Ozone Climatology

An idealised distribution of ozone has been constructed for APE, based on the AMIP II climatology by Liang and Wang.   The APE distribution consists of the annual mean AMIP II distribution, zonally averaged and symmetrized about the equator.  

Location:
The formatted data can be downloaded here.   A Fortran subroutine to read the data is here.

Use in APE:
The data are provided on a latitude-pressure grid.   The pressure levels correspond to layer centres and the latitudes correspond to a quadratic gaussian grid for T42 spectral truncation.   Liang and Wang provided documentation on the creation and implementation of their ozone climatology.

Documentation:
The data were created by annually averaging the monthly AMIP II ozone climatology, accounting for variable month length, then symmetrizing about the equator.   This ensures symmetric absorption of solar radiation, so that the sole asymmetric forcing in the APE experimental suite is due to the asymmetry of one of the imposed SST distributions.

Fig.1 shows the annual mean AMIP II climatology and Fig.2 the symmetrized version for APE.   For comparison, Fig.3 shows the AMIP II climatology for March, which contains significant asymmetries.   In the mid-latitude lower stratosphere in March, the northern hemisphere has higher ozone concentration than the corresponding southern hemispheric location.   If used for APE, this would lead to increased solar heating and possibly a more closed jet structure above the northern hemisphere mid-latitude tropopause.