Please use this identifier to cite or link to this item:

Title: Atmospheric Visibility and Angström Exponent Measurements through Digital Photography
Authors: Carretas, Filipe
Wagner, Frank
Janeiro, Fernando M.
Keywords: Digital photography
Atmospheric visibility measurements
Angström exponent
Lambert–Beer law
Issue Date: Mar-2015
Publisher: Elsevier
Abstract: This paper presents a low-cost system for the measurement of atmospheric visibility. The measurement setup is composed by a consumer digital camera which is controlled by a computer. The camera acquires photos of the landscape that include natural dark objects. Then the computer calculates the atmospheric visibility based on the apparent contrast, against the background, of these dark objects through the Lambert–Beer law. Two different approaches are proposed so that the system is able to measure the atmospheric visibility both under normal and low visibility conditions. The use of the three color channels of the camera allows the measurement of the extinction coefficient at different wavelengths along with the Angström exponent which is an important parameter in the classification of atmosphere aerosols. Measurements performed with the developed system are presented and include the atmospheric visibility, the extinction coefficient and the Angström exponent. The results presented correspond to the measurements performed along a week that included a desert dust event. This event dramatically reduced the atmospheric visibility due to the desert dust particles. Angström exponent measurements were performed with another instrument for comparison. Finally, an uncertainty analysis of the measured atmospheric visibility is presented.
Type: article
Appears in Collections:FIS - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica
CEM - Publicações - Artigos em Revistas Internacionais Com Arbitragem Científica

Files in This Item:

File Description SizeFormat
21. Measurement 2015.pdf1.53 MBAdobe PDFView/OpenRestrict Access. You can Request a copy!
FacebookTwitterDeliciousLinkedInDiggGoogle BookmarksMySpaceOrkut
Formato BibTex mendeley Endnote Logotipo do DeGóis 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Dspace Dspace
DSpace Software, version 1.6.2 Copyright © 2002-2008 MIT and Hewlett-Packard - Feedback
UEvora B-On Curriculum DeGois