Marina Tsidulko

Linking the Eta Model with the Community Multiscale Air Quality (CMAQ) Modeling System to Build a National Air Quality Forecasting System

Abstract NOAA and the U.S. Environmental Protection Agency (EPA) have developed a national air quality forecasting (AQF) system that is based on numerical models for meteorology, emissions, and chemistry. The AQF system generates gridded model forecasts of ground-level ozone (O3) that can help air quality forecasters to predict and alert the public of the onset, severity, and duration of poor air quality conditions. Although AQF efforts have existed in metropolitan centers for many years, this AQF system provides a national numerical guidance product and the first-ever air quality forecasts for many (predominantly rural) areas of the United States. The AQF system is currently based on NCEP’s Eta Model and the EPA’s Community Multiscale Air Quality (CMAQ) modeling system. The AQF system, which was implemented into operations at the National Weather Service in September of 2004, currently generates twice-daily forecasts of O3 for the northeastern United States at 12-km horizontal grid spacing. Preoperationa...

Impact of Domain Size on Modeled Ozone Forecast for the Northeastern United States

Abstract This study investigates the impact of model domain extent and the specification of lateral boundary conditions on the forecast quality of air pollution constituents in a specific region of interest. A developmental version of the national Air Quality Forecast System (AQFS) has been used in this study. The AQFS is based on the NWS/NCEP Eta Model (recently renamed the North American Mesoscale Model) coupled with the U.S. Environmental Protection Agency Community Multiscale Air Quality (CMAQ) model. This coupled Eta–CMAQ modeling system provided experimental air quality forecasts for the northeastern region of the United States during the summers of 2003 and 2004. The initial forecast over the northeastern United States was approved for operational deployment in September 2004. The AQFS will provide forecast coverage for the entire United States in the near future. In a continuing program of phased development to extend the geographical coverage of the forecast, the developmental version of AQFS has...

Incremental Development of Air Quality Forecasting System with Off-Line/On-Line Capability: Coupling CMAQ to NCEP National Mesoscale Model

The National Air Quality Forecast Capability (NAQFC) is based on the EPA Community Multiscale Air Quality (CMAQ) model driven by meteorological data from the NOAA North American Mesoscale (NAM) Non-hydrostatic Meso-scale Model (NMM). Currently, NMM meteorological data on Arakawa E-grid are interpolated on a CMAQ’s Arakawa C-grid using the processors PRODGEN and PREMAQ to handle map-projection transform, vertical layer collapsing, and other emission and meteorological data feed issues. The FY11 pre-implementation version of NAM has undergone significant changes in the vertical layering, horizontal grid projection and improved science components for its FY11 upcoming major upgrade release. This provides an opportunity to improve the coupling methodology between NMM and CMAQ that reduces uncertainties both in the meteorological and emission inputs for the off-line air quality modeling and helps development of on-line NMM-CMAQ version. Three major tasks are needed to achieve a tighter coupling between them: (1) Adapt to NAM’s vertical hybrid pressure and grid structure; (2) Change CMAQ to use the same rotated latitude longitude B staggered horizontal grid structure as NAM, (3) Modify emission model to provide generic inputs for the B staggered grid and hybrid vertical structure of NAM. The first task achieves consistent matching of dynamics between the two systems, despite the possible necessity of layer-collapsing to fit within operational time-lines. The second task removes unnecessary interpolation of meteorology data for air quality simulations. The third task involves modification of the U.S. EPA Sparse Matrix Object Kernel Emission (SMOKE) model to handle the staggered B grid. At this time only the first of these three steps has been accomplished, and the test result from this test focusing on the selected test period has been compared to that produced by the operational NAQFC. Further work with all these three modifications concurrently in place is underway.

Linking the ETA Model with the Community Multiscale Air Quality (CMAQ) Modeling System: Ozone Boundary Conditions

Until the recent decade, air quality forecasts have been largely based on statistical modeling techniques. There have been significant improvements and innovations made to these statistically based air quality forecast models during past years (Ryan et al., 2000). Forecast fidelity has improved considerably using these methods. Nonetheless, being non-physically-based models, the performance of these models can vary dramatically, both spatially and temporally. Recent strides in computational technology and the increasing speed of supercomputers, combined with scientific improvements in meteorological and air quality models has spurred the development of operational numerical air quality prediction models (e.g., Vaughn et al., 2004, McHenry et al., 2004). In 2003, NOAA and the U.S. Environmental Protection Agency (EPA) signed a memorandum of agreement to work collaboratively on the development of a national air quality forecast capability. Shortly afterwards, a joint team of scientists from the two agencies developed and evaluated a prototype surface ozone concentration forecast capability for the Eastern U.S. (Davidson et al., 2004). The National Weather Service (NWS) / National Centers for Environmental Prediction (NCEP) ETA model (Black, 1994, Rogers et al., 1996, and Ferrier et al., 2003) with 12-km

Chapter 5.2 Aerosol forecast over the Great Lakes for a February 2005 episode

Abstract Many air pollution agencies in the Upper Midwest and the Great Lakes regions in the U.S. had issued air advisories between January 31 and February 4, 2005. Air Quality Index (AQI) issued on the EPA web site for Minnesota peaked at 155 on January 31. In the Chicago area, AQI measured between 110 and 140 for most of this first week of February. The deterioration of the air quality over these regions for a rather prolonged duration had been attributed to the slow passing of broad high pressure systems centered over the Great Lakes during the period. The pressure systems were accompanied by extensive cloudiness and snow coverage over the same regions. This combination of meteorological conditions resulted in reduced atmospheric mixing; and high rates of atmospheric particle formation and growth due to high RH in the lower levels. In this study, the National Weather Services (NWS) Eta-CMAQ Air Quality Forecast System (AQFS) has been used in a research mode to predict the aerosol concentration and speciation of this poor air episode. The model result has been verified in a crude manner by comparing its Aerosol Optical Depth (AOD) prediction with that observed by the Geostationary Operational Environmental Satellites (GOES), and surface level aerosol concentration prediction with that compiled by the Aerometric Information Retrieval Now (AIRNOW) observation network. Qualitatively speaking, the predicted results are comparable to these aforementioned observed fields. Further analysis of the model results suggested a largely anthropogenic nature of the particulate matter in the lower atmosphere over the regions of high AQI in the period.