Assessment of vertically-resolved PM10 from mobile lidar observations 1Laboratoire de Météorologie Dynamique, Ecole Polytechnique, 91128 Palaiseau, France
2Laboratoire des Sciences du Climat et de l'Environnement, Laboratoire mixte CEA-CNRS-UVSQ, CEA Saclay, 91191 Gif-sur-Yvette, France
*now at: Laboratoire Atmosphères, Milieux et Observations Spatiales, Laboratoire mixte CNRS-UVSQ-UPMC, Université Paris 6, 75252 Paris, France
Received: 28 Apr 2009 – Published in Atmos. Chem. Phys. Discuss.: 18 Jun 2009 Abstract. We investigate in this study the vertical PM10 distributions from mobile
measurements carried out from locations along the Paris Peripherique (highly
trafficked beltway around Paris), examine distinctions in terms of aerosol
concentrations between the outlying regions of Paris and the inner city and
eventually discuss the influence of aerosol sources, meteorology, and
dynamics on the retrieved PM10 distributions. To achieve these purposes, we
combine in situ surface measurements with active remote sensing observations
obtained from a great number of research programs in Paris area since 1999.
Two approaches, devoted to the conversion of vertical profiles of
lidar-derived extinction coefficients into PM10, have been set up. A very
good agreement is found between the theoretical and empirical methods with a
discrepancy of 3%. Hence, specific extinction cross-sections at 355 nm
are provided with a reasonable relative uncertainty lower than 12% for
urban (4.5 m2 g−1) and periurban (5.9 m2 g−1) aersols, lower than
26% for rural (7.1 m2 g−1) aerosols, biomass burning (2.6 m2 g−1)
and dust (1.1 m2 g−1) aerosols The high spatial and temporal resolutions
of the mobile lidar (respectively 1.5 m and 1 min) enable to follow the
spatiotemporal variability of various layers trapping aerosols in the
troposphere. Appropriate specific extinction cross-sections are applied in
each layer detected in the vertical heterogeneities from the lidar profiles.
The standard deviation (rms) between lidar-derived PM10 at 200 m above
ground and surface network stations measurements was ~14μg m−3.
This difference is particularly ascribed to a decorrelation of
mass concentrations in the first meters of the boundary layer, as
highlighted through multiangular lidar observations. Lidar signals can be
used to follow mass concentrations with an uncertainty lower than 25%
above urban areas and provide useful information on PM10 peak forecasting
that affect air quality.
Revised: 22 Oct 2009 – Accepted: 30 Oct 2009 – Published: 12 Nov 2009
Citation: Raut, J.-C. and Chazette, P.: Assessment of vertically-resolved PM10 from mobile lidar observations, Atmos. Chem. Phys., 9, 8617-8638, doi:10.5194/acp-9-8617-2009, 2009.