Autor(es):
Preißler, Jana 
; Silva, Ana Maria ; Wagner, Frank ; Nepomuceno Pereira, Sérgio ; Guerrero-Rascado, Juan Luis
Data: 2014
Identificador Persistente: http://hdl.handle.net/10174/11313
Origem: Repositório Científico da Universidade de Évora
Assunto(s): atmospheric aerosols; Raman lidar; forest fires smoke
Descrição
Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength
Raman lidar, are presented.Thetransportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke
particles over the site. Some strong layers aloftwere observedwith particle backscatter and extinction coefficients (at 355 nm) greater
than 5Mm−1 sr−1 and close to 300Mm−1, respectively. The particle intensive optical properties showed features different from the
ones reported for aged smoke, but rather consistent with fresh smoke.The ˚Angstr¨om 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 um, 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.
