Characterization of aerosol hygroscopicity using Raman lidar measurements at the EARLINET station of Payerne

• Published in: Atmospheric chemistry and physics 2019-09, Vol.19 (18), p.11651-11668
• Main Authors: Navas-Guzmán, Francisco, Martucci, Giovanni, Collaud Coen, Martine, Granados-Muñoz, María José, Hervo, Maxime, Sicard, Michael, Haefele, Alexander
• Format: Article
• Language: English
• Subjects: Aerosol effects; Aerosol properties; Aerosols; Aerosols atmosfèrics; Altitude; Analysis; Atmosphere; Atmospheric aerosols; Atmospheric models; Atmospheric particulates; Backscatter; Backscattering; Climate; Computer simulation; Contaminació atmosfèrica; Degradació ambiental; Dehydration; Dehydration (Physiology); Desenvolupament humà i sostenible; Dust storms; Earth; Enginyeria de la telecomunicació; Humidity; Hygroscopicity; Intercomparison; Lidar; Lidar measurements; Methods; Mixing ratio; Optical radar; Profiles; Properties; Radiative transfer; Radiocomunicació i exploració electromagnètica; Radiosondes; Relative humidity; Remote sensing; Remote sensing techniques; Sensing techniques; Sensors; Smoke; Smoke particles; Studies; Teledetecció; Telescopes; Troposphere; Water vapor; Water vapour; Wavelength; Àrees temàtiques de la UPC
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-19-11651-2019

This study focuses on the analysis of aerosol hygroscopicity using remote sensing techniques. Continuous observations of aerosol backscatter coefficient (β.sup.aer ), temperature (T) and water vapor mixing ratio (r) have been performed by means of a Raman lidar system at the aerological station of MeteoSwiss at Payerne (Switzerland) since 2008. These measurements allow us to monitor in a continuous way any change in aerosol properties as a function of the relative humidity (RH). These changes can be observed either in time at a constant altitude or in altitude at a constant time. The accuracy and precision of RH measurements from the lidar have been evaluated using the radiosonde (RS) technique as a reference. A total of 172 RS profiles were used in this intercomparison, which revealed a bias smaller than 4 % RH and a standard deviation smaller than 10 % RH between both techniques in the whole (in lower) troposphere at nighttime (at daytime), indicating the good performance of the lidar for characterizing RH. A methodology to identify situations favorable to studying aerosol hygroscopicity has been established, and the aerosol hygroscopicity has been characterized by means of the backscatter enhancement factor (f.sub.β). Two case studies, corresponding to different types of aerosol, are used to illustrate the potential of this methodology.