You are here:
COMPUTATIONAL ASPECTS OF THE AIR QUALITY FORECASTING VERSION OF CMAQ (CMAQ-F)
Citation:
Wong, D. C. AND J O. Young. COMPUTATIONAL ASPECTS OF THE AIR QUALITY FORECASTING VERSION OF CMAQ (CMAQ-F). Presented at 2004 Models-3 Conference, Chapel Hill, NC, October 18 - 20, 2004.
Impact/Purpose:
The objectives of this task include: (1) to continuously evaluate and analyze the forecast results to provide diagnostic information on model performance and inadequacies to guide further evolution and refinements to the CMAQ model, and (2) extending the utility of the daily air quality forecast model data being produced by NOAA's National Weather Service (NWS) as part of a NOAA/EPA collaboration in air quality forecasting, to EPA mission-oriented activities. These objectives include developing and maintaining a long-term database of air quality modeling results (ozone and PM2.5), performing periodic analysis and assessments using the data, and making the air quality database available and accessible to States, Regions, RPO's and others to use as input data for regional/local scale air quality modeling for policy/regulatory purposes.
Description:
The air quality forecast version of the Community Modeling Air Quality (CMAQ) model (CMAQ-F) was developed from the public release version of CMAQ (available from http://www.cmascenter.org), and is running operationally at the National Weather Service's National Centers for Environmental Prediction (NCEP). Most of the modifications to CMAQ focus on tailoring the model's performance to the operational hardware and the parallel computing environment at NCEP and effectively managing the parallel input and output (I/O) processes to achieve scalability. This has been accomplished by asynchronously overlapping computation with I/O writing to disk (WTD) by a dedicated processor.
In this paper, we describe two different ways of placing the WTD processor. Benchmark results with regards to the WTD processor placement and an extension to more than one WTD processor are presented. In addition, a benchmark comparison between the I/O implementation in the CMAQ-F and the community version of CMAQ is provided.
The research presented here was performed under the Memorandum of Understanding between the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) and under agreement number DW13921548. Although it has been reviewed by EPA and NOAA and approved for publication, it does not necessarily reflect their policies or views.