Optical properties of humic-like substances (HULIS) in biomass-burning aerosols
Hoffer, A. ; Gelencsér, A. ; Guyon, P. ; Kiss, G. ; Schmid, O. ; Frank, G. P. LU
; Artaxo, P.
and Andreae, M. O.
(2006)
In Atmospheric Chemistry and Physics
6(11).
p.3563-3570
- Abstract
We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass-burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure" calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was... (More)
We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass-burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure" calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65-0.0019i and 1.69-0.0016i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS at 532 nm was found to be quite low (0.031 and 0.029 m2 g-1 for the day and night samples, respectively). However, due to the high absorption Angstrom exponent (6-7) of HULIS, the specific absorption increases substantially towards shorter wavelengths (∼2-3 m2 g -1 at 300 nm), causing a relatively high (up to 50%) contribution to the light absorption of our Amazonian aerosol at 300 nm. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4-8.6%) are obtained, but those are still not negligible.
(Less)
- author
- Hoffer, A.
; Gelencsér, A.
; Guyon, P.
; Kiss, G.
; Schmid, O.
; Frank, G. P.
LU
; Artaxo, P.
and Andreae, M. O.
- publishing date
- 2006
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Atmospheric Chemistry and Physics
- volume
- 6
- issue
- 11
- pages
- 8 pages
- publisher
- Copernicus GmbH
- external identifiers
-
- scopus:33748292801
- ISSN
- 1680-7316
- DOI
- 10.5194/acp-6-3563-2006
- language
- English
- LU publication?
- no
- id
- 9fe63ba6-4218-4fd5-86cb-a5f80204bd22
- date added to LUP
- 2020-11-09 15:00:26
- date last changed
- 2022-05-24 02:14:25
@article{9fe63ba6-4218-4fd5-86cb-a5f80204bd22,
abstract = {{<p>We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass-burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure" calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65-0.0019i and 1.69-0.0016i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS at 532 nm was found to be quite low (0.031 and 0.029 m<sup>2</sup> g<sup>-1</sup> for the day and night samples, respectively). However, due to the high absorption Angstrom exponent (6-7) of HULIS, the specific absorption increases substantially towards shorter wavelengths (∼2-3 m<sup>2</sup> g <sup>-1</sup> at 300 nm), causing a relatively high (up to 50%) contribution to the light absorption of our Amazonian aerosol at 300 nm. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4-8.6%) are obtained, but those are still not negligible.</p>}},
author = {{Hoffer, A. and Gelencsér, A. and Guyon, P. and Kiss, G. and Schmid, O. and Frank, G. P. and Artaxo, P. and Andreae, M. O.}},
issn = {{1680-7316}},
language = {{eng}},
number = {{11}},
pages = {{3563--3570}},
publisher = {{Copernicus GmbH}},
series = {{Atmospheric Chemistry and Physics}},
title = {{Optical properties of humic-like substances (HULIS) in biomass-burning aerosols}},
url = {{http://dx.doi.org/10.5194/acp-6-3563-2006}},
doi = {{10.5194/acp-6-3563-2006}},
volume = {{6}},
year = {{2006}},
}