黄土丘陵区不同尺度侵蚀沟发育过程与沟蚀预报模型

As its threat and destroy to land resources and ecological security, gully erosion has been the primary issue and difficult scientific question in the field of soil erosion research. It becomes possible to monitoring the gully erosion processes at larger scale than before as the rapid development of monitoring techniques such as remote sensing, Radar and photogrammetry. Because of the unique landform of loess gully system, the Loess Plateau is the focus of research and prevention of gully erosion. Previous studies were limited at small time and spatial scale; especially for gully system, long-term developing dynamics, processes and mechanism, more quantitative research is needed. Taking the semi-arid loess hilly area as study area, with the new techniques to collecting information of gully system, such as high resolution of Stereoscopic Satellite Images, 3D laser scanning and positioning photographic monitoring, combined with relief map of 1: 10,000 surveyed and mapped in 1980, one of the objectives of the project is to explore different monitoring methods for gully variation at scale of decades, inter-annual and inner-annual. Employing a variety of modern data mining and statistical techniques, the project will analyze characteristics of channel system formed on the hilly and gully loess area including permanent gully, deep incised gully and stabilized gully, reveal three-dimensional development process and mechanism at scale of decades, inter-annual and inner-annual, determine the effecting factors of channel morphological features and development rates, and establish models for forecasting gully formation and development at mesoscale, estimating of gully erosion at small watershed scale and modelling gully head retreat processes. Results of this project will provide a method of gully monitoring, predicting, and preventing and will enhance scientific theories on gully erosion.

沟蚀是最具威胁和破坏性的土壤水蚀类型，切沟是最活跃的侵蚀沟，沟蚀过程因为监测难度大，一直是科学难题，但近期高分立体遥感技术的发展为较大尺度监测沟蚀三维过程提供了可能性。黄土高原因其独特的地貌系统和严重的水土流失，成为沟蚀防治重点区域。以往研究的时空尺度小，尤其是沟蚀长期发育过程和机制的量化研究非常有限，缺少有效的沟蚀预报方法，严重影响土壤侵蚀普查和水土保持效益评价的准确性。本项目以陕西吴起县为研究区，利用高分遥感立体像对、三维激光定位测量以及长期定位连续摄影摄像监测等新技术手段采集侵蚀沟信息，结合1980年大比例尺地形图，分析黄土丘陵区切沟和冲沟等沟谷形态特征；揭示不同类型侵蚀沟长期、年际和季节的三维发育过程；建立中尺度切沟形成和发育的经验模型和小流域沟蚀预报模型，探索沟头发育过程模型。预期能够丰富和发展土壤侵蚀理论，为不同尺度的沟蚀监测和预报提供方法，为沟蚀治理提供依据。

黄土高原地貌系统独特，水土流失严重，切沟是最活跃的侵蚀类型。沟蚀过程因为监测难度大，一直是科学难题，但近期高分立体遥感技术的发展为较大尺度监测沟蚀三维过程提供了可能性。2017-2020年，在国家自然科学基金面上项目的资助下，以陕北吴起、子洲、绥德和山西吉县为研究区，采用卫星影像解译、三维激光测量、无人机遥感等监测方法，研究了黄土丘陵区切沟和冲沟等沟谷形态特征，不同类型侵蚀沟的发育特征；确定了切沟形成阈值条件，建立了切沟形成和发育的经验模型。项目积累了大量沟蚀测量及其影响因子监测的基础数据，取得了暴雨条件下典型丘陵区的切沟形成和发育等关键数据，并取得了以下研究成果：（1）初步探索出一套基于高分卫星遥感和无人机遥感的切沟侵蚀快速监测方法,以及基于三维激光扫描定位监测沟头三维发育过程的方法；提出了基于9项指标的切沟沟头活跃性评价方法；明确了黄土高原丘陵沟壑区第一副区和第二副区不同类型侵蚀沟形态参数和分布特征的差异以及两区切沟三维发育特征的差异；揭示了黄土丘陵沟壑区切沟形成的地貌阈值和降水阈值，建立了场暴雨尺度的切沟侵蚀预报模型和小流域中等时间尺度切沟侵蚀预报模型。项目完成了预期目标，发表学术论文8篇，其中，发表SCI/EI收录5篇，已接受待刊SCI期刊论文1篇。依托本项目，指导硕士毕业生5名，本科毕业生4名。研究成果丰富和发展了沟蚀理论，参加国际会议学术交流6人次，受到国际同行的关注和好评，为黄土高原沟蚀预报和治理提供了方法和实用工具，具有实践意义和推广应用价值。