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| Titel |
Retrieval of sulfur dioxide from a ground-based thermal infrared imaging camera |
| VerfasserIn |
A. J. Prata, C. Bernardo |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 9 ; Nr. 7, no. 9 (2014-09-03), S.2807-2828 |
| Datensatznummer |
250115889
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| Publikation (Nr.) |
 copernicus.org/amt-7-2807-2014.pdf |
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| Zusammenfassung |
| Recent advances in uncooled detector technology now offer the possibility of
using relatively inexpensive thermal (7 to 14 μm) imaging devices
as tools for studying and quantifying the behaviour of hazardous gases and
particulates in atmospheric plumes. An experimental fast-sampling (60 Hz)
ground-based uncooled thermal imager (Cyclops), operating with four spectral
channels at central wavelengths of 8.6, 10, 11 and 12 μm and one
broadband channel (7–14 μm) has been tested at several volcanoes
and at an industrial site, where SO2 was a major constituent of the
plumes. This paper presents new algorithms, which include atmospheric
corrections to the data and better calibrations to show that SO2 slant
column density can be reliably detected and quantified. Our results indicate
that it is relatively easy to identify and discriminate SO2 in
plumes, but more challenging to quantify the column densities. A full
description of the retrieval algorithms, illustrative results and a detailed
error analysis are provided. The noise-equivalent temperature difference
(NEΔT) of the spectral channels, a fundamental measure of the quality
of the measurements, lies between 0.4 and 0.8 K, resulting in slant column
density errors of 20%. Frame averaging and improved NEΔT's can
reduce this error to less than 10%, making a stand-off, day or night
operation of an instrument of this type very practical for both monitoring
industrial SO2 emissions and for SO2 column densities and emission
measurements at active volcanoes. The imaging camera system may also be used
to study thermal radiation from meteorological clouds and the
atmosphere. |
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