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Laboratory for Atmospheric and Space Physics


Below are atmospheric and radiative transfer models utilized or maintained by the Toon Group. The group maintains an extensive wiki page with details on how to run many of these models.

Model: Community Aerosol Model (CAM3)

Source: NCAR/CGD

The latest version of NCAR’s CCM launched in May 2002 is part of a series of global atmosphere models developed for climate research communities. CAM also serves as the atmospheric component of the Community Climate System Model (CCSM).

Model: Community Aerosol and Radiation Model for Atmospheres (CARMA)

Source: University of Colorado, NASA Ames Research Center

CARMA is a general-purpose sectional microphysics code that has been used to study a wide variety of aerosols in planetary atmospheres. It originated from a one-dimensional stratospheric aerosol code developed by Turco et al. (1979) and Toon et al. (1979) that included both gas phase sulfur chemistry and aerosol microphysics. The model was improved and extended to three dimensions as described by Toon et al. (1988). Extensive updates of the numerics continue to be made. Standard versions of the model aimed at cirrus and stratus cloud physics are maintained at NASA Ames Research Center and distributed to the community. A wide community of users outside of NASA, including our group at the University of Colorado, works with this code and continues to improve it. The model has also been converted into an operational model for dust storm prediction by the U. S. Air Force.

CARMA applications
One-dimensional studies:
Chemistry in the marine troposphere (Toon et al., 1987); the Pinatubo volcanic cloud (Zhao, Turco and Toon, 1995); polar stratospheric clouds (Toon et al., 1989; Toon et al., 1990a); cirrus clouds (Jensen et al., 1994a,b); marine stratus clouds (Ackerman, Toon and Hobbs, 1993, 1994, 1995a,b); organic aerosols on Titan (Toon et al 1992); sulfuric acid clouds on Venus (James et al, 1997); ice clouds on Mars (Michelangeli et al., 1993, Colaprete et al., 1999)

Three-dimensional studies:
Wind-blown Saharan dust (Westphal et al., 1987, 1988; Colarco et al., 2002, 2003a, 2003b); biomass combustion smoke (Westphal and Toon, 1991a, 1991b); the Pinatubo eruption cloud (Young, Houben and Toon, 1994); and Martian dust storms (Murphy et al., 1991, 1995); meteoritic dust in the mesosphere (Bardeen et al., 2008); regional nuclear war and stratospheric ozone (Mills et al., 2008).

Model: Distributed Hydrodynamic Aerosol and Radiative Modeling Application (DHARMA)

Source: NASA Ames Research Center

The dynamics framework of DHARMA is a large-eddy simulation code originally called HUSCI and developed by David Stevens (now at LLNL) (Stevens and Bretherton, JCP, 1996). As a postdoc at LLBL, Dr. Stevens extensively rewrote the model to be massively parallel (with 2D decomposition) using MPI (Stevens et al., JAS, 2002). DHARMA also includes aerosol and cloud microphysics and radiative transfer components that are based on CARMA, which required making the microphysics model suitable for use in a 3D framework. To do so, during the 1990s at NASA Ames Research Center Eric Jensen and Andy Ackerman rewrote the aerosol and cloud microphysics model originally developed by Brian Toon and Rich Turco in the 1970-80s (Toon et al., 1988). This rewrite largely consisted of generalizing the particle bin structure, decoupling the time stepping of coagulation and condensation (making the latter time-stepping independent within each grid cell), and replacing the advection algorithms used for condensation and sedimentation. Then Dr. Ackerman merged CARMA (including it’s two-stream radiative transfer model, Toon et al. 1989) into the large-eddy simulation codes (first the serial version and later the parallel version). The name DHARMA was coined to described the massively parallel version of the merged model (the CARMA microphysics and radiative transfer components are optional components of DHARMA).

Model: Model for Atmospheric Transport and Chemistry (MATCh)

Source: NCAR/GCD, MIT/UCSB, Max Planck Institute for Chemistry

MATCH is an offline transport model developed primarily by Philip Rasch (NCAR), Brian Eaton (NCAR), Natalie Mahowald (MIT/UCSB), and Mark Lawrence (MPI-Mainz), with smaller contributions by many others. The base model has been developed at NCAR and the Center for Clouds, Chemistry and Climate (C4) at the Scripps Institution of Oceanography, a Science and Technology Center. Both NCAR and C4 are funded by the National Science Foundation.

Model: Model for Ozone And Related chemical Tracers (MOzART3)

Source: NCAR/ACD

The Model for OZone And Related chemical Tracers (MOZART) version 3 is an extension of the MOZART2 version discussed in: Brasseur et al., 1998; Hauglustaine et al., 1998; Horowitz et al., 2003. The numerical solution approach solves a system of time-dependent ordinary differential equations, primarily by two methods: explicit Euler and implicit backward Euler. Species with long lifetimes and weak forcing terms are solved with the explicit method (e.g., N2O), while species that comprise a “stiff system” with short lifetimes and strong forcings are solved via the more robust implicit method (e.g., OH).

Model: Whole-Atmospheric Community Climate Model (WACCM3)


The Whole-Atmosphere Community Climate Model (WACCM) is a comprehensive numerical model, spanning the range of altitude from the Earth’s surface to the thermosphere. The development of WACCM is an inter-divisional collaboration that unifies certain aspects from the High Altitude Observatory’s (HAO) modeling of the upper atmosphere, the Atmospheric Chemistry Division’s (ACD) modeling of the middle atmosphere, and the Climate and Global Dynamics Division’s (CGD), modeling of the troposphere, all of whom use the NCAR Community Climate System Model (CCSM) as a common numerical framework.