Evaluation of operational online-coupled regional air quality models over Europe and North America in the context of AQMEII phase 2. Part II: Particulate matter

Abstract

The second phase of the Air Quality Model Evaluation International Initiative (AQMEII) brought together sixteen modeling groups from Europe and North America, running eight operational online-coupled air quality models over Europe and North America on common emissions and boundary conditions. With the advent of online-coupled models providing new capability to quantify the effects of feedback processes, the main aim of this study is to compare the response of coupled air quality models to simulate levels of O 3 over the two continental regions. The simulated annual, seasonal, continental and sub-regional ozone surface concentrations and vertical profiles for the year 2010 have been evaluated against a large observational database from different measurement networks operating in Europe and North America. Results show a general model underestimation of the annual surface ozone levels over both continents reaching up to 18% over Europe and 22% over North America. The observed temporal variations are successfully reproduced with correlation coefficients larger than 0.8. Results clearly show that the simulated levels highly depend on the meteorological and chemical configurations used in the models, even within the same modeling system. The seasonal and sub-regional analyses show the models' tendency to overestimate surface ozone in all regions during autumn and underestimate in winter. Boundary conditions strongly influence ozone predictions especially during winter and autumn, whereas during summer local production dominates over regional transport. Daily maximum 8-hour averaged surface ozone levels below 50-60 g m-3 are overestimated by all models over both continents while levels over 120-140 g m-3 are underestimated, suggesting that models have a tendency to severely under-predict high O 3 values that are of concern for air quality forecast and control policy applications.

A parameterization of the heterogeneous hydrolysis of N<sub>2</sub>O<sub>5</sub> for mass-based aerosol models: improvement of particulate nitrate prediction

“…This is comparable with other models (Im et al, 2015). However, short periods with strong overestimations of [NO − 3 ] were also observed in previous New scheme (this study) 50 % * * Suggested by Sintermann et al (2012), Backes et al (2016), and Chen et al (2016b). studies.…”

“…In previous evaluation studies (Im et al, 2015;Wolke et al, 2012), the COSMO-MUSCAT model predicted particulate nitrate mass concentrations ([NO − 3 ]) in fair agreement with the measurements, with an overestimation in the range of 50 % on long-term average. This is comparable with other models (Im et al, 2015).…”

Air quality modelling in the summer over the eastern Mediterranean using WRF-Chem: chemistry and aerosol mechanism intercomparison

“…During the second phase of the Air Quality Model Evaluation International Initiative (AQMEII), the nine working groups using the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) operationally reported an overall underestimation of the annual surface ozone (O 3 ) levels reaching up to 18 % over Europe and 22 % over North America (Im et al, 2015b) with autumn overestimation and winter underestimation. The meteorological and chemical configurations of the different groups were found to have a considerable effect on simulated O 3 levels.…”

Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region

“…Several studies of available observations show that the PM 10 European Union air quality standard (50 µg m −3 , daily average) is exceeded at many locations around the basin because of a combination of mineral dust and anthropogenic pollutants from local sources (Gerasopoulos et al, 2006;Gobbi et al, 2007;Koçak et al, 2007;Rodriguez et al, 2007;Kaskaoutis et al, 2008). Mineral dust outbreaks, although transported through the Mediterranean sea during all seasons, are more frequent in spring and summer, where dust plumes are transported through the Atlantic and reach mainly and regularly the western part of the region (Moulin et al, 1998;Israelevich et al, 2012;Salvador et al, 2014;Ripoll et al, 2015). In summer, mineral dust aerosols are also observed over central Europe (Israelevich et al, 2012;Salvador et al, 2014).…”