| 题名 | 塔克拉玛干沙漠腹地高大复合纵向沙垄区沙丘形态特征及其空间变异研究 |
| 作者 | 范冬冬 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院．新疆生态与地理研究所 |
| 授予地点 | 北京 |
| 导师 | 雷加强，中国科学院新疆生态与地理研究所 |
| 关键词 | 塔克拉玛干沙漠 |
| 其他题名 | The spatial variation of morphologic parameters of dunes on the high complex longitudinal ridges in the hinterland of the Taklimakan Desert |
| 学位专业 | 自然地理学 |
| 中文摘要 | 沙丘形态是与当地起沙风信情况、地面物质组成（沙源丰富程度）、地面的起伏和水分植被情况相适应的，因此下垫面条件是风沙运动转化的重要条件，是沙丘形态变化重要的影响因素。为了探讨中尺度地貌形态对上覆次级沙丘形态特征及其空间变异的影响，本文采用RTK（实时动态差分）测量技术，对塔克拉玛干沙漠腹地高大复合纵向沙垄横断面的次级沙丘进行了野外测量，在计算机中通过南方测绘软件（South Survey）量算形态特征参数，并运用经典统计分析和分形方法对沙丘的形态特征及其空间变异进行了研究，同时结合研究区气象站的多年风资料以及野外实地观测的风速和输沙率数据，对研究区的风动力背景进行了研究，分析了沙丘形态空间变异的风动力和输沙强度等方面的原因。主要结论如下：（1）塔克拉玛干沙漠腹地复合纵向沙垄区，起沙风主要集中在3~8月，其中以5月份为全年起沙风高频月，3~8月的起沙风约占全年的89.07%。从起沙风的方向分布来看，N、NNE、NE、ENE和E五个方向为主，其起沙风次数占总起沙风次数的75.57%，其中以NNE风最强，其次为N、ENE和E风，NE风最弱。全年输沙势为33.26 VU，合成输沙势为21.37 VU，合成输沙方向为43.5°，方向变率指数大、中、小比率都存在。（2）沙丘形态具有分形特征，分形维数空间变化体现出一定的规律性。饼状沙堆和沙片的分维数是1.2922，新月形沙丘的分维数是1.2866，简单线性沙丘的分维数是1.1025，新月形沙丘链的分维数是1.085。在不同地貌部位之间，分维数差异不大（1.0～1.3），变异系数为0.06，反映复杂纵向沙垄上覆沙丘形态有自相似性。沙丘形态各特征参数的变异系数空间变化趋势一致，且与分形维数呈显著正线性相关（p<0.05），表明沙丘形态分形维数能客观地反映沙丘形态特征。塔克拉玛干沙漠腹地纵向沙垄区，沙丘形态分形维数可以作为反映风沙环境特征的定量指标。 （3）简单横向沙丘形态特征参数及其相互关系具有空间变异性。在8个地貌部位之间，沙丘形态特征参数（不包括迎风坡度）存在显著性差异，主要体现为：在垄顶、沙垄背风坡、其他地貌部位（包括垄间地和沙垄迎风坡）三者之间的差异。沙丘在垄间地→沙垄迎风坡→垄顶→沙垄背风坡的移动过程中，高度、长度、宽度急剧变小，翼展度先增大后减小，发育指数则先减小后增大。地貌部位、输沙风强度以及沙丘活动强度是驱动沙丘形态空间变异的因素。沙丘高度与翼展度余弦有负对数关系，发育指数与高度、迎风坡度成负线性相关，这些相关性的显著程度在垄顶、背风坡较高，在垄间和迎风坡较低。（4）纵向沙垄表面风速、输沙强度具有一定的空间变化。从垄间地到沙垄迎风坡再到垄顶，风速、输沙率逐渐增大，在垄顶达到最大值；从垄顶到背风坡，风速、输沙率开始下降。地貌下垫面起伏程度导致了风速和输沙强度的空间分异，进而造成沙丘形态的空间变异。因此沙垄各地貌部位的地貌形态本身是通过改变风动力和输沙强度来影响沙丘形态的。Dunes morphology matches with sand moving wind, abundance of sand, surface undulation, condition of water and vegetation. So, surface conditions are essential terms of sand movement. It is also the important element which influences dunes morphology variation. In order to explore the impact that middle-scale landform causes on sub-dunes morphology and spatial variation of it, the paper precisely measures morphologic features of on the cross-section of tall complex ridges in the hinterland of the Taklimakan Desert，through RTK technology in field, and mapping the main parameters by South Survey. In addition, by utilizing statistical methods and fractal theory, we undergo the research into the dunes morphologic features and spatial variation of it. Taking a look at wind dates recorded in weather station in many years and sediment transport rate observed in field, we do the research into the background of wind power in the study area, and analyze the causes of dunes morphology in spatial variation, for example wind power, sediment transport strength. The main conclusions are as follows: （1） On the cross-section of high complex ridges in the hinterland of the Taklimakan Desert，sand-moving wind happens mainly between March and August，which happens most frequently in May. It covers about 89.07% of the whole year from March to August. From its direction，we can know that N、NNE、NE、ENE and E are main directions，whose frequencies are 75.57% of the total. NNE is the strongest，N，ENE and E is the next，and NE is the weakest. Drift Potential yearly is 33.26 VU，while resultant drift potential is 21.37 VU. Resultant