塔克拉玛干沙漠腹地高大复杂纵向沙垄区沙丘分形特征

Fractal features of dunes over the high longitudiral complex ridges in the hinterland of the Taklimakan Desert

为了探讨塔克拉玛干沙漠小尺度风沙地貌形态特征，对沙漠腹地复杂纵向沙垄横断面的上覆沙丘的分形特征进行了研究。沙丘形态野外测量采用RTK（real—time kinematic）技术，并通过南方测绘软件（South Survey）量算形态特征参数。研究结果表明：（1）沙丘形态具有分形特征，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；（2）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，表明复杂纵向沙垄上覆沙丘形态有自相似性；（3）沙丘的各形态特征参数变异系数的空间变化趋势一致，且与分形维数呈显著的线性正相关（P〈0．05），表明沙丘形态分形维数能客观反映沙丘形态特征。在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。

In order to explore the morphological features of the small-scale aeolian sand landform, this paper studies fractal features of dunes over the cross-section of complex ridges in the hinterland of Taklimakan Desert. The paper precisely measures morphologic features through RTK （real-time kinematic）technology in field, and mappings the main parameters by South Survey. The result shows ： （ 1 ） dunes patterns are of fractal feature, fractal dimension of pancdke dunes and sand sheets is 1. 292 2 ,fractal dimension of crescent dunes is 1. 286 6,fractal dimension of simple linear dunes is 1. 102 5, fraetal dimension of crescent dune chains is 1. 085 ; （2） 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 dune chains are the main dunes patterns over the hige loagitadinal complex ridges and dunes in the areas arc of self-similarity; （3） 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.