Dynamic evaluation of a multi-year model simulation of particulate matter concentrations over Europe

oleh: È. Lecœur, C. Seigneur

Format: Article
Diterbitkan: Copernicus Publications 2013-04-01

Deskripsi

A 9 yr air quality simulation is conducted from 2000 to 2008 over Europe using the Polyphemus/Polair3D chemical-transport model (CTM) and then evaluated against the measurements of the European Monitoring and Evaluation Programme (EMEP). <br><br> The spatial distribution of PM<sub>2.5</sub> over Europe shows high concentrations over northern Italy (36 μg m<sup>−3</sup>) and some areas of Eastern Europe, France, and Benelux, and low concentrations over Scandinavia, Spain, and the easternmost part of Europe. PM<sub>2.5</sub> composition differs among regions. <br><br> The operational evaluation shows satisfactory model performance for ozone (O<sub>3</sub>). PM<sub>2.5</sub>, PM<sub>10</sub>, and sulfate (SO<sub>4</sub><sup>=</sup>) meet the performance goal of Boylan and Russell (2006). Nitrate (NO<sub>3</sub><sup>&minus;</sup>) and ammonium (NH<sub>4</sub><sup>+</sup>) are overestimated, although NH<sub>4</sub><sup>+</sup> meets the performance criterion. The correlation coefficients between simulated and observed data are 63% for O<sub>3</sub>, 57% for PM<sub>10</sub>, 59% for PM<sub>2.5</sub>, 57% for SO<sub>4</sub><sup>=</sup>, 42% for NO<sub>3</sub><sup>&minus;</sup>, and 58% for NH<sub>4</sub><sup>+</sup>. The comparison with other recent 1 yr model simulations shows that all models overestimate nitrate. The performance of PM<sub>2.5</sub>, sulfate, and ammonium is comparable to that of the other models. <br><br> The dynamic evaluation shows that the response of PM<sub>2.5</sub> to changes in meteorology differs depending on location and the meteorological variable considered. Wind speed and precipitation show a strong negative day-to-day correlation with PM<sub>2.5</sub> and its components (except for sea salt, which shows a positive correlation), which tends towards 0 as the day lag increases. On the other hand, the correlation coefficient is near constant for temperature, for any day lag and PM<sub>2.5</sub> species, but it may be positive or negative depending on the species and, for sulfate, depending on the location. The effects of precipitation and wind speed on PM<sub>2.5</sub> and its components are better reproduced by the model than the effects of temperature. This is mainly due to the fact that temperature has different effects on the PM<sub>2.5</sub> components, unlike precipitation and wind speed, which impact most of the PM<sub>2.5</sub> components in the same way. <br><br> These results suggest that state-of-the-science air quality models reproduce satisfactorily the effect of meteorology on PM<sub>2.5</sub> and therefore are suitable to investigate the effects of climate change on particulate air quality, although uncertainties remain concerning semivolatile PM<sub>2.5</sub> components.