S. Chabrillat
Evaluation of different analyses with a single CTM:
challenges and benefits
The formulation of the underlying AGCM is very important to
determine the coupling strategy with the CTM. The BASCOE CTM was
originally developed to be driven by analyses from ECMWF, i.e.
computed by the spectral model IFS. The coupling in this case is
optimal thanks to an algorithm developed at KNMI (Bregman et al.,
ACP, 2003) which derives mass-conserving fluxes from vorticity and
divergence in spectral space. The BASCOE CTM has been adapted to
also accept analyses from the Canadian meteorological Center, i.e.
from the grid-based model GEM. We will use long-lived stratospheric
tracers to show the different transport characteristics in each
case, and discuss the challenges and benefits in using a single CTM
to evaluate completely different analyses.
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