70-90 km region while “classical” models of the thermosphere/ionosphere mostly have their lower boundary near 80-95 km. HAMMONIA is one of the few models intended to overcome this separation. The model was developed at MPI-M, but with the contribution of scientists from other research institutions (V. Fomichev, York University, Canada; D. Kinnison, D. Marsh, S. Walters, NCAR). The model covers the atmospheric altitude range from the Earth's surface up to 1.7*10-7 hPa (about 250 km), which means not only tropo-, strato-, and mesosphere but also a considerable part of the thermosphere.
In the recent years HAMMONIA has been used for studies in a wide range of fields, covering the effects of solar variability and GHG increase, vertical coupling in the entire atmosphere, tidal activity, middle atmospheric wave activity in general, long-periodic oscillations in the mesosphere, the distribution of trace gases, etc. A list of publications where HAMMONIA simulations have been used is given at the bottom of this page.
A simple example for results obtained with HAMMONIA is given in the figure below. The left panel shows climatological zonal winds over the whole altitude range of the model domain with westerly winds in the winter strato- and mesosphere, easterlies at the same altitudes during summer, and a wind reversal around the mesopause. The right panel shows the same parameter obtained in a simulation with gravity waves switched off. The difference between the panels indicates the influence of small (sub-grid) scale gravity waves on the atmospheric circulation.
The following paragraph contains a brief description of the model. More details are given by Schmidt et al. (J. Climate, 2006). If you want to know more please contact Hauke Schmidt.
HAMMONIA consists of the vertical extension to the thermosphere of the MAECHAM5 model, which is itself an upward extension to the lower mesosphere of the ECHAM5 atmospheric GCM. HAMMONIA also comprises a full dynamic and radiative two-way coupling with the MOZART3 chemical module (Kinnison et al., JGR, 2007; 48 compounds, 148 gas phase reactions in the version used here). Ion chemistry is optional. HAMMONIA is a spectral model that has been run so far mainly in versions with triangular truncation at wavenumber 31 (T31) and with 67 or 119 vertical layers. The dynamical and radiative processes that have been specifically implemented for HAMMONIA include solar heating in the UV and EUV wavelength regime, a non-local thermodynamic equilibrium long-wave radiative scheme, heating and mixing due to parameterized gravity waves, vertical molecular diffusion and heat conduction, and parameterizations of electromagnetic forces in the thermosphere.