Forest fire smoke layers observed in the free troposphere over portugal with a multiwavelength raman lidar: optical and microphysical properties
Nepomuceno Pereira, Sérgio Preißler, Jana Guerrero-Rascado, Juan Luis Silva, Ana Maria Wagner, Frank
Nepomuceno Pereira, Sérgio
Preißler, Jana
Guerrero-Rascado, Juan Luis
Silva, Ana Maria
Wagner, Frank
Citations
Altmetric:
Publication Date
2014-01-01
Type
journal article
Downloads
Citation
Nepomuceno Pereira, Sérgio; Preißler, Jana; Guerrero-Rascado, Juan Luis; Silva, Ana Maria; Wagner, Frank (2014). Forest fire smoke layers observed in the free troposphere over portugal with a multiwavelength raman lidar: optical and microphysical properties. The Scientific World Journal ,
Abstract
Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength Raman lidar, are presented. The transportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke particles over the site. Some strong layers aloft were observed with particle backscatter and extinction coefficients (at 355 nm) greater than 5 Mm(-1) sr(-1) and close to 300 Mm(-1), respectively. The particle intensive optical properties showed features different from the ones reported for aged smoke, but rather consistent with fresh smoke. The Angstrom exponents were generally high, mainly above 1.4, indicating a dominating accumulation mode. Weak depolarization values, as shown by the small depolarization ratio of 5% or lower, were measured. Furthermore, the lidar ratio presented no clear wavelength dependency. The inversion of the lidar signals provided a set of microphysical properties including particle effective radius below 0.2 mu m, which is less than values previously observed for aged smoke particles. Real and imaginary parts of refractive index of about 1.5-1.6 and 0.02i, respectively, were derived. The single scattering albedo was in the range between 0.85 and 0.93; these last two quantities indicate the nonnegligible absorbing characteristics of the observed particles.
Funder
Publisher
Hindawi Limited