Chemical transport model

A chemical transport model (CTM) is a type of computer numerical model which typically simulates atmospheric chemistry and may give air pollution forecasting.

Chemical transport models and general circulation models

While related

; this allows feedbacks from the CTM to the GCM's radiation calculations, and also allows the meteorological fields forcing the CTM to be updated at higher time resolution than may be practical in studies with offline CTMs.

Types of chemical transport models

CTMs may be classified according to their methodology and their species of interest, as well as more generic characteristics (e.g. dimensionality, degree of resolution).

Methodologies

Jacob (1999)^[1] classifies CTMs as Eulerian/"box" or Lagrangian/"puff" models, depending on whether the CTM in question focuses on ^[1]

• (Eulerian) "boxes" through which fluxes, and in which chemical production/loss and deposition occur over time
• (Lagrangian) the production and motion of parcels of air ("puffs") over time

An Eulerian CTM solves its continuity equations using a global/fixed frame of reference, while a Lagrangian CTM uses a local/moving frame of reference.

See also

• discussion of gridding in CLaMS
• Lagrangian and Eulerian coordinates
• discussion of the continuity equation in Jacob's Introduction to Atmospheric Chemistry online

Examples of Eulerian CTMs

• CCATT-BRAMS
• WRF-Chem
• CMAQ, CMAQ Website
• CAMx
• GEOS-Chem
• LOTOS-EUROS
• MATCH
• MOZART: (Model for OZone And Related chemical Tracers) is developed jointly by the (
  aerosols
  .
• TOMCAT/SLIMCAT
• CHIMERE
• POLYPHEMUS
• TCAM (Transport Chemical Aerosol Model; TCAM): a mathematical modelling method (computer simulation) designed to model certain aspects of the Earth's atmosphere. TCAM is one of several chemical transport models, all of which are concerned with the movement of chemicals in the atmosphere, and are thus used in the study of air pollution.

TCAM is a

photochemical and aerosol) at mesoscales (medium scale, generally concerned with systems a few hundred kilometers in size).^[3]

TCAM was developed at the University of Brescia in Italy.^[4]

Examples of Lagrangian CTMs

• CLaMS
• FLEXPART

Examples of Semi-Lagrangian CTMs

• MOCAGE
• GEM-MACH

Examples of ozone CTMs

• CLaMS
• MOZART

Notes

External links

• Air Dispersion Modeling at
  Curlie
• MOZART:
  • UCAR's MOZART page
  • MPI-Met's MOZART page
  • Larry Horowitz's MOZART page

See also

• Atmospheric dispersion modeling
• List of atmospheric dispersion models
• University Corporation for Atmospheric Research
• National Center for Atmospheric Research
• Ozone depletion
• Meteorology