基岩河道流域地貌研究的定量计算方法及其进展

Quantitative Analysis and Significance of Bedrock Channel Fluvial Landscape Response Time Scale

造山带基岩河道流域地区的地貌演化定量化的分析主要关注气候、构造等外在因素以及河流内在调节机制对地貌演化的影响。总结了关于基岩河道流域地貌分析的定量方法和模型的研究进展。定量计算方法主要利用detachment-limited模型并结合具体的区域状况对气候变化或构造产生的扰动响应状态进行定量化分析,其中地貌起伏分析涉及对地貌在气候变化下的地貌起伏增强或降低的响应趋势分析,地貌响应时间域涉及地貌在气候变化、构造扰动或两者共同作用下的地貌响应时间问题。研究表明,气候作用引发的剥蚀加强并不能导致地貌起伏增大。气候变化、构造扰动或两者共同作用的地貌响应行为主要是气候、构造以及原地条件的函数。不同的区域其地貌响应时间域不同。在中国西高东低的地貌格局所决定的水文体系中,基岩河道流域占有重要地位。地貌定量化特别是地貌响应时间域的研究,有助于理解造山带的地貌演化过程,以及辨析构造运动、气候变化和地表过程特定的时空尺度。

The quantitative research of geomorphologic revolution in bedrock channel fluvial landscape plays a significant role in the discussion of the relationship among tectonics, climate and surface process. While the quantitative analysis concentrates on external factors such as tectonics, climate and on the influence added by the internal tuning mechanism of the rivers. This article summarizes the research progresses of the quantitative methods and models with a focus on the geornorphologic analysis in bedrock channel drainage. The detachment-limited model is used as the main calculation method, combined with specific regional conditions to analyse quantitatively the response to the variation of climate and tectonic perturbation. The relief analysis concentrates on the trend of the increase and decrease of the relief in response to climate change the analysis of landscape response time scale resolves the problem of landscape response time influenced by climate variation or tectonic perturbation, or both. Current researches prove that the increase of denudation induced by climate change cannot increase surface relief. Influenced by climate variation or tectonic perturbation, or both, the landscape response behaviors are mainly the function of climate, tectonics and local conditions, with the landscape response time scale changing i＇n different zones. The bedrock channel drainage is also very important in the fluvial system decided by the Chinese landscape framework, which is mainly characterized by a higher attitude in west and a lower in east. The quantitative research on the landscape, especially the landscape response time scale can not only be very helpful for further understandings of the landscape revolution process in orogens, but also is very significant for distinguishing specific time-space scale of tectonics, climate changes and surface processes.