The ECHAM model is run at a spectral resolution of T127L95, where T127
denotes a spectral truncation at total wavenumber 127, which corresponds
to about 100 km horizontal resolution in the tropics and higher
horizontal (zonal) resolution towards the poles - for example about 25
km in 75° latitude. L95 stands for 95 unevenly spaced model levels with
high vertical resolution close to the surface (60 to 300 m in the
atmospheric boundary layer) and reaching up to 0.01 hPa corresponding to
80 km (i.e. high-top model version).
In our AWI-CM-1-1-MR CMIP6 contribution (Semmler et al. 2018), the FESOM
model is run on a medium-resolution ”MR” mesh that follows the mesh
design strategy proposed by Sein et al. (2016, 2017) (Fig. 1): The main
approach is to locally increase the resolution over areas of high sea
surface height (SSH) variability as obtained from satellite data. The
horizontal resolution of the mesh varies from 8 km over energetically
active areas such as the North Atlantic Current region to 80 km over
areas with low SSH variability. The number of surface grid points of the
MR mesh is close to the number of grid points in conventional regular
model grids of ¼° resolution. The performance of the “MR-type” meshes
in a climate configuration with AWI-CM in comparison to several other
FESOM meshes is evaluated in de la Vara et al. (2020), Rackow et al.
(2019), Sein et al. (2018).