drift direction is 43.5°. The value of RDP/DP includes maximum，medium，minimum. （2） Dunes patterns are of fractal feature. fractal dimension of elliptic or Irregular bottom dunes is 1.2922，fractal dimension of crescent dunes is 1.2866，fractal dimension of simple linear dunes is 1.1025，fractal dimension of crescent dunes chains is 1.085. Among different landscape sites，variation of fractal dimension is small（1.0～1.3）with variation coefficient being 0.06，which reflects that crescent dunes and crescent dunes chain are the main dunes patterns on the tall longitudinal complex ridges and dunes in the areas are of self-similarity. Variation coefficients of all morphological parameters are of the same spatial variations trends and there are significant positive linear relations between the coefficient and fractal dimension（p<0.05）. This shows that fractal dimension could be used to describe morphological feature. In the hinterland of Taklimakan Desert，fractal dimension of dunes could be used as an integrated quantitative index to evaluate the aeolian sand environment. （3） The morphologic parameters of the simple transverse dunes and their relations are in spatial variation. The parameters（not including windward slope） is different significantly among eight landscape sites，especially，showing differences among the ridge top、the ridge leeward and other sites（including the inter-ridge corridor and the ridge windward）. Moving in the inter-ridge corridor →the ridge windward →the ridge top →the ridge leeward, length, width and height suddenly get small. The cosine of the angle between the two horns is big then small, while developing index is small then big. Landscape sites、wind strength（transporting sand） and dunes movement strength are the factors driving the spatial variation of the morphologic parameters of the simple transverse dunes. There is negative LN relation between height and the cosine of the angle between the two horns; and there are negative linear relations between developing index and height or windward slop. However，the significant extents of these correlations are high in the ridge top or the ridge leeward，while low in the inter-ridge corridor or the ridge windward. （4）On longitudinal ridges, wind speed and sediment transport strength are in spatial variation. From the inter-ridge corridor to the ridge top and by way of the ridge windward, wind speed and sediment transport strength become gradually large. The two values are the largest on the ridge top, while they become gradually small from the ridge windward to the ridge leeward. Surface undulation causes wind speed and sediment transport strength in spatial variation, thus causing dunes patterns in spatial variation. So, geomorphologic patterns on different landscape sites of ridges have an effect on dunes patterns by changing wind speed and sediment transport strength. |
| 学科主题 | 荒漠化防治 |
| 公开日期 | 2010-11-12 |
| 页码 | 共55页 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.xjlas.org/handle/365004/8400]  |
| 专题 | 新疆生态与地理研究所_中国科学院新疆生态与地理研究所(2010年以前数据) |
| 推荐引用方式 GB/T 7714 | 范冬冬. 塔克拉玛干沙漠腹地高大复合纵向沙垄区沙丘形态特征及其空间变异研究[D]. 北京. 中国科学院．新疆生态与地理研究所. 2009. |
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