CGRG Bibliography of Canadian Geomorphology
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Author : Brown, O.; and Hugenholtz, C.
Date : 2010.
Title : A new approach for mapping aerodynamic surface roughness.
Publication : Prairie Summit - Le sommet des Prairies. Joint Conference of Canadian Association of Geographers, Canadian Cartographic Association, Canadian Geomorphology Research Group, Canadian Remote Sensing Society / Conférence conjointe de l’Association canadienne des géographes, l’Association canadienne de cartographie, le Groupe canadien de recherche en géomorphologie, la Société canadienne de télédétection. June 1 to 5, 2010. Regina, Saskatchewan.
Issue : Program and Abstract Volume.
Page(s) : 87.
Abstract
Establishing suitable values of aerodynamic roughness is important for modeling a variety of biophysical processes (e.g., wind erosion, snow drifting, energy exchanges, habitat structure). Methods used to estimate roughness are dominated by field-based empirical techniques (wind profiling) and metrics derived from remote sensing imagery. These methods rely on major assumptions and require intensive data manipulation. Here we describe a new technique involving airborne LiDAR to estimate aerodynamic roughness over a large area and at a fine resolution. The study site is a vegetation-stabilized prairie dune field in southwestern Saskatchewan. The raw LiDAR point data were processed in a GIS using min/max filters in order to separate vegetation and underlying topography. The elevation difference between these two raster layers yielded a surface representing vegetation height. A roughness value was calculated with the empirical function developed by Meneti and Richie (1994): aerodynamic roughness = 0.33h^1.07, where h is vegetation height. This procedure yielded a unique roughness value for each raster cell, thus providing a high resolution representation of roughness variation. In contrast, existing methods generally provide one roughness value at a regional scale. Empirical testing of the LiDAR-derived aerodynamic roughness values is currently underway. Overall, this study demonstrates how the spatial representation of aerodynamic roughness can be enhanced through application of LiDAR data.
Bibliography of Canadian Geomorphology