Evolution of ozone, particulates, and aerosol direct radiative forcing in the vicinity of Houston using a fully coupled meteorology‐chemistry‐aerosol model

Abstract

[1] A new fully coupled meteorology-chemistry-aerosol model is used to simulate the urban-to regional-scale variations in trace gases, particulates, and aerosol direct radiative forcing in the vicinity of Houston over a 5 day summer period. Model performance is evaluated using a wide range of meteorological, chemistry, and particulate measurements obtained during the 2000 Texas Air Quality Study. The predicted trace gas and particulate distributions were qualitatively similar to the surface and aircraft measurements with considerable spatial variations resulting from urban, power plant, and industrial sources of primary pollutants. Sulfate, organic carbon, and other inorganics were the largest constituents of the predicted particulates. The predicted shortwave radiation was 30 to 40 W m À2 closer to the observations when the aerosol optical properties were incorporated into the shortwave radiation scheme; however, the predicted hourly aerosol radiative forcing was still underestimated by 10 to 50 W m À2 . The predicted aerosol radiative forcing was larger over Houston and the industrial ship channel than over the rural areas, consistent with surface measurements. The differences between the observed and simulated aerosol radiative forcing resulted from transport errors, relative humidity errors in the upper convective boundary layer that affect aerosol water content, secondary organic aerosols that were not yet included in the model, and uncertainties in the primary particulate emission rates. The current model was run in a predictive mode and demonstrates the challenges of accurately simulating all of the meteorological, chemical, and aerosol parameters over urban to regional scales that can affect aerosol radiative forcing.Citation: Fast, J. D., W. I. Gustafson Jr., R. C. Easter, R. A. Zaveri, J. C. Barnard, E. G. Chapman, G. A. Grell, and S. E. Peckham (2006), Evolution of ozone, particulates, and aerosol direct radiative forcing in the vicinity of Houston using a fully coupled meteorology-chemistry-aerosol model,

Aerosol-Radiation Feedback and PM10 Air Concentrations Over Poland

“…For the INDIR simulation, generally a decrease is observed by -0.17 -1.0 lg m -3 in comparison to DIR but locally in central Poland an increase appears. Partially, it could be explained by liquid phase aerosols formation, as suggested in FORKEL et al (2012). In the case of daily values, differences in PM 10 concentration between DIR and BASE reach 14.0 lg m -3 and are positive for about 80 % of the domain.…”

“…Despite the relatively coarse resolution, the results of ZHANG et al (2010) indicated the potential importance of the aerosol feedbacks on a regional scale, even at a time scale of a month. Similar studies on feedback effects have been undertaken for Europe by FORKEL et al (2012), where the WRF-Chem model was implemented at a resolution of 22.5 9 22.5 km. This work has shown that over the European continent, many of the spatial changes in meteorological parameters and pollutants due to aerosol effects are not only a general feature but also a result of the prevailing meteorological situation.…”

Impacts of aerosol-radiation feedback on local air quality during a severe haze episode in Nanjing megacity, eastern China

“…It is worth noting that the inclusion of aerosol feedbacks is important for better prediction of radiation fields, which reduces the model bias from 84.3 to 15.9 W m −2 , though a slight overestimation still exists. Similarly, Fast et al (2006) also found an overestimation of predicted shortwave radiation by up to 40 W m −2 for the Houston area when the impact of aerosols on solar radiation was neglected.…”

Impacts of weather conditions modified by urban expansion on surface ozone: Comparison between the Pearl River Delta and Yangtze River Delta regions

“…This numerical model system is "online" in the sense that all processes affecting the gas phase and the aerosol species are calculated concurrently with the meteorological dynamics. It has been successfully applied for regional air quality studies (Fast et al, 2006). Different physics and chemistry options in the WRF-Chem can be used.…”