Morphology of Alluvial Fan Longitudinal Profiles in the Parlung Tsangpo Basin

Published: 25 November 2025| Version 1 | DOI: 10.17632/2ws6xbb7kd.1
Contributors:
Pan Han,

Description

The longitudinal profile (LP) of an alluvial fan is a fundamental morphological feature that records formation processes and distinguishes fan types. Here, we quantitatively analyze LP morphology using data from 18 alluvial fans in the Parlung Tsangpo Basin (PTB) in southeast Tibet—an alpine valley basin hosting fluvial, colluvial, and debris-flow fans (FF, CF, and DF) shaped by distinct dominant processes. The data include the geomorphological characteristics of alluvial fans (location, area, length, mean slope, etc.), longitudinal profile concavity, local slope variability parameters, and corresponding channel longitudinal profile characteristics.This work aims to clarify morphological differences in the LPs of distinct alluvial fan types and provide data support for fan type identification.

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Topographic data from high-resolution RTK surveys, UAV photogrammetry, and Google Earth Pro allowed for the extraction and analysis of both fan surface and channel longitudinal profiles (LPs). The concavity of these LPs was quantified using two complementary methods: area ratio and regression analysis. Moreover, we employed the first derivative of slope relative to downfan distance from the fan apex and residual analysis from trend fitting to quantify downstream fluctuations and the "non-ideality" of local slopes in the LPs of different fan types.

Institutions

  • Key Laboratory of Water Cycle & Related Land Surface Processes Chinese Academy of Sciences
  • University of the Chinese Academy of Sciences

Categories

Geography, Morphometry

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