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| Titel |
Contrail study with ground-based cameras |
| VerfasserIn |
U. Schumann, R. Hempel, H. Flentje, M. Garhammer, K. Graf, S. Kox, H. Lösslein, B. Mayer |
| 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. 12 ; Nr. 6, no. 12 (2013-12-20), S.3597-3612 |
| Datensatznummer |
250085139
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| Publikation (Nr.) |
 copernicus.org/amt-6-3597-2013.pdf |
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| Zusammenfassung |
| Photogrammetric methods and analysis results for contrails observed with wide-angle cameras are
described. Four cameras of two different types (view angle < 90° or whole-sky imager)
at the ground at various positions are used to track contrails and to derive their altitude,
width, and horizontal speed. Camera models for both types are described to derive the observation
angles for given image coordinates and their inverse. The models are calibrated with sightings of
the Sun, the Moon and a few bright stars. The methods are applied and tested in a case
study. Four persistent contrails crossing each other, together with a short-lived one, are observed
with the cameras. Vertical and horizontal positions of the contrails are determined from the
camera images to an accuracy of better than 230 m and horizontal speed to 0.2 m s−1.
With this information, the aircraft causing the contrails are identified by comparison to traffic
waypoint data. The observations are compared with synthetic camera pictures of contrails
simulated with the contrail prediction model CoCiP, a Lagrangian model using air traffic movement
data and numerical weather prediction (NWP) data as input. The results provide tests for the NWP
and contrail models. The cameras show spreading and thickening contrails, suggesting
ice-supersaturation in the ambient air. The ice-supersaturated layer is found thicker and more
humid in this case than predicted by the NWP model used. The simulated and observed contrail
positions agree up to differences caused by uncertain wind data. The contrail widths, which
depend on wake vortex spreading, ambient shear and turbulence, were partly wider than simulated. |
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