Aerosol Extinction Spectra Research Articles

On the relation between haze layer and air mass aerosol at an urban location — case studies

Aerosol extinction spectra of the lowest part of the urban boundary layer at Leipzig measured by means of sunphotometers in the wavelength range between 0.36 μm and 1.05 μm are presented. The temporal behaviour of these spectra is compared with that of relevant atmospheric turbidity parameters. Special attention is paid to the analysis of atmospheric aerosol optical thickness spectra. It is shown that, concerning aerosol properties, the ageing of an air mass caused by urban activities is identical with an increase of aerosol optical thickness, especially in the short-wavelength-range. This fact could be attributed to the convective rise of, primarily, small aerosol particles ( r < 0.3 μm) being emitted by anthropogenic sources near the ground. This process also seems to be responsible for a vertical aerosol stratification within the haze layer. It was found that in the case of turbulent mixing the optical state of the around layer is mainly determined by accumulation and coarse mode particles, whereas the upper layers contain a large amount of fine particles.

Frequency-dependent optical constants of water ice obtained directly from aerosol extinction spectra

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFrequency-dependent optical constants of water ice obtained directly from aerosol extinction spectraM. L. Clapp, D. R. Worsnop, and R. E. MillerCite this: J. Phys. Chem. 1995, 99, 17, 6317–6326Publication Date (Print):April 1, 1995Publication History Published online1 May 2002Published inissue 1 April 1995https://doi.org/10.1021/j100017a010RIGHTS & PERMISSIONSArticle Views445Altmetric-Citations129LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts

Infrared extinction spectra of some common liquid aerosols

Infrared extinction spectra in the 3-5-microm and 7-13-microm atmospheric window regions have been obtained for smokes of petroleum oil, sulfuric acid, and phosphoric acid of varying droplet concentration and for water fogs. Spectra were also obtained at 0.36-2.35microm for petroleum oil and sulfuric acid smokes. Experimental results were compared, for sulfuric acid and water aerosols, to calculated values obtained from the Mie theory. Agreement was as good as +/-10%. When absorbing smoke droplets are small compared to wavelength, very useful approximations apply, and droplet clouds may be spectrally simulated by thin liquid films. In such cases, the imaginary component of refractive index may be approximated directly from aerosol spectra. At 12.5-microm wavelength, water fog extinction is nearly independent of droplet size distribution, suggesting a simple scheme for measurement of total liquid water content of an optical path.