Meteorological Conditions During an Ozone Episode in Dallas‐Fort Worth, Texas, and Impact of Their Modeling Uncertainties on Air Quality Prediction

Abstract

The Southern Great Plains experiences an unhealthy level of ozone (O3) at times. The formation mechanisms contributing to these O3 events are not always clear and in some cases are related to particular atmospheric circulation patterns. A severe O3 pollution event on 27 August 2011 in the Dallas‐Fort Worth (DFW) area is investigated with a combination of observations and simulations using the Weather Research and Forecasting model with Chemistry (WRF/Chem). During the O3 episode, a stationary front with a stagnant zone at the leading edge persisted to the west of DFW. At the time, Hurricane Irene was located in western Atlantic, displacing the Bermuda Subtropical High and affecting the circulations over the Southern Great Plains. The stagnant zone confined the pollutant plume originating from DFW, leading to accumulation of primary pollutants and prominent O3 formation. Emission sources from a few urban areas east of DFW as well as power plants near Mount Pleasant and Carthage also contributed to this DFW O3 pollution episode. This scenario is different from the typical summer days over the Southern Great Plains when southerly winds prevail along the west edge of the Bermuda High and the pollutant plumes from DFW are advected downstream, resulting in low O3. Ensemble WRF/Chem predictions driven by the operational Short‐Range Ensemble Forecast outputs are conducted to examine the impact of meteorological uncertainties (particularly transport uncertainties) on air quality forecasting. The ensemble mean gives a better prediction in terms of plume directions than individual members.

Dynamical Downscaling of CO2 in 2016 Over the Contiguous United States Using WRF‐VPRM, a Weather‐Biosphere‐Online‐Coupled Model

“…Strength and frequency of cold fronts associated with midlatitude baroclinic cyclones play important roles to modulating the abundance of trace gases over the United States (Hu, Xue, et al, 2019; Leibensperger et al, 2008). Cold fronts often push polluted continental air out over the Atlantic and replace it with cleaner air, thus improving air quality in the United States (Leibensperger et al, 2008).…”

What have we missed when studying the impact of aerosols on surface ozone via changing photolysis rates?

“…The model system used in this study, the WRF-Chem model, is a fully coupled "online" 3-D Eulerian meteorological and chemical transport model that has been globally applied in air quality research (Tie et al, 2013;Zhang et al, 2014;Gao et al, 2018b;Hu et al, 2019). The version of the WRF-Chem model we used in this study is 3.9.1.1, and detailed introductions of the meteorological parts and chemical parts can be found in Skamarock et al (2008) and Grell et al (2005), respectively.…”

Terrestrial CO2 Fluxes, Concentrations, Sources and Budget in Northeast China: Observational and Modeling Studies

“…The high-temporal-resolution EC measurements of CO 2 fluxes and concentrations over diverse biomes crossing wide latitudes have been widely applied to optimize model parameters and validate modeling results (Dayalu et al, 2018;Hilton et al, 2013;Jamroensan, 2013;Mahadevan et al, 2008;Yuan et al, 2014). In addition, column-averaged CO 2 concentrations (XCO 2 ) retrieved from satellites are effective to constrain CO 2 fluxes and can be used to evaluate simulation results on wide spatial scales, especially in the regions with limited in situ measurements (Basu et al, 2013;Crowell et al, 2019;Hu et al, 2019bHu et al, , 2020Rayner et al, 2014;Rayner & O'Brien, 2001). CO 2 flux distribution and variation are heavily influenced by meteorological conditions.…”

“…The subsequent study indicated that the WRF-VPRM was able to capture the atmospheric CO 2 temporal and spatial distributions and performed better than other global models in simulating diurnal variability of atmospheric CO 2 concentration field (Ahmadov et al, 2009). In the past decade, the application and evaluation of WRF-VPRM mainly focused on North America (Feng et al, 2016;Hu et al, 2019bHu et al, , 2020Park et al, 2018;Ye et al, 2017) and Europe (Pillai et al, 2011). The model performances remain unknown in Asia including China due to the lack of observations, as well as model uncertainties due to uncertainties of VPRM parameters in the region (Dayalu et al, 2018;Hilton et al, 2013;Liu et al, 2015;Zhang et al, 2017a).…”