TOMCAT/SLIMCAT

TOMCAT/SLIMCAT is an off-line chemical transport model (CTM), which models the time-dependent distribution of chemical species in the troposphere and stratosphere. It can be used to study topics such as ozone depletion and tropospheric pollution, and was one of the models used the IPCC report on Aviation and the Global Atmosphere . It incorporates a choice of detailed chemistry schemes for the troposphere or stratosphere, and an optional chemical data assimilation scheme.

The original model code, called the Toulouse Off-line Model of Chemistry And Transport (TOMCAT), was written by Martyn Chipperfield at Météo France. "Off-line" in this sense describes the fact that although the meteorological data (wind components and other fields) which are used as input to the CTM typically derive from a general circulation model (GCM), the CTM is run as a separate program outside of a GCM; this is as distinct from a chemistry simulation scheme which runs within a GCM, in which the simulated chemical distributions, e.g. of ozone, can provide feedback on the meteorology via the GCM's radiation scheme.

A version called the Single Layer Isentropic Model of Chemistry And Transport (SLIMCAT) was developed in 1995. This used a level of constant potential temperature (or equivalently, of constant specific entropy, hence isentropic), exploiting the fact that due to approximate conservation of energy, atmospheric motions are approximately adiabatic and hence air parcels remain on isentropic levels on short timescales. A diabatic heating scheme was later added, to allow for multiple isentropic levels with transport between them on longer timescales, although the name "SLIMCAT" has remained despite the multiple levels.

The two programs are now maintained as a single code base, which runs in Fortran, and has been parallelised.

TOMCAT has been further extended to include a detailed treatment of aerosol. GLOMAP (Global Model of Aerosol Processes) simulates a wide range of aerosol species including black carbon, sulfate, sea spray, soil dust, and secondary organic aerosol. The primary purpose of TOMCAT/GLOMAP is to simulate aerosol radiative forcing and the impact of aerosol on climate.

References

Chipperfield, M.P., New Version of the TOMCAT/SLIMCAT Off-Line Chemical Transport Model: Intercomparison of Stratospheric Tracer Experiments, Q. J. R. Meteorol. Soc., 132, 1179–1203, 2006.
Spracklen, D.V., Pringle, K.J., Carslaw, K.S., Chipperfield, M.P. and Mann, G.W., A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties, Atmospheric Chemistry and Physics, Vol. 5, 2227-2252, 2005.

External links

TOMCAT/SLIMCAT Project homepage at University of Leeds, UK (with further published references)
GLOMAP Project page

Atmospheric, oceanographic and climate models

Model types

Atmospheric model Climate model Numerical weather prediction Tropical cyclone forecast model Atmospheric dispersion modeling Chemical transport model Upper-atmospheric models Ensemble forecasting Model output statistics Meteorological reanalysis Parametrization

Specific models

Climate	IGCM HadCM3 HadGEM1 GFDL CM2.X CGCM CCSM CFSv2 ECHAM MPAS

Global weather	IFS (ECMWF) FIM GEM GFS NAVGEM UM JMA GME ARPEGE

Regional and mesoscale atmospheric	NAM RR / RAP RAMS WRF RAQMS HIRLAM LAPS RPM

Regional and mesoscale oceanographic	HyCOM ROMS POM MOM FVCOM MITgcm

Atmospheric dispersion	ADMS AERMOD ATSTEP AUSTAL2000 CALPUFF DISPERSION21 ISC3 MEMO MERCURE NAME OSPM PUFF-PLUME RIMPUFF SAFE AIR

Chemical transport	CLaMS MOZART GEOS-Chem

Land surface parametrization	JULES CLASS ISBA

Discontinued	AVN / MRF / GSM Eta LFM MM5 NGM NOGAPS RUC

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