浑善达克沙地固定沙丘风蚀坑形态变化及其动力学机制  

Morphological changes and dynamic mechanism of blowouts on fixed dunes in the Otingdag sandy land,China

作　　者：周炎广 王卓然 青达木尼 胡日娜 殷婕 武子丰 哈斯额尔敦 Yanguang Zhou;Zhuoran Wang;Damuni Qing;Rina Hu;Jie Yin;Zifeng Wu;Eerdun Hasi(School of Natural Resources,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)

机构地区：[1]北京师范大学地理科学学部自然资源学院,北京100875

出　　处：《科学通报》2023年第11期1298-1311,共14页Chinese Science Bulletin

基　　金：国家重点研发计划(2016YFC0500805);国家自然科学基金(42271005)资助。

摘　　要：风蚀坑是固定沙丘活化的重要标志,也是半干旱沙质草原地区沙漠化的首要环节.因此,准确理解风蚀坑形态变化及其动力学过程对区域荒漠化的治理具有重要意义.浑善达克沙地东南缘固定沙丘不同部位上发育了多种形态的风蚀坑,对其形态和气流结构的野外观测结果表明,2010~2021年,各类型风蚀坑长度、宽度和面积均持续增加,整体形态有向椭圆形或槽形发展的趋势;风蚀坑坑体的扩张方向与坑内蚀积格局具有高度一致性;气流在固定沙丘迎风坡坡脚几乎未发生偏转,而在沙丘中部和丘顶发生明显偏转,且偏转角度与区域风向相关;风蚀坑形态和区域气流方向共同决定了风蚀坑内部的气流分布模式.此外,本研究认为,固定沙丘地形对区域气流的再改造作用可能是导致风蚀坑形态差异的根本原因;风蚀坑形态决定了坑内气流分布模式,而气流方向和风速变化影响着坑内蚀积格局,最终改变了风蚀坑形态演变方向.Blowouts are a major indicator of fixed dune reactivation,and their continuous occurrence and expansion aggravate the process of regional desertification.Therefore,research on the morphological evolution and dynamic processes of blowouts is paramount not only to understanding reactivation processes in stabilized and semistabilized dune fields but also to accurately assessing regional desertification trends.At present,much research has focused on blowouts in coastal dunes and flat grasslands,and little research has focused on the evolution mode of blowouts that have developed on fixed dunes in semiarid inland areas.Moreover,the morphological changes and airflow dynamics of blowouts are usually analyzed separately,and research integrating the two is still insufficient.In this paper,a fixed dune on the southern edge of the Otingdag sandy land was selected as the research object.A high precision real-time kinematic global positioning system(RTK-GPS)and 172D ultrasonic anemometers were used to measure the topography and airflow of four blowouts with different morphologies on the fixed dunes,and the multiperiod imaging data and multiyear meteorological data were used to monitor the morphological changes of each type of blowout and the regional meteorological conditions.The goal of this research is to reveal the morphological evolution,erosion-accumulation characteristics and airflow distribution patterns of each type of blowout and to discuss the relationship among the topography of fixed dunes,morphology of various blowouts and airflow variation.The results showed that the length,width and area of each type of blowout continued to increase from 2010 to 2021,and the overall shapes of each type of blowout tend to be oval or trough-shaped.The expansion direction of the blowout shape has a general corresponding relationship with the erosion-accumulation pattern in the deflation basin.The eastern and southeastern edges of the deflation basins are the most severely eroded,and their overall shapes expand from west to east.Re

关 键 词：形态变化 气流 风蚀坑 固定沙丘 

分 类 号：P931.3[天文地球—自然地理学] X171.4[环境科学与工程—环境科学]