Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： Barchan and parabolic dunes can be transformed into each other and coexist in the same area, resultingin a unique landscape in which typical barchan dunes coexist with embryonic barchan and parabolic dunes. It ishelpful to understand the causes of their formation and execute targeted desertification prevention and controlprojects after studying their spatial distribution, morphological characteristics, and migration. Based on the Esrihistorical image service (World Imagery Wayback), the morphological parameters of the dunes in the coexistencezone of the barchan and parabolic dunes, west of Hunshandake Sandy Land, were extracted in three periods:January 15, 2008, June 4, 2011, and September 20, 2016, and the direction and velocity of the dune migrationwere calculated. The results indicate that typical barchan dunes are concentrated in 15 areas related to the drylake bed in the western part of the sandy land, whereas embryonic barchan and parabolic dunes are sequentiallydistributed around the periphery of the dry lake bed. The appearance of the dry lake bed was a key factor in thedevelopment of the typical barchan dunes in the Hunshandake Sandy Land. Therefore, more attention should bepaid to the desertification caused by the lake drying up. The analysis of morphological parameters of sand dunesin the fifth zone, where the co- existence of barchan and parabolic dunes is typically found, indicates that thetypical barchan and embryonic barchan dunes significantly differ from embryonic parabolic dunes. Thecorrelation analysis between the morphological parameters of sand dunes indicates that toss slope length, leeslope length, and bottom area are inherited from the barchan to parabolic dunes, with horns experiencing thegreatest changes during this process. Furthermore, the migration directions of the three types of dunes are almostequal but have varying migration velocities, as well as the factors that affect the migration of sand dunes. Themost significant impact on the embryonic parabolic dunes, whose vegetation cover is relatively high, was thevegetation cover, whose variation was consistent with that of NDVI during the same period. The most significantimpact on the typical barchan and embryonic barchan dunes, whose vegetation cover is relatively low, was windspeed, whose variation was consistent with that of DP and RDP during the same period. Additionally, otherfactors, including terrain, sand sources, and human activities, can influence the morphology and migration ofbarchan-parabolic dunes.
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-11 Cooperative journals: 《干旱区地理》
Abstract：水中可溶性离子的含量及各离子的比例关系是衡量水质的重要指标，但常用的方法不能同时反映这两种关系。Maucha图既可以反映8种主要阴、阳离子的总浓度，同时也可以指示各离子的相对浓度，兼顾了离子的绝对含量和相对含量，具有较强的实用性。但由于缺乏绘制Maucha图的专业软件，导致Maucha图在实际应用中受到很大限制。通过介绍Maucha图的演化过程，绘制Maucha图时建立坐标系及确定Maucha图各组成部分坐标值的方法，并阐述了基于Matlab语言实现Maucha图计算机输出的编程流程。最后以内蒙古浑善达克沙地东部地区为例，说明了Maucha图在天然水体水化学分析中的应用。该应用表明，Maucha图在反映样品矿化度、指示各离子的相对浓度和绝对浓度、判断水体水化学类型及水化学数据空间分析等方面均具有较强的优势，能显著提高水化学数据的可视化表达能力，丰富水化学图在水文地质中的应用，并为水化学数据更深层次的分析提供参考依据。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-10 Cooperative journals: 《干旱区研究》
Abstract：浑善达克沙地东部地区位于内蒙古高原，其天然水体为淡水。利用原始型Durov三线图对其天然水体进行水化学分类，结果表明，地表水水化学类型属于碳酸氢盐组，而地下水属于碳酸氢盐组、混合组和硫酸盐组多种类型。天然水体样品在Gibbs图中的分布表明，岩性控制是形成该地区天然水体水化学组成的主要因素，这种情况不同于我国西部和中部沙漠由于蒸发强烈而受控于蒸发-结晶作用的天然水体。天然水体的离子比例关系表明，地下水中蒸发盐岩和硅酸盐岩的风化程度较高，而碳酸盐岩风化程度低，这可能是由于地下水的水-岩作用时间长、二氧化碳供给不充分引起的；相反，由于水-岩作用时间短、二氧化碳供给充分，地表水中蒸发盐岩和硅酸盐岩的风化程度较低，而碳酸盐岩风化程度高。
Subjects: Geosciences >> Hydrology submitted time 2018-10-23 Cooperative journals: 《干旱区地理》
Abstract： 水化学分类是实现水资源可持续开发利用的重要前提之一。Durov三线图作为主要的水化学分类图因绘制复杂而限制了其在现实中的应用，且一些常见的水化学软件也不具备绘制Durov三线图的功能。Durov三线图包括原始型Durov三线图及在其基础上演变而成的扩展型Durov三线图。本文详细介绍了两种Durov三线图的差异、组成特征和投影原理，提出了在Durov三线图中建立坐标系的方法，并推导了将水化学数据投影到Durov三线图的公式。在此基础上，本文阐述了基于Matlab语言编程实现原始型Durov三线图和扩展型Durov三线图的方法和流程，并以公开发表的数据绘制了两种Durov三线图。基于相同的数据比较发现，相关水化学软件绘制的原始型Durov三线图及一些公开发表的研究成果中的扩展型Durov三线图与本文所用Matlab语言绘制的Durov三线图相一致，表明该程序准确可行。本程序既可以实现原始型Durov三线图的绘制，也可以实现常见水化学软件不能完成的扩展型Durov三线图的绘制。该程序的应用，将有助于Durov三线图的高效应用，特别是扩展型Durov三线图的应用不但可以作为水化学分类的依据，同时还可以指示某些水化学过程。
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