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| Titel |
Column water vapor determination in night period with a lunar photometer prototype |
| VerfasserIn |
A. Barreto, E. Cuevas, B. Damiri, P. M. Romero, F. Almansa |
| 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 ; 6, no. 8 ; Nr. 6, no. 8 (2013-08-29), S.2159-2167 |
| Datensatznummer |
250085046
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| Publikation (Nr.) |
 copernicus.org/amt-6-2159-2013.pdf |
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| Zusammenfassung |
In this paper we present the preliminary results of atmospheric
column-integrated precipitable water vapor (PWV) obtained with a new Lunar Cimel
photometer (LC) at the high mountain Izaña Observatory in the period
July–August 2011. We have compared quasi-simultaneous nocturnal PWV from LC with PWV
from a Global Positioning System (GPS) receiver and nighttime
radiosondes (RS92). LC data have been calibrated using the Lunar
Langley method (LLM). We complemented this comparative study using
quasi-simultaneous daytime PWV from Cimel AERONET (CA), GPS and RS92.
Comparison of daytime PWV from CA shows differences between GPS and
RS92 up to 0.18 cm. Two different filters, with and
approximate bandwidth of 10 nm and central wavelengths at
938 nm (Filter#1) and 937 nm (Filter#2), were
mounted onto the LC. Filter#1 is currently used in operational
AERONET sun photometers. PWV obtained with LC-Filter#1 showed an
overestimation above 0.18 and 0.25 cm compared to
GPS and RS92, respectively, and root-mean-square errors (RMSEs) up to 0.27 cm and 0.24 cm, respectively. Filter#2,
with a reduced out-of-band radiation, showed very low differences compared with the
same references (≤ 0.05 cm) and RMSE values ≤ 0.08 cm in the case of GPS precise orbits.
These results demonstrate the ability of the new lunar photometer to
obtain accurate and continuous PWV measurements at night, and the remarkable influence of the filter's transmissivity response
to PWV determination at nighttime. The use of enhanced bandpass filters
in lunar photometry, which is affected by more important inaccuracies
than sun photometry, is necessary to infer PWV with similar precision
to AERONET. |
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