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| Titel |
Correction technique for Raman water vapor lidar signal-dependent bias and suitability for water vapor trend monitoring in the upper troposphere |
| VerfasserIn |
D. N. Whiteman, M. Cadirola, D. Venable, M. Calhoun, L. Miloshevich, K. Vermeesch, L. Twigg, A. Dirisu, D. Hurst, E. Hall, A. Jordan, H. Vömel |
| 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. 11 ; Nr. 5, no. 11 (2012-11-28), S.2893-2916 |
| Datensatznummer |
250003182
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| Publikation (Nr.) |
 copernicus.org/amt-5-2893-2012.pdf |
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| Zusammenfassung |
| The MOHAVE-2009 campaign brought together diverse instrumentation for
measuring atmospheric water vapor. We report on the participation of the
ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and
Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also
report on the performance of the corrected Vaisala RS92 radiosonde
measurements during the campaign, on a new radiosonde based calibration
algorithm that reduces the influence of atmospheric variability on the derived
calibration constant, and on other results of the ALVICE deployment. The
MOHAVE-2009 campaign permitted the Raman lidar systems participating to
discover and address measurement biases in the upper troposphere and lower
stratosphere. The ALVICE lidar system was found to possess a wet bias which
was attributed to fluorescence of insect material that was deposited on the
telescope early in the mission. Other sources of wet biases are discussed and
data from other Raman lidar systems are investigated, revealing that wet biases
in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear
to be quite common in Raman lidar systems. Lower stratospheric climatology of
water vapor is investigated both as a means to check for the existence of
these wet biases in Raman lidar data and as a source of correction for the
bias. A correction technique is derived and applied to the ALVICE lidar water
vapor profiles. Good agreement is found between corrected ALVICE lidar
measurments and those of RS92, frost point hygrometer and total column water.
The correction is offered as a general method to both quality control Raman
water vapor lidar data and to correct those data that have signal-dependent
bias. The influence of the correction is shown to be small at regions in the
upper troposphere where recent work indicates detection of trends in
atmospheric water vapor may be most robust. The correction shown here holds
promise for permitting useful upper tropospheric water vapor profiles to be
consistently measured by Raman lidar within NDACC (Network for the Detection
of Atmospheric Composition Change) and elsewhere, despite the
prevalence of instrumental and atmospheric effects that can contaminate the
very low signal to noise measurements in the UT. |
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