风蚀地貌形态与过程研究进展

Advances in the Study of Geomorphology and Process of Wind Erosion Landforms

辨析了雅丹、风蚀坑等主要风蚀地貌的概念,雅丹是典型的风蚀正地貌形态,通过回顾雅丹地貌形态与过程的研究历史与进展,发现目前对其发育过程的认识尚不清楚,并且只关注了对残存土墩的观测和分析,没有充分重视凹槽的形态动力学过程;风蚀坑是典型的风蚀负地貌形态,特别是草原景观转变为沙地景观的临界阈现象,目前已经对独立风蚀坑的形态、气流特征、沉积物粒度以及植被演替过程等方面进行了初步研究,但由于风蚀坑形态是多因素共同作用的结果,需要由单因素观测转向综合分析其形态动力学过程。认为对风蚀过程机理及其模拟的研究中,在利用风洞模拟实验、野外观测等手段对风蚀过程微观尺度进行研究的同时,也需要加强通过遥感和GIS手段从景观尺度对风蚀地貌发展变化过程进行分析。

With global warming and drought enhancement,the geomorphic process of wind erosion landforms becomes one of the main surficial processes in arid and semi-arid areas.However,compared with wind accumulated landforms,less attention has been given to the wind erosion landforms.This paper reviews the processes of initiation,evolution,dynamics and geomorphology of yardangs and blowouts.Yardang and blowout are two main wind erosion landforms,one is positive and one is negative.The generation of yardangs results from complex interactions between internal factors and external factors,and they are also influenced by weathering process,fluvial erosion and mass movement.Aerodynamic system produces differential pressures giving rise to vorticity which is one of the most frequent and important wind movements responsible for the erosion.Blowout geomorphology,dynamics and evolution are also examined.Blowouts are the threshold of grasslands converting to shrublands in arid and semi-arid ecosystems.Throughout the review,the gaps in present understanding of dune processes and a range of ideas for new research possibilities are provided.