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Springtime major pollution events by aerosol over Paris Area: From a case study to a multiannual analysis
Author(s) -
Chazette Patrick,
Royer Philippe
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd026713
Subject(s) - lidar , environmental science , aerosol , pollution , aeronet , population , remote sensing , meteorology , mineral dust , atmospheric sciences , geography , geology , ecology , demography , sociology , biology
A study of the intense spring pollution events occurring between 2007 and 2016 on the Paris Area is presented using ground‐based and spaceborne measurements. Emphasis is placed on 2011 where data included ground‐based lidar measurements. This last period corresponds with the highest regional pollution levels of the past decade. The information threshold (daily average of (mass concentration of particles with aerodynamic diameter less than 10 μm) PM 10 > 50 μg m −3 ) was exceeded 16 times, while the alert threshold (daily average of PM 10 > 80 μg m −3 ) was exceeded twice. The information (alert) threshold exists to protect the most fragile people (the entire population). Ground‐based and spaceborne measurements demonstrate the benefit of their synergy as each is representative of specific space and time scales. The operational products of the spaceborne instruments Cloud‐Aerosol LIdar with Orthogonal Polarization (CALIOP) and the Moderate Resolution Imaging Spectroradiometer are used. For 2011, CALIOP vertical profiles are inversed to assess the backscatter to extinction ratio, which is then successfully compared with similar results derived from the CALIOP operational products, a ground‐based lidar and Sun photometers. The aerosols are identified to be polluted continental and polluted dust aerosols following the criteria used for the inversion of the CALIOP profiles. Aerosol typing is consistent between the ground‐based and spaceborne lidars, demonstrating the importance of CALIOP for other years where the ground‐based lidar was not in operation. The main pollution sources responsible for the spring aerosol pollution, occurring during anticyclonic meteorological conditions, are identified as coming from Western Europe: Benelux, Rhine‐Ruhr area, and the Lorraine area.