Science Inventory

METEOROLOGICAL AND TRANSPORT MODELING

Impact/Purpose:

This task objective is the development and improvement of state-of-the-science meteorology models and contributing process parameterizations for use in advanced air quality simulation model systems such as the Community Multi-scale Air Quality (CMAQ) modeling system and for other modeling studies and situations involving transport and dispersion of pollutants. Components of this work include: (a) improved meteorological and transport modeling, (b) improved meteorological modeling physics, (c) physical modeling of flows- building wakes, complex terrain, urban canyons, (d) modeling of transport and dispersion of specialized situations and (e) develop AERMOD (AMS/EPA Regulatory MODel).

Description:

Advanced air quality simulation models, such as CMAQ, as well as other transport and dispersion models, require accurate and detailed meteorology fields. These meteorology fields include primary 3-dimensional dynamical and thermodynamical variables (e.g., winds, temperature, moisture, cloud and rain water, and pressure), as well as an extensive set of 2-dimensional fields (e.g., surface turbulent fluxes, land-use parameters, radiation fields, and planetary boundary layer (PBL) depth). By design, even the most sophisticated mesoscale meteorology models (e.g., MM5) cannot fully account for sub-grid scale processes. Thus, model forecasts tend to decrease in skill through the simulation period. Yet, to support air quality modeling, meteorological models are typically run retrospectively for a longer simulation than general forecasting applications, so it becomes particularly important to control the error through the duration of the run. It is also more difficult to effectively apply the model at finer spatial scales where local effects (e.g., small-scale terrain and land-use variations, coastal processes) become more important and where routine observations cannot adequately capture the meteorological characteristics in the region of interest. The failure of the meteorological model to capture local phenomena will adversely impact the predictions of air quality and dispersion models. As air quality modeling studies move to higher resolutions (e.g., 1-12 km), the work with the meteorology model will be focused on these resolutions and improving the simulation of local phenomena. Improvements to the meteorology models are proposed in three primary areas: model initialization, model physics, and data assimilation. Improvements to dispersion models for local scale situations are also undertaken. Evaluation of new techniques in the meteorological model and their subsequent impact on the air quality model will be addressed in Task 3874.

This task utilizes high performance computing and scientific visualization resources provided by EPA's National Environmental Scientific Computing Center (NESC2).

Record Details:

Record Type: PROJECT
Start Date: 07/01/1998
Completion Date: 09/30/2002
Record ID: 15866

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL EXPOSURE RESEARCH LABORATORY

ATMOSPHERIC MODELING DIVISION

ATMOSPHERIC MODEL DEVELOPMENT BRANCH