Analysis of longitudinal profiles along the eastern margin of the Qinghai-Tibetan Plateau

Abstract

Abstract:Resulting from the collision of the Eurasian and Indian plates, the Qinghai-Tibetan Plateau is commonly known as the 'roof of the world'. Collectively the Yarlung Tsangpo, Nu, Lancang, Yangtze, Yalong, and Yellow River basins drain the eastern margin of the plateau. In this paper, we utilize Shuttle Radar Topography Mission elevation data to examine morphometric and relief attributes of these basins to reveal insights into tectonic activity and rates of incision. A robust technique using Matlab is proposed to alleviate errors associated with SRTM data in the derivation of river longitudinal profiles. Convex longitudinal profiles are interpreted to be a product of uplift rates that exceed rates of channel incision along the entire margin of the QinghaiTibetan Plateau. Highest relief towards the south reflects extensive fluvial incision. High relief is also prominent along major active faults. Erosion patterns are related to distance from knickpoints. Highest rates of erosion and incision are evident towards the south, with decreasing values towards the north, suggesting a link between tectonic activity and erosion.

Bumps in river profiles: uncertainty assessment and smoothing using quantile regression techniques

“…Common approaches for removing errors in river profiles include running average filters (Hayakawa and Oguchi, 2006), contour interval subsampling (Wobus et al, 2006), smoothing splines (Harbor et al, 2005), and locally weighted regression (Aiken and Brierley, 2013). However, all of these approaches face similar problems: they fail to remove spikes if the length of the moving window is too small and average out potentially important features if the window is too large (Aiken and Brierley, 2013).…”

“…However, all of these approaches face similar problems: they fail to remove spikes if the length of the moving window is too small and average out potentially important features if the window is too large (Aiken and Brierley, 2013). Furthermore, conventional smoothing algorithms are typically applied to individual river reaches rather than entire river networks, which may lead to sharp discontinuities at river confluences.…”

“…Furthermore, conventional smoothing algorithms are typically applied to individual river reaches rather than entire river networks, which may lead to sharp discontinuities at river confluences. Finally, even robust approaches that aim at reducing the influence of individual outliers on the smoothed curve (Aiken and Brierley, 2013) may yield profiles that contain sections with downstream increasing elevation that results from long sections where valley bottom elevations are overestimated. An example of how outliers may generate downstream increasing elevations in profiles smoothed by a running average is shown in Fig.…”

How concave are river channels?

“…Wobus et al (2006a) made recommendations for preprocessing of slope-area data that are still used in many 15 studies: first, the DEM is smoothed, then topographic gradient is measured over either a fixed reach length or a fixed drop in elevation (Wobus et al (2006a) recommends the latter), and then the data are averaged in logarithmically spaced bins. More recently, authors have proposed alternative channel smoothing strategies (e.g., Aiken and Brierley, 2013;Schwanghart and Scherler, 2017): all these proposed methods use some form of smoothing and averaging.…”

Geomorphology and environmental management of the Yellow River source zone

“…Aiken and Brierley (2013) show how tectonic factors have fashioned geomorphic variability of river systems across the eastern margin of the QTP. Hillslope instability in the region has been markedly impacted by alterations to vegetation cover and infrastructure development (see Figure 1d).…”