Remote Sensing of Particle Matter Using Meris

The MERIS aerosol remote sensing over ocean is available and over land has been improved for a better spatial coverage. Air quality monitoring of the particles is based on in situ measurements of PM10 and PM2.5 which are respectively the density of particles of diameter lesser than 10 μm, lesser than 2.5 μm, at the surface. In order to promote the use of Earth Observation, we would like to convert the satellite aerosol product into PM first based on different assumptions: particle density and vertical distribution mainly. Because of the spatial homogeneity of the aerosols, a PM product can be developing on level-3. Preliminary to such a product, we did analyze the quality of the level-2 product. Roughness of the terrain implies artificial variations of the aerosol optical thickness (AOT). Vicinity of clouds increases artificially the AOT as well as the presence of cirrus clouds. The potentiality of a method based on the oxygen absorption is demonstrated to flag cirrus clouds. Having a level-3 can be as well a useful tool to have a global view in the interpretation of local dust events. A first attempt to calibrate the satellite imagery using the in-situ PM measurements is reported. With the frame of a European project, we generated, over an area centered on Lille (50’36° N, 3’08 E, North of France), a representative data base with SeaWiFS, and the PM data collected by the regional air quality network. Correlations between PM and AOT are not straightforward and that suggest the need of auxiliary data to improve the correlation.