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Xinjiang Normal University (2008)

A Study on the Morphologic Characteristics and Causes of Parabolic Dunes in Takeermohuer Desert in Yili by Dem

曾雅娟;Zeng Ya Juan

Titre : A Study on the Morphologic Characteristics and Causes of Parabolic Dunes in Takeermohuer Desert in Yili by Dem

Auteur : 曾雅娟;Zeng Ya Juan

Grade : Master’s Theses 2008

Université : Xinjiang Normal University

Résumé
The safety and sustainability of human’s habitat have been threatened so seriously by increasing global desertification that the desertification has become one of the most serious ecological problems which attract much attention in the world. Morphological characteristics and causes of dunes relate to the mobility of the desert. Consequently, studying on aeolian landform especially on dune morphology is significant to sand prevention and controlling. Moreover, parabolic dune is one of representative dune morphology. This paper takes Takeermohuer desert as the investigative object, because it’s a fixed and semi-fixed desert influenced by the typical western wind with arid climate and human activities,the main morphological of the aeolian landform is parabolic dunes.I In the past century, natural vegetations trongly interferred by human activities, in the middle and the northern region of the desert landscape the parabolic dunes obviously had morphological variation, and the secondary topography morphological is complex and varied, locally evolve into similar fixed dunes or cross crescent dune chain, the liquidity of the entire desert enhances and has the trend of expansion.Based on sandstorms geomorphology、remote sensing、geographical information systems、and surveying, this paper used wild 3S survey work platform and RTK technology to access three-dimensional data of sample areas, used ArcGIS 9.1 to generate DEM, extracted basic topographical factors of the sand dunes, typical sections from DEM, calculated the characteristics value of the vector, analyzed and expressed morphological characteristics of parabolic dunes of Takeermohuer desert.Using RS、GIS and DEM quantitatively analyzed the relationship between parabolic dune and vegetation. At the same time, through analyzing historical data, weather data, the paper explored the cause of parabolic dune of Takeermohuer desert. Finally obtained some conclusions as follow:1. During the process of select sample areas 3S field survey work platform realized real-time comparison of remote sensing images, field landscape and dynamic analysis and selection of sample areas. By RTK technology analysised the 3D Data that 96% of the elevation error of less than 0.02m , the result showed that the RTK technology is feasible in the quantitative research of the morphologic characteristics of dunes.2. The discussion of the extraction method of dune morphology factors by DEM and study of feasibility of the dynamic dune morphology, widen the G1S technology applications field.The sand ridge line automatically extracted from elevation deviate degree filter.3. Quantitative studies of the relationship between parabolic dune and vegetation draw the vegetation on Takeermohuer desert’s parabolic dune mainly distributes in the deflation basic and trailing ridge, the least in windward slope, there are two reasons for this distribution, one is water contents in sand layers of the tops were lower than those of the slopes ; both of them were lower than those of the interdunes. Another is that the wind erosion has a different affect of the same dune distributing in different location. Vegetation grow is hampered in windward slope for the strong wind erosion. Although vegetation coverage exceed to 50 percent on the Takeermohuer desert’s parabolic dune ,the nature vegetation is destroyed continuely ,the evolution of dune morphology from parabolic dune to longitudinal dune4. Parabolic dune formation is common results of natural and man-made factors in Takeermohuer desert. The natural factors not only includes vegetation types, distribution, coverage, but also includes sand material sources, wind power agency, precipitation, water sand and river agency and so on ; Man-made factors are also play an important role in the process of the parabolic dune formation and development, it speed up the evolution of the parabolic dune

Mots clés : Dune morphology; Parabolic dunes; Takeermohuer desert; DEM; RTK technology;

Présentation (CNKI)

Page publiée le 15 septembre 2014, mise à jour le 23 novembre 2017