基于分形理论的1915—2000年渭河泾河口—潼关段河道演变研究
- 陕西师范大学 西北历史环境与经济社会发展研究院 西安 710062
- 收稿日期:
1900-01-01
- 修回日期:
1900-01-01
- 刊出日期:
2011-10-10
摘要: 渭河泾河口—潼关段是渭河平面形态中最活跃的部分。运用近百年来的多种地形资料，在调校民国地图测绘误差的基础上重建了1915—2000年本段渭河平面形态的空间矢量数据，使用盒维数法测算了其近百年来的分维D，发现D区间为\[1.0432, 1.0774\]。1915—1958年是本段河型在相对天然环境下的发展过程，D呈现动态平衡态势，虽有较大波动但整体较为稳定，渭河具有自身调节河型的能力；1969—2000年D急剧上升，虽然1960s—1970s泾河口—潼关段大量弯道消失，但渭河下游平面形态不断趋于复杂，其主要原因是三门峡水库引起的溯源淤积和下游筑堤限制了河型发展，河流自身调节河型的能力基本丧失。研究显示分形方法在描述半湿润区平原河流变化过程中，能更好反映河型发展趋势，也更加适合对多源地形资料中河流形态信息的处理。
- Center for Historical Environment & SocioEconomic Development in Northwest China of Shaanxi Normal University,Xi`an 710062
- Received Date:
1900-01-01
- Rev Recd Date:
1900-01-01
- Publish Date:
2011-10-10
Abstract: Jing River estuaryTongguan is the most unstable section of Wei River.The bend developed sharply and disappeared rapidly,and river course changed frequently as well.The processing of the morphological changing was reconstructed based on both kinds of terrain materials during 19152000A.D. and the modulation in the error of surveying and mapping on roc map.The trend was described by fractal dimension (D), the rang of index D changing is \[1.0432, 1.0774\]. Relatively,under the natural environment, the shape of Wei River(Jing River estuaryTongguan) is a dynamic equilibrium during the 43 years(19151958), the D displayed balance.Wei River is the biggest tributaries.
It has the ability to adjust the shape itself. The D went up high sharply during 19692000A.D.Although many corners of Jing River estuaryTongguan have disappeared, the shape of Weihe downstream has became complicated consistently. However, in the last 50a, unreasonable human activity, such as Sanmenxia project, building dam and flood plain reclamation, leading to the retrogressive deposition and restricting the moveable space of Wei River, growing of D rapidly in this period. The changing of D displayed the low reach of Wei River lost the function of adjusting morphology since 1960s.According to the historical records, there was a morphological changing during 1860s, the low reach trend to more curved, maybe during the 1860s1960s the rang of D is larger than the decades after 1960s.With the method of Fractal Geometry (Benoit Mandelbrod put forward in 1975,the morphology between the mix form and the regulate form),this research precisely shows the development of river style in the process of describing changing in the river on the plaint,it also suitable for the processing of the message which contains river morphology in terrain with a abundance of source.
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