Abstract
In this paper, the “Expérience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emissions” (ESCOMPTE) program is presented. The ESCOMPTE program is used to produce a relevant set of data for testing and evaluating regional pollution models. It includes high-resolution (in space and time) atmospheric emission inventories and field experiments, and covers an area of 120×120 km, centered over the Marseilles-Berre area in the southeast of France during Summer 2001. This region presents a high occurrence of photochemical pollution events, which result from numerous industrial and urban sources of primary pollutants. From the dynamical characteristics of the area, sea-breeze circulation and channeling effects due to terrain features highly influence the location of the pollutant plumes. ESCOMPTE will provide a highly documented framework for dynamics and chemistry studies. Campaign strategies and experimental set up are described. During the planning phase, existing modeling results helped defining the experimental design. The campaign involved surface measurement networks, remote sensing, ship-borne, balloon-borne, and airplane measurements. Mean standard meteorological parameters and turbulent fluxes, ozone, ozone precursors, photochemically active trace gases, and aerosols were measured. Five intensive observation periods (IOPs) were documented using a wide spectrum of instruments, involving aircraft (7) (one of them equipped with a Doppler lidar, the others for in situ meteorological and chemical measurements), constant volume balloons (33), ozone lidars (5), wind profilers (15 sodars and radars), Doppler scanning lidar (1), radiosonde systems (at 4 locations), instrumented ships (2). In addition to the air quality networks from environmental agencies, 15 supplementary ground stations equipped for chemistry and/or meteorology and/or surface flux measurements, were operational. All instruments were calibrated and compared during a Quality Control/Quality Assurance (QC/QA) week, at the very beginning of the campaign. Fifteen days were intensively documented during five IOPs, referenced as 1, 2a, 2b, 3, and 4. High pollution levels were encountered during sea-breeze conditions observed during IOPs 2b and 3, whereas IOPs 2a and 4 corresponded to moderate wind, and channeled plume regimes. In addition, hourly emissions inventories for all IOPs were established to complete data sets and to finalize the ESCOMPTE database (EDB). Two other projects were associated to ESCOMPTE: urban boundary layer (UBL) and tropospheric water vapor content by GPS tomography (GPS/H 2O). They took advantage of the scientific environment provided by ESCOMPTE.
Highlights
Throughout the past 30 years, the impact of human activity on the atmosphere has been demonstrated, on global and local scales
The overall policy is based on three leading principles: offer easy access to the ESCOMPTE database (EDB) for the ESCOMPTE scientific community leading to scientific publication involving principal investigators (PIs); maintain easy access to the EDB in the future; maximize the use of the EDB in order to evaluate pollution models output
The data set gathered during the ESCOMPTE field phase undoubtedly constitutes a reference against which mesoscale CTMs could be compared in the forthcoming years
Summary
Throughout the past 30 years, the impact of human activity on the atmosphere has been demonstrated, on global and local scales. Preliminary works confirm the important contribution of the regional scale processes on the pollutant concentrations observed at local scale (Pont and Fontan, 2000) This is true for ozone which is dependent on reservoir species likely to be transported over long distances. The data acquired during this program will be used to address the following scientific issues: validate CTMs, understand relationship between emission of pollutants and airborne observed concentration, understand relationship between atmospheric dynamics and pollution level, understand relationship between air temperature and pollution rate, study urban – rural atmosphere interaction, determine aerosol influence on photochemical pollution. The ESCOMPTE data set will be used to improve these models by providing a reaction scheme of photo-oxidants and particle interactions Taking into account these interactions requires simultaneous measurements of gaseous and radical compounds, and of aerosol physical and chemical (organic and inorganic phases) properties. It presents the strategy and the different components of the program, i.e., emission inventory, field experiments, and modeling
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