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Titel |
A compact, fast UV photometer for measurement of ozone from research aircraft |
VerfasserIn |
R. S. Gao, J. Ballard, L. A. Watts, T. D. Thornberry, S. J. Ciciora, R. J. McLaughlin, D. W. Fahey |
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 ; 5, no. 9 ; Nr. 5, no. 9 (2012-09-11), S.2201-2210 |
Datensatznummer |
250003086
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Publikation (Nr.) |
copernicus.org/amt-5-2201-2012.pdf |
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Zusammenfassung |
In situ measurements of atmospheric ozone (O3) are performed routinely
from many research aircraft platforms. The most common technique depends on
the strong absorption of ultraviolet (UV) light by ozone. As atmospheric
science advances to the widespread use of unmanned aircraft systems (UASs),
there is an increasing requirement for minimizing instrument space, weight,
and power while maintaining instrument accuracy, precision and time
response. The design and use of a new, dual-beam, UV photometer instrument
for in situ O3 measurements is described. A polarization
optical-isolator configuration is utilized to fold the UV beam inside the
absorption cells, yielding a 60-cm absorption length with a 30-cm cell. The
instrument has a fast sampling rate (2 Hz at <200 hPa, 1 Hz at 200–500 hPa, and 0.5 Hz at ≥ 500 hPa), high accuracy (3% excluding
operation in the 300–450 hPa range, where the accuracy may be degraded to
about 5%), and excellent precision (1.1 × 1010 O3 molecules
cm−3 at 2 Hz, which corresponds to 3.0 ppb at 200 K and 100 hPa, or
0.41 ppb at 273 K and 1013 hPa). The size (36 l), weight (18 kg), and power
(50–200 W) make the instrument suitable for many UASs and other airborne
platforms. Inlet and exhaust configurations are also described for ambient
sampling in the troposphere and lower stratosphere (1000–50 hPa) that
control the sample flow rate to maximize time response while minimizing loss
of precision due to induced turbulence in the sample cell. In-flight and
laboratory intercomparisons with existing O3 instruments show that
measurement accuracy is maintained in flight. |
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