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| Titel |
Synchronous polar winter starphotometry and lidar measurements at a High Arctic station |
| VerfasserIn |
K. Baibakov, N. T. O'Neill, L. Ivanescu, T. J. Duck, C. Perro, A. Herber, K.-H. Schulz, O. Schrems |
| 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 ; 8, no. 9 ; Nr. 8, no. 9 (2015-09-18), S.3789-3809 |
| Datensatznummer |
250116579
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| Publikation (Nr.) |
 copernicus.org/amt-8-3789-2015.pdf |
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| Zusammenfassung |
| We present recent progress on nighttime retrievals of aerosol and cloud
optical properties over the PEARL (Polar Environmental Atmospheric Research
Laboratory) station at Eureka (Nunavut, Canada) in the High Arctic
(80° N, 86° W). In the spring of 2011 and 2012, a
star photometer was employed to acquire aerosol optical depth (AOD) data, while
vertical aerosol and cloud backscatter profiles were measured using the
CANDAC Raman Lidar (CRL). We used a simple backscatter coefficient threshold
(βthr) to distinguish aerosols from clouds and, assuming that
aerosols were largely fine mode (FM)/sub-micron, to distinguish FM aerosols
from coarse mode (CM)/super-micron cloud or crystal particles. Using
prescribed lidar ratios, we computed FM and CM AODs that were compared with
analogous AODs estimated from spectral star photometry. We found
(βthr dependent) coherences between the lidar and
star photometer for both FM events and CM cloud and crystal events with
averaged, FM absolute differences being <∼0.03 when associated
R2 values were between 0.2 and 0.8. A βthr sensitivity
study demonstrated that zero crossing absolute differences and R2 peaks
were in comparable regions of the βthr range (or physical
reasons were given for their disparity). The utility of spectral vs.
temporal cloud screening of star photometer AODs was also illustrated. In
general our results are critical to building confidence in the physical
fidelity of derived, weak amplitude, star photometry AODs and, in turn,
towards the development of AOD climatologies and validation databases for
polar winter models and satellite sensors. |
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