HR: 16:30h
AN: G12A-03 INVITED     [PDF]
TI: Measuring Landscape Scale and Testing Landscape Evolution Models With an Airborne Laser Swath Map of the Gabilan Mesa, California
AU: * Perron, J T
EM: perron@eps.berkeley.edu
AF: Department of Earth and Planetary Science, University of California at Berkeley, 307 McCone Hall, Berkeley, CA 94720 United States
AU: Kirchner, J W
AF: Department of Earth and Planetary Science, University of California at Berkeley, 307 McCone Hall, Berkeley, CA 94720 United States
AU: Dietrich, W E
AF: Department of Earth and Planetary Science, University of California at Berkeley, 307 McCone Hall, Berkeley, CA 94720 United States
AB: High-resolution topographic data acquired through airborne laser swath mapping (ALSM) allows geomorphologists to observe and measure features that cannot be resolved in coarser topographic maps. One of the most promising applications of ALSM data in geomorphology is the measurement of landscape properties that can be used to calibrate and test landscape evolution models. We illustrate this process with examples from the analysis of an ALSM dataset covering 40 km$^{2}$ of the Gabilan Mesa, a soil-mantled landscape in central California's Salinas Valley. The fine-scale ridge-and-valley topography of the Gabilan Mesa is characterized by a regular spacing of ~180m between adjacent ridgelines. This regular spacing, which is not apparent in coarser digital elevation models (DEMs), defines a dominant topographic ``wavelength.'' The magnitude of this wavelength is hypothesized to reflect spatial and tectonic boundary conditions and the relative rates of hillslope and channel erosion. We apply signal processing techniques to the ALSM data to measure the magnitude and regularity of the topographic wavelength. We then extract topographic profiles and drainage areas from the ALSM data that, when combined with exposure ages obtained from cosmogenic radionuclides, allow us to calibrate hillslope and channel erosion laws. The output of a numerical model based on these erosion laws can be analyzed by the same signal processing techniques applied to the ALSM-derived DEM. In this way the DEM and the model can be compared statistically. We also consider several challenges posed by the acquisition, processing and analysis of ALSM datasets that are relevant to terrain analysis, including the potential distortion of small-scale topographic features by filtering algorithms and the computational load imposed by large data volumes and grid-based representations of topography.
DE: 1294 Instruments and techniques
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 1640 Remote sensing
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Geodesy [G]
MN: 2003 Fall Meeting