Study of a photochemical episode over the Grenoble area using a mesoscale model and intensive measurements

The Grenoble metropolitan area located in the French Alps with more than 400 thousand inhabitants suffers from periods of high ozone (O3) concns. in summertime. Grenoble is moreover located in the Y shaped convergence of three deep valleys with surrounding mountains up to 3,000 m above sea level (asl) leading to a very complex wind pattern. During summer 1999, a major field campaign GRENOble PHOTochem. (GRENOPHOT) involving std. ground based stations, LIDAR, aircraft, DOAS, microwave windprofilers was carried out in order to obtain the measurements needed for model validation. The air quality model METeorol. PHOtochem. MODel (METPHOMOD) developed at the University of Bern and at the Swiss Federal Institute of Technol. at Lausanne, was used to investigate the dynamic characteristics of air pollution in the Grenoble area during GRENOPHOT. The lumped chem. mechanism Regional Atm. Chem. Mechanism (RACM) was used for the calcn. A one-way nesting technique was used in which the large grid is a squared 198 km one with a grid resoln. of 6 * 6 km and the small one is a rectangular 78 * 68 km with a grid resoln. of 2 * 2 km. There are 24 vertical levels up to 8,000 m asl. The meteorol. and chem. simulations were validated with ground and vertical profiles measurements performed during the Intensive Observation Period (IOP) July, 25-27, when the O3 concns. reached up to 95 ppb. Both the spatial as well as the temporal variabilities of the simulated O3 concns. correspond reasonably well to the measured values. They caught the O3 plume south of Grenoble. The model results indicate a lower Planet Boundary Layer (PBL) height than the LIDAR obsd. The PBL calcd. by the model is about 2,100 m, whereas the LIDAR indicates about 2,400 m. The results show that the PBL in mountain terrain is higher than those found over flat terrain. A specific vertical stratification of the atm. at day and night time is obsd. during typical photochem. episodes. Highest O3 values appear in the south at 25 km downwind the city center, and the results show that about 32 ppb of fresh O3 are generated in the Grenoble plume.

Published in:
Pollution atmosphérique, 174
Copyright 2003 ACS
AN 2002:684237
CAN 137:374055
Air Pollution and Industrial Hygiene
Laboratoire de Pollution de l'Air et des Sols (LPAS),Ecole Polytechnique Federale de Lausanne (EPFL),Lausanne,Switz. FIELD URL:
written in French.
Air pollution (photochem.; study of photochem. episode over Grenoble, France using mesoscale model and measurements); Environmental modeling (study of photochem. episode over Grenoble, France using mesoscale model and measurements)
1) National Research Council; Rethinking the ozone problem in urban and regional air pollution 1991|2) Anquetin, S; Pollution a l'echelle locale et regionale; Cachan 1993, 99|3) Perego, S; Meteorol Atmos Phys 1999, 70, 43|4) Stockwell, W; J Geophys Res 1997, 102, 25847|5) Jimenez, R; Proceedings of A&WMA 93rd Annual Conference 2000|6) Quaglia, P; Analusis, European Journal Analytical Chemistry 1999, 27, 305|7) Quaglia, P; Eurotrac Symposium 2000 2000|8) Apsley, D; Boundary-Layer Meteor 1997, 83, 75|9) Paltridge, G; Development in atmospheric science 1976, 5|10) Piekle, R; Mesoscale meteorological modelling 1984|11) Deardorff's, J; J Geophys Res 1978, 83, 1889|12) US Geological Survey; Digital elevation models, data user guide 5 1993|13) Brown, J; Photogrammetric Engineering and Remote Sensing 1999, 65, 1069|14) Bouscaren, R; Realisation d'un inventaire d'emissions simplifiees pour la ville de Grenoble (1 heure-1 km2). Convention no 98338001 1999, 392|15) Friedrich, R; Anthropogenic emissions of Volatile Organic Compounds in reactiv hydrocarbons in atmosphere 1999, 1|16) Majewski, D; ECMWF Seminar on numerical methods in atmospheric models 1999, 2, 147|17) Beyrich, F; Atmos Environ 1996, 30, 1271|18) Martilli, A; Accepted by Boundary-Layer Meteorology 2002|19) Kunzle, T; Boundary-Layer Meteorology 1994, 69, 221

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