Premium
Characterization of fresh and aged biomass burning events using multiwavelength Raman lidar and mass spectrometry
Author(s) -
Nicolae D.,
Nemuc A.,
Müller D.,
Talianu C.,
Vasilescu J.,
Belegante L.,
Kolgotin A.
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50324
Subject(s) - aerosol , lidar , angstrom exponent , single scattering albedo , environmental science , atmospheric sciences , mass concentration (chemistry) , effective radius , particle (ecology) , mass spectrometry , radius , materials science , meteorology , chemistry , physics , optics , astrophysics , geology , chromatography , oceanography , computer security , galaxy , computer science
This paper focuses on optical and microphysical properties of long‐range transported biomass burning (BB) aerosols and their variation with atmospheric evolution (ageing), as observed by a multiwavelength Raman lidar, part of EARLINET (European Aerosol LIdar NETwork). Chemical analysis of the atmospheric aerosol was done using a colocated aerosol mass spectrometer (AMS). One relevant optical parameter for the ageing process is the Ångström exponent. In our study, we find that it decreases from 2 for fresh to 1.4–0.5 for aged smoke particles. The ratio of lidar (extinction‐to‐backscatter) ratios (LR 532 /LR 355 ) changes rapidly from values <1 for fresh to >1 for aged particles. The imaginary part of the refractive index is the most sensitive microphysical parameter. It decreases sharply from 0.05 to less than 0.01 for fresh and aged smoke particles, respectively. Single‐scattering albedo (SSA) varies from 0.74 to 0.98 depending on aerosol age and source. The AMS was used to measure the marker ions of wood‐burning particles during 2 days of measurements when the meteorological conditions favored the downward mixing of aerosols from lofted layers. Particle size distribution and particle effective radius from both AMS and lidar are similar, i.e., particle effective radii were approximately 0.27 µm for fresh BB aerosol particles. Microphysical aerosol properties from inversion of the lidar data agree with similar studies carried out in different regions on the globe. Our study shows that the Ångström exponent LR 532 /LR 355 and the imaginary part of the refractive index can be used to clearly distinguish between fresh and aged smoke particles.