A multi-model assessment for the 2006 and 2010 simulations under the Air Quality Model Evaluation International Initiative (AQMEII) phase 2 over North America: Part I. Indicators of the sensitivity of O3 and PM2.5 formation regimes

Application of WRF/Chem over North America under the AQMEII Phase 2 – Part 2: Evaluation of 2010 application and responses of air quality and meteorology–chemistry interactions to changes in emissions and meteorology from 2006 to 2010

“…Increased PM 2.5 concentrations in JFD and MAM in the Midwest are due to surface temperature decreases, which are dominating in this region (Stoeckenius et al, 2015). This in turn leads to increased particle nitrate concentrations (Campbell et al, 2014). However, there are differences in magnitudes, especially for SWDOWN.…”

“…S3 Table 1 in Yahya et al (2014). (Chen, 2007). Pleim and Gilliam (2009) A smaller overall averaged NMB but a larger NME may indicate compensation of over-and underpredictions leading to a small bias, but the magnitude of the differences are reflected in the NME values.…”

A comparison between 2010 and 2006 air quality and meteorological conditions, and emissions and boundary conditions used in simulations of the AQMEII-2 North American domain

“…Several participants in the AQMEII-2 collaboration who are applying coupled models to the North American domain are comparing model results for two very different years: 2006 and 2010 (Campbell et al, 2015;Hogrefe et al, 2015;Wang et al, 2015). While the key differences of interest between these two years from a modeling perspective are the predicted air quality impacts of the large reductions in emissions of NO x (21%) and SO 2 (36%) which occurred mostly in the eastern U.S. and the lower emissions from wildfires in the western U.S., meteorological conditions and model boundary conditions (BCs) also differed significantly between these two years.…”

“…Moreover, as discussed in the next section, year specific emission information for 2006 and 2010 was available only for the U.S., therefore the analysis of emissions and observed air quality is limited to the U.S. Comparisons of observed meteorological and air quality conditions with model predictions are not included in this paper but are the subject of several companion papers (Campbell et al, 2015;Hogrefe et al, 2015;Wang et al, 2015); the current study provides context for these studies.…”

An alternative way to evaluate chemistry-transport model variability

“…Complementary to the definition of performance indicators to be used, Simon et al (2012) used these indicators to compile photochemical model performance for a large set of data over several years of simulation. This kind of evaluation may also be done in dedicated projects, such as the recent AQMEII (Air Quality Model Evaluation International Initiative), comparing chemistry-transport models running both in Europe and North America (Vautard et al, 2012;Campbell et al, 2015); the EURODELTA project ; and the EMEP (European Monitoring and Evaluation Programme) context in the framework of the United Nations Convention on Long-range Transboundary Air Pollution (Prank et al, 2016). Using comparisons between observations and model outputs, some studies proposed methodologies to decompose the statistical scores in order to estimate the main source of errors (Solazzo and Galmarini, 2016).…”