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| Titel |
Aerodynamic roughness length estimation from very high-resolution imaging LIDAR observations over the Heihe basin in China |
| VerfasserIn |
J. Colin, R. Faivre |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 14, no. 12 ; Nr. 14, no. 12 (2010-12-22), S.2661-2669 |
| Datensatznummer |
250012538
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| Publikation (Nr.) |
 copernicus.org/hess-14-2661-2010.pdf |
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| Zusammenfassung |
| Roughness length of land surfaces is an essential variable for the
parameterisation of momentum and heat exchanges. The growing interest in the
estimation of the surface turbulent flux parameterisation from passive
remote sensing leads to an increasing development of models, and the common
use of simple semi-empirical formulations to estimate surface roughness.
Over complex surface land cover, these approaches would benefit from the
combined use of passive remote sensing and land surface structure
measurements from Light Detection And Ranging (LIDAR) techniques. Following
early studies based on LIDAR profile data, this paper explores the use of
imaging LIDAR measurements for the estimation of the aerodynamic roughness
length over a heterogeneous landscape of the Heihe river basin, a typical
inland river basin in the northwest of China. The point cloud obtained from
multiple flight passes over an irrigated farmland area were used to separate
the land surface topography and the vegetation canopy into a Digital
Elevation Model (DEM) and a Digital Surface Model (DSM) respectively. These
two models were then incorporated in two approaches: (i) a strictly
geometrical approach based on the calculation of the plan surface density
and the frontal surface density to derive a geometrical surface roughness;
(ii) a more aerodynamic approach where both the DEM and DSM are introduced in
a Computational Fluid Dynamics model (CFD). The inversion of the resulting
3-D wind field leads to a fine representation of the aerodynamic surface
roughness. Examples of the use of these three approaches are presented for
various wind directions together with a cross-comparison of results on
heterogeneous land cover and complex roughness element structures. |
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