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User's Guide to NCAR CAM2.0

Appendix A: Glossary

branch run A type of continuation run of the CAM. A branch run starts a new case using the restart files from a previous model run. This is used primarily when you wish to exactly reproduce a control simulation, but change the output fields.
CAM Community Atmosphere Model; the latest atmosphere model code which can be run as part of the CCSM or as a stand-alone atmosphere model for climate prediction.
case A term used to denote a model experiment, including one initial run and as many continuation runs as required to conclude the experiment. A model case is cataloged using the CASEID namelist variable. By default the caseid is included in the output filenames and mass store archive path.
cc "C" language compiler.
CCM Community Climate Model; the predecessor model code of CAM used in making climate predictions.
CCSM Community Climate System Model. The set of geophysical models for atmosphere, land, ocean, and sea-ice to model the climate system. CAM is the atmosphere model component for the CCSM.
CPP C preprocessor.
continuation run A type of run that uses a restart file from a previous run to initialize the data fields (no initial dataset is read). Restart and branch runs are each possible types of a continuation run.
CSEG CCSM Software Engineering Group. The group of software developers at NCAR responsible for maintaining and developing the CCSM codes.
CLM The Community Land Model a land surface model.
CPU Central Processing Unit.
CSIM Community Sea-Ice Model.
distributed memory Multi-processing on multiple CPU's using the SPMD programming model.
DOM Data Ocean Model. Ocean component of stand-alone CAM that reads in SST information from an input dataset.
ECMWF European Center for Medium Range Weather Forecasting
ESMF Earth System Modeling Framework
FV The Finite-Volume (also referred to as Lin-Rood) dynamical core.
flux-coupled A simulation with the atmosphere model where the model is linked to a system of geo-physical models (land, ocean, and sea-ice). When run in this manner each seperate component is built as a seperate executable, and each component communicates with each other in Multiple Program - Multiple Data (MPMD) mode. See also CCSM.
GNU GNU's not UNIX. A set of Open-Source freely provided utilities for UNIX.
gzip GNU decompression utility similar to UNIX uncompress. Takes a file and inflates it to it's full size so that it can be used. Files are compressed to save disk space and save on network file transfer times.
header file A file containing CPP tokens to set the particular model resolution and configuration named with a ".h" suffix (e.g. misc.h).
heap Memory that is dynamically allocated by the system. Unlike stack memory, heap memory can be allocated or de-allocated at any point during program execution.
history file The output NetCDF dataset that the model produces to record the model simulation field values with time.
initial run A startup simulation using a initial-condition dataset.
LSM The NCAR Land Surface Model. This model was used with the CCM the predecessor to CAM.
module A FORTRAN-90 construct containing data and subroutines and functions that operate on that data. This is a somewhat object-oriented approach to datastructures. The data can be specified as private to the module or public for access by other subroutines. Outside subroutines can specify the limited set of variables they wish to capture. This ability provides a better approach to handling data and is the preferred method for dealing with data over COMMON blocks.
MPI Message Passing Interface. A standardized library for distributed memory parallel processing.
MPMD Multiple Program Multiple Data. Parallel programming model with several distinct executable programs operating on different sets of data.
mpxlf90 FORTRAN-90 compiler for IBM AIX with message passing (MPI) libraries included.
mpxlf90_r Thread-safe FORTRAN-90 compiler for IBM AIX with message passing (MPI) libraries included, and allowing for Open-MP threading.
MSS The NCAR Mass Store System.
multi-tasked A program configured to execute on several distributed processors simultaneously. See distributed memory.
NCAR National Center for Atmospheric Research
NetCDF Network Common Data Format. Self describing, platform independent binary data format (created by UNIDATA).
OpenMP Open specification for Multi-Processing. Set of compiler directives for shared-memory parallel processing, that is supported by most compiler venders.
PBL Planetary Boundary Layer.
pcnst Number of advected constituents carried in the model.
pgf90 Portland Group's FORTRAN-90 compiler,
plat Number of Gaussian latitudes on the transform grid.
plev Number of vertical model levels.
plon Number of longitudes on the transform grid
restart run A type of continuation run of the CAM. A restart run continues a previous run from its point of termination, by reading most recent restart
single-threaded Parallel-processing term. Refers to the parts of shared memory processed code that executes on only one processor. 
shared-memory Parallel-processing term. Refers to using a machine where multiple CPU's share the same memory.
SLT Semi-Lagrangian Transport.
SPMD Single Program Multiple Data.
stack Memory local to a subroutine or function.
stand-alone Running the model not in flux-coupled mode as described above, but as a single-executable with land, thermodynamic sea-ice, and data ocean models as subroutines of the main executable.
STDERR Standard error. Output stream that error messages are sent to. Usually, this is the users terminal.
STDOUT Standard output. Default output stream that messages are sent to. Usually, this is the users terminal.
transform grid A grid used to evaluate all nonlinear and diabatic forcing terms in physical space.
UNIDATA University Atmospheric Data access project funded by the National Science Foundation (NSF).
UNIX A modern operating system shared and supported by most supercomputers.

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$Name: $ $Revision: 1.1 $ $Date: 2004/06/08 02:57:20 $ $Author: jmccaa $