Zonal Mean Diagnostics of the Transport Properties of GCMs and DASs

The chemistry transport models (CTMs) aim to reproduce the observed distributions of the long-lived and short-lived species in the troposphere and stratosphere, including their annnual and interannual variations and long-term trends. Various archived dynamics have been used by modellers to drive CTMs, including 3-D transport fields from general circulation models (GCMs) and data assimilation systems (DASs). We briefly review our zonal mean diagnostics package for evaluation of the transport properties of GCMs and DASs, highlighting some results that can be seen from the annual evolution of the monthly mean transport parameters. The package includes the trajectory code for particles dispersion and estimation of the zonal mean transport circulation and large-scale eddy mixing using the Eulerian tracer model.Comparative examples will be presented for the 2000 NCEP and ECMWF DASs, and MACCM2-95 GCM. The tracer model itself can be used to diagnose some subgrid vertical transport parameters from the global meteorological fields (e.g., convection and diffusion of tropospheric pollutants). We compare the first tropospheric CO retrievals from the MOPITT instrument on the Terra satellite with the CO-tracer simulations driven by the NCEP large-scale dynamics and convective transports that are estimated by different convective schemes from the NCEP archived history tapes.