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| Titel |
A method for parameterising roughness and topographic sub-grid scale effects in hydraulic modelling from LiDAR data |
| VerfasserIn |
A. Casas, S. N. Lane, D. Yu, G. Benito |
| 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. 8 ; Nr. 14, no. 8 (2010-08-17), S.1567-1579 |
| Datensatznummer |
250012401
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| Publikation (Nr.) |
 copernicus.org/hess-14-1567-2010.pdf |
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| Zusammenfassung |
| High resolution airborne laser data provide new ways to explore the role of
topographic complexity in hydraulic modelling parameterisation, taking into
account the scale-dependency between roughness and topography. In this
paper, a complex topography from LiDAR is processed using a spatially and
temporally distributed method at a fine resolution. The surface topographic
parameterisation considers the sub-grid LiDAR data points above and below a
reference DEM, hereafter named as topographic content. A method for
roughness parameterisation is developed based on the topographic content
included in the topographic DEM. Five subscale parameterisation schemes are
generated (topographic contents at 0, ±5, ±10, ±25 and ±50 cm) and roughness values are calculated using an equation based on the
mixing layer theory (Katul et al., 2002), resulting in a co-varied
relationship between roughness height and topographic content. Variations in
simulated flow across spatial subscales show that the sub grid-scale
behaviour of the 2-D model is not well-reflected in the topographic content
of the DEM and that subscale parameterisation must be modelled through a
spatially distributed roughness parameterisation. Variations in flow
predictions are related to variations in the roughness parameter. Flow
depth-derived results do not change systematically with variation in
roughness height or topographic content but they respond to their
interaction. Finally, subscale parameterisation modifies primarily the
spatial structure (level of organisation) of simulated 2-D flow linearly with
the additional complexity of subscale parameterisation. |
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