Modeling
Chemical, physical, and biological processes within the atmosphere are both
complex and non-linear. Numerical models can assist in
the understanding of atmospheric chemistry through their ability to represent all of
these processes, or exclude them individually. The advent of today's supercomputing
technology has allowed for atmospheric models on spatial and temporal scales only
dreamed of ten years ago.
ACD is actively involved in numerous modeling efforts from depletion of the ozone to
pollution tracking on both regional and global scales.
ACD modeling supports the major ACD research themes of regional and global air quality and chemistry and climate change. Detailed process models explore extensive sets of reactions and their sensitivities to reaction rates, background composition, and other variables. Global and regional models can be run for specific periods to compare with field observations and to test and improve our understanding of the interactive dynamical-chemical system. Such model runs in advance of measurement campaigns are also useful for planning. ACD is leading the development and analysis of the chemical component of NCAR global community models (CCSM, WACCM). These models are advanced tools for diagnosing and predicting climate change and the interactions between atmospheric composition, climate, land surface and biosphere.
Models
| Model | Download | Technical Support | Information |
|---|---|---|---|
| MEGAN | Download | Alex Guenther: guenther@ucar.edu | MEGAN is a modeling system for estimating emission and uptake (exchange) of gases between the atmosphere and terrestrial vegetation and soils (Nature). MEGAN uses an approach similar to previous models (e.g., BEIS, BEIS2 and GLOBEIS) but is intended to be easier to use and update and to incorporate into regional and global chemistry and transport models. |
| MOZART | Download | Louisa Emmons: emmons@ucar.edu | MOZART is a comprehensive global chemical transport model of atmospheric composition designed to simulate tropospheric chemical and transport processes. It is driven by standard meteorogical fields output from any number of meteorological centers (e.g. the National Centers for Environmental Prediction (NCEP), European Centre for Medium Range Weather Forecasts (ECMWF), or Global Modeling and Assimilation Office (DMAO)) or by fields generated from general circulation models. |
| SOCRATES | Download | Anne Smith: aksmith@ucar.edu | SOCRATES is an interactive chemical dynamical radiative two-dimensional (2-D) model. |
| TUV | Download | Sasha Madronich: sasha@ucar.edu | TUV is an interactive model (written in F77) for calculating solar visible and ultraviolet radiation in the Earth's atmosphere, with emphasis on the troposphere (lower atmosphere and surface). The model produces spectral irradiances and actinic fluxes, biologically weighted radiation, and photodissociation rate coefficients, for user-specified location, date, time, surface reflectivity and elevation, ozone column, cloud thickness, and aerosols. Extensive in-line documentation facilitates customization of the code for many different applications. The user must have F77 on their system in order to compile and run TUV, or download the pre-compiled Windows (98, XP) version. |
| NCAR Master Mechanism | Download | Julia Lee-Taylor: julial@ucar.edu | The NCAR Master Mechanism is an explicit and detailed gas phase chemical mechanism combined with a box model solver. User inputs include species of interest, emissions, temperature, dilution, and boundary layer height. Any input parameter may be constrained with respect to time. Photolysis rates are calculated using the TUV model, included in the code package. The model is written in a mixture of F77 and Fortran90, and is managed using C-shell scripts. |
| WACCM | Download | Rolando Garcia: rgarcia@ucar.edu | 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 of the upper atmospheric modeling of HAO, the middle atmosphere modeling of ACD, and the tropospheric modeling of CGD, using the NCAR Community Climate System Model (CCSM) as a common numerical framework. |