High Resolution Chemistry Transport Modeling with the On-Line CHIMERE-WRF Model over the French Alps—Analysis of a Feedback of Surface Particulate Matter Concentrations on Mountain Meteorology

Abstract

Air pollution is of major concern throughout the world and the use of modeling tools to analyze and forecast the pollutant concentrations in complex orographic areas remains challenging. This work proposes an exhaustive framework to analyze the ability of models to simulate the air quality over the French Alps up to 1.2 km resolution over Grenoble and the Arve Valley. The on-line coupled suite of models CHIMERE-WRF is used in its recent version to analyze a 1 month episode in November–December 2013. As expected, an improved resolution increases the concentrations close to the emission areas and reduced the negative bias for Particulate Matter that is the usual weakness of air quality models. However, the nitrate concentrations seem overestimated with at the same time an overestimation of surface temperature in the morning by WRF. Different WRF settings found in the literature are tested to improve the results, particularly the ability of the meteorological model to simulate the strong thermal inversions in the morning. Wood burning is one of the main contributor of air pollution during the period ranging from 80 to 90% of the Organic Matter. The activation of the on-line coupling has a moderate impact on the background concentrations but surprisingly a change of Particulate Matter (PM) concentrations in the valley will affect more the meteorology nearby high altitude areas than in the valley. This phenomenon is the result of a chain of processes involving the radiative effects and the water vapor column gradients in complex orographic areas. At last, the model confirms that the surrounding glaciers are largely impacted by long range transport of desert dust. However, in wintertime some outbreaks of anthropogenic pollution from the valley when the synoptic situation changes can be advected up to the nearby high altitude areas, then deposited.

Disparities in particulate matter (PM<sub>10</sub>) origins and oxidative potential at a city scale (Grenoble, France) – Part 2: Sources of PM<sub>10</sub> oxidative potential using multiple linear regression analysis and the predictive applicability of multilayer perceptron neural network analysis

“…The three main components of MLP are (1) the input layer, (2) the hidden layer, and (3) the output layer. Generally, the MLP consists of interconnected layers of artificial neurons that form a network using a set of input data and draws it onto a set of output data, which are then used to further train the neural network through a back-propagation process (Bishop, 1995;Fontes et al, 2014;Kim and Gilley, 2008). In this study, the neural network architecture was limited to a one hidden layer design to demonstrate the applicability of non-linear models, even only with a rudimentary architecture, and to compare its predictive capability against that of MLR.…”

The 2017 Mega-Fires in Central Chile: Impacts on Regional Atmospheric Composition and Meteorology Assessed from Satellite Data and Chemistry-Transport Modeling

“…CHIMERE v2020r1 is used, in fully coupled mode, integrating aerosols direct and indirect effects. CHIMERE is a Eulerian 3-dimensional regional Chemistry-Transport Model, able to reproduce gas-phase chemistry, aerosols formation, transport and deposition [25,38]. The v2020r1 version used in this work also provides a full coupling with the Weather Research and Forecasting (WRF) mesoscale numerical weather model from the US National Center for Atmospheric Research [39].…”

Overview of the French Operational Network for In Situ Observation of PM Chemical Composition and Sources in Urban Environments (CARA Program)

“…The oldest ones-namely in Bordeaux, Lyon, Grenoble, Rouen, Strasbourg, and Revinhave been collecting PM 10 filter samples for more than 10 years. Here, results obtained from this dense observation network are supplemented by complementary results acquired during a specific pluriannual research program focusing on air pollution sources and mechanisms in the Arve Valley of the French Alps (DECOMBIO, [14,15]). Data collected at the remote regional background site of the long-term Environmental Observatory (OPE, [16,17])-maintained by the agence nationale pour la gestion des déchets radioactifs (ANDRA)-has also been added for purposes of comparison with results from urban environments.…”

“…Figure15. Contributions of the six factors obtained from the PMF analysis conducted for the urban traffic-oriented station of Fort-de-France (Renéville), out of and during PM10 daily threshold exceedances, which could be investigated for 2018.…”