The EDSS/Models-3 I/O API


NOTES:
The Models-3 I/O API is not a data format !!

I/O API files are not synonymous with netCDF files !!
Instead, netCDF is one of four distinct lower layers on which the data and metadata structures for I/O API files are currently available; additional lower layers may very well be incorporated at various times in the future (Does anyone want to fund development of an MPI 2 lower layer? -- Contact the author!)


The Models-3/EDSS Input/Output Applications Programming Interface (I/O API) provides the environmental model developer with an easy-to-learn, easy-to-use programming library for data storage and access, available from both Fortran and C. The same routines can be used for both file storage (using netCDF files) and model coupling (using PVM mailboxes). It is the standard data access library for both the NCSC/CMAS's EDSS project and EPA's Models-3. There is a external-package wrapper for the I/O API in the Weather Research and Forecasting Model [WRF], which optionally uses I/O API coupling mode to couple WRF-Chem with SMOKE.

The I/O API provides a variety of data structure types for organizing the data, and a set of access routines which offer selective direct access to the data in terms meaningful to the modeler. For example,

Read layer 1 of variable 'OZONE' from 'CONCFILE' for 5:00 PM GMT on July 19, 1988 and put the result into array A.
is a direct English translation of a typical I/O API READ3() call. "Selective direct access" means that this READ3 call retrieves exactly this ozone data immediately. It does not have to read through previous hours of data, nor whatever other variables (such as NOX or PAN) are in the file. Data can be read or written in any order (or not at all). This characteristic provides the following advantages: I/O API files also have the following characteristics

The I/O API also contains an extensive set of utility routines for manipulating dates and times, performing coordinate conversions, storing and recalling grid definitions, sparse matrix arithmetic, etc., as well as a set of data-manipulation and statistical analysis programs. It has an extensive documentation set, including

Various extensions and research efforts to the I/O API have been developed or are under development. Developments include the use of the I/O API interacting with PVM for model coupling, and adding operations to read or write entire time series (with multiple time steps) as single operations, and research projects include data-parallel I/O and a very powerful "geospatial cell complex" data type with polygonal-cell decompositions that may be both time independent (as for finite elememt modeling) and time dependent (as for moving-mesh plume-in-grid modeling).

are copyright © 1992-2002 MCNC and Carlie J. Coats, Jr., 2003-2005 by Baron Advanced Meteorological Systems (hereinafter, BAMS), and © 2005-2013 Carlie J. Coats, Jr.. The I/O API source code and documentation are copyright 1992-2002 MCNC and Carlie J. Coats, Jr., 2003-2013 by Baron Advanced Meteorological Systems (hereinafter, BAMS), and © 2005-2013 Carlie J. Coats, Jr. and distributed under the GNU Lesser (library) Public License (LGPL) Version 2.1, subject to copyright-statement retention constraints. See the Notices: Copyright, and Acknowledgements page.

    $Id: index.html 1925 2014-02-01 14:39:17Z coats@borel $