APPORTIONMENT OF LIGHT-SCATTERING AND HYGROSCOPIC GROWTH TO AEROSOL COMPOSITION

Citation
L. Mcinnes et al., APPORTIONMENT OF LIGHT-SCATTERING AND HYGROSCOPIC GROWTH TO AEROSOL COMPOSITION, Geophysical research letters, 25(4), 1998, pp. 513-516
Citations number
16
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary
ISSN journal
0094-8276
Volume
25
Issue
4
Year of publication
1998
Pages
513 - 516
Database
ISI
SICI code
0094-8276(1998)25:4<513:AOLAHG>2.0.ZU;2-2
Abstract
During a recent campaign at the NOAA CMDL monitoring station on Sable Island, Canada (43.93 degrees N, 60.01 degrees W) a dual-nephelometer humidigraph measured the hygroscopic growth factor of aerosol scatteri ng, f(RH)(sigma(sp)), one of the key parameters necessary for estimati ng short-wave aerosol radiative forcing. Measurements revealed less gr owth anthropogenically influenced aerosols than for marine, f(RH)(sigm a(sp)) of 1.7 +/- 0.1 vs. 2.7 +/- 0.4, where f(RH)(sigma(sp)) = sigma( sp(85%))/sigma(sp(40%)). combined measurement-modeling approach was us ed to estimate sigma(sp) and its RH-dependence, based on the measured particle size distribution and composition. The model suggested that d ifferences in the particle size distribution, assuming the same aeroso l composition, could not explain the observed differences in f(RH)(sig ma(sp)). We have confirmed with individual particle analysis, that aer osol composition was indeed responsible for the difference in f(RH)(si gma(sp)). As well, the scattering contribution of organic carbon for t he influenced case is at least as much as sulfate aerosol.