摘要
以SRTM3-DEM为数据源，在ArcGIS支持下，采用水文分析以及DEM分析数据与地质图、卫星图像和地形图区域数据综合对比分析，结合实地调查及前人研究成果，对莱州湾南岸的弥河、白浪河、潍河3条典型河流河网河间地的提取进行了研究，并对不同流域河间地比率的空间关系、流域地貌侵蚀对比与区域变化、全新世河型及河型转换以及区域地貌发展阶段进行了研究。通过DEM的水文分析、河网提取、河间地制图，得到了每条河流、每种累积流量取值下河网中的河问地，从而提出了快速提取河间地的一种新方法。区域空间上，河间地比率自西向东存在弱的增大变化。流域侵蚀综合分析表明：3条河流曾明显下切，即西部的弥河以单河道截切式下切；中部的自浪河以拓展式下切；东部的潍河呈嵌入式下切。表明西部侵蚀下切幅度大于东部（西部河流侵蚀速度快于东部），从而印证了河间地比率西小、东大的空间变化。对古河型（／河网）分析表明，全新世以来有网状河、扇状分汊河、汇聚型河、顺直河和曲流河5种河型。河型转换受控于气候变化、基准面下降和不均衡的构造抬升。将研究区全新世的河流地貌演化分为全新世早阶段、全新世中期早阶段、全新世中期晚阶段、全新世晚期早阶段和全新世晚期晚阶段5个阶段。
The south coast of the Laizhou Bay has typical fluvial landform, and three rivers of Mihe River, Bailanghe River and Weihe River in this region were selected in this study. Based on the data of SRTM 3-DEM, the 1/250000 geological map of Weifang City Sheet compiled