Welcome to the SCCM Home Page 

The NCAR Single-column Community Climate Model

What is SCCM?

The SCCM is a one-dimensional time-dependent version of the NCAR Community Climate Model, often referred to as a Single Column Model (SCM). The local time-rate-of-change of the large-scale state variables (e.g., temperature, moisture, momentum, cloud water, etc.) depend on specified horizontal flux divergences, a specified vertical motion field (from which the large-scale vertical advection terms are evaluated), and subgrid-scale sources, sinks and eddy transports. The subgrid-scale contributions are determined by an arbitrary collection of user-selected subgrid-scale physics parameterizations. At present, the software distribution will build either a CCM2 SCM, or a CCM3 SCM along with its more sophisticated land surface model. All physics parameterization modules are identical in coding structure to their respective counterparts in the more complete CCM2 and CCM3 distributions, so that components can be trivially migrated between the two modeling frameworks.

The overall design includes the provision of a graphical user interface (GUI) to the model. This approach has required an integration of the FORTRAN-based CCM physics with the C++-based GUI which presently restricts the modeling framework to more mature computational environments (such as scientific workstation environments - note however the recent port to the Intel x86/Linux platform). The point-and-click graphical interface streamlines the control of code flow including: dataset selection; column location (latitude/longitude) selection; modification of control variables (such as termination conditions, update frequencies, specification of history data, etc.); modification of initial data and the associated large-scale forcing (e.g., modification of vertical structures, amplitudes, etc.); and the visualization of output data (vertical profiles, time series, etc.). In particular, we have emphasized a tight coupling of interactive graphical analysis capabilities with the integration component of the model. Both semi-Lagrangian and Eulerian vertical advection capabilities have been incorporated into the modeling framework, allowing flexible solution of vertical advection terms for an arbitrary number of model variables (including the standard state variables).

A generalized netCDF data format has been adopted for describing input and output datasets for this modeling environment, where filters have been created for transparently converting between netCDF and CCM history tape formats. In addition to CCM-generated initial and boundary condition datasets the modeling framework has been constructed to incorporate data (e.g., initial conditions and forcing terms) as diagnosed from various field experiments. The current standard "library" of field program forcing/budget data includes GATE, TOGA COARE, and ARM IOP datasets. These initial condition and forcing data are dynamically specifiable from the GUI, as are global initial conditions and steady-state vertical motion forcing data from ECMWF analyses and CCM climate integrations. The IOP data serves a dual role by providing the necessary boundary forcing for the one-dimensional model, and providing validation data for the time-dependent solutions generated by the collection of physical parameterizations which are being evaluated.

This modeling framework has been under development for several years, with support from the Computer Hardware Advanced Mathematics Model Physics (CHAMMP) Program, currently known as the Climate Change Prediction Program (CCPP), which is administered by the Office of Energy Research under the Office of Health and Environmental Research in the Department of Energy Environmental Sciences Division. During this development period we have been systematically evaluating the strengths and weaknesses of an SCM approach (a manuscript is in preparation). Despite certain limitations, it has proven to be an economical numerical experimentation environment for facilitating the investigation and improvement of parameterizations of radiative and moist processes in atmospheric general circulation models. We believe that the current code distribution is sufficiently stable so that the community will be able to build and execute the code in any of the common UNIX environments to which is has been ported:  currently supported systems are Sun/Solaris, IBM RS6000/AIX, SGI/IRIX64, HP/HP-UX and Intel PC/Linux. DEC/OSF1  will be supported in the near future.

The code is an UNSUPPORTED contribution to the university modeling community, although we do wish to receive feedback on any problems users may encounter (sccm@cgd.ucar.edu). Users are strongly encouraged to register their use of SCCM so that they may automatically receive notification of program updates, new dataset availability, etc.  Users may register by sending email to sccm@cgd.ucar.edu with the subject "registration."

!!! Bulletins !!!

Known Problems and Bugs

Release History

SCCM Source Code, GUI, and Dataset Distribution

The graphical user interface (GUI) is only available as a precompiled binary so you must download the correct version for your system and compiler.

Global Initial Conditions and Boundary Datasets

IOP Datasets




There are none at this time.

Related Sites

NCAR Community Climate Models


NCAR Home Page

NCAR/CMS Home Page



ARM SCM Intercomparison Home Page

Single Column Modeling Home Page

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Page last modified February 10, 1999