Project Number: 22-008

Research

Title: Modeling analysis of TRACER-AQ and over-water Measurements to improve prediction of on-land and offshore ozone

Institution(s) Represented: University of Houston (PI: Yuxuan Wang, Co-PI: James Flynn), St. Edward's University (Co-PI: Paul Walter)

Lead PI: Yuxuan Wang

AQRP Project Manager: Elena McDonald-Buller

TCEQ Project Liaison: Barry Exum

Awarded Amount: $181,724.00

Abstract

The Tracking Aerosol Convection ExpeRiment-Air Quality (TRACER-AQ) study, including the Galveston Offshore Ozone Observations (GO3) field campaign, provided unprecedentedly rich observations of ozone air pollution covering both offshore and onshore locations that are needed to validate current air quality models. During the TRACER-AQ period (July - October 2021), there were six multi-day ozone episodes, resulting in over 20 days during which at least one land-based site or ship-based measurement with Maximum Daily 8-hour Average (MDA8) ozone concentrations exceeded the current National Ambient Air Quality Standard (NAAQS) of 70 ppbv. The project team's preliminary analysis of TRACER-AQ observations has revealed definitive gaps in the Weather Research and Forecasting (WRF) model and WRF-driven photochemical models in replicating the observations. This AQRP project will address these issues via continued efforts of model-observation comparisons and photochemical model intercomparisons using three models driven by the same high-resolution WRF meteorology and emissions (CAMx, WRF-GC, and WRF-Chem). The activities are designed to focus on the following primary science questions:

Which configurations and simulation settings of WRF most accurately replicate the extensive meteorological data collected as part of TRACER-AQ?
How well do coupled mesoscale meteorological and photochemical grid modeling of coastal/maritime boundary layers replicate observations?
How well do photochemical grid models predict over-water concentrations and formation rates of ozone?
What are the spatial distributions of ozone and ozone precursors during TRACER-AQ on days with on-land monitors recording exceedances of the NAAQS and how well does the photochemical model predict such distributions?
Which emission source categories affect ozone formation over Galveston Bay and the Gulf of Mexico?

The project specifically targets the AQRP Priority Research Area FY2022-2023: TRACER-AQ and over-water measurements. The project will lead to improvements in meteorological and photochemical models to better simulate on-land and offshore ozone in the Houston-Galveston-Brazoria (HGB). The model intercomparison will characterize the strengths and weaknesses of the regulatory model, CAMx, in the context of other air quality models. The modeling interpretation of TRACER-AQ observations will better understand offshore O3 formation and transport and their effects on high ozone episodes on land that directly relate to ozone exceedances.

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Research

Research

FY 2022 - 2023

Project Number: 22-008