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- Title
The topographic signature of a major typhoon.
- Authors
Tseng, Chih‐Ming; Lin, Ching‐Weei; Dalla Fontana, Giancarlo; Tarolli, Paolo
- Abstract
In August 2009, the typhoon Morakot, characterized by a cumulative rainfall up to 2884 mm in about three days, triggered thousands of landslides in Taiwan. The availability of LiDAR surveys before (2005) and after (2010) this event offers a unique opportunity to investigate the topographic signatures of a major typhoon. The analysis considers the comparison of slope-area relationships derived by LiDAR digital terrain models (DTMs). This approach has been successfully used to distinguish hillslope from channelized processes, as a basis to develop landscape evolution models and theories, and understand the linkages between landscape morphology and tectonics, climate, and geology. We considered six catchments affected by a different degree of erosion: three affected by shallow and deep-seated landslides, and three not affected by erosion. For each of these catchments, 2 m DTMs were derived from LiDAR data. The scaling regimes of local slope versus drainage area suggested that for the catchments affected by landslides: (i) the hillslope-to-valley transitions morphology, for a given value of drainage area, is shifted towards higher value of slopes, thus indicating a likely migration of the channelized processes and erosion toward the catchment boundary (the catchment head becomes steeper because of erosion); (ii) the topographic gradient along valley profiles tends to decrease progressively (the valley profile becomes gentler because of sediment deposition after the typhoon). The catchments without any landslides present a statistically indistinguishable slope-area scaling regime. These results are interesting since for the first time, using multi-temporal high-resolution topography derived by LiDAR, we demonstrated that a single climate event is able to cause significant major geomorphic changes on the landscape, detectable using slope-area scaling analysis. This provides new insights about landscape evolution under major climate forcing. Copyright © 2015 John Wiley & Sons, Ltd.
- Subjects
OPTICAL radar; DIGITAL elevation models; TYPHOONS; CONVENTIONAL signs in topography; LANDSLIDES
- Publication
Earth Surface Processes & Landforms, 2015, Vol 40, Issue 8, p1129
- ISSN
0197-9337
- Publication type
Article
- DOI
10.1002/esp.3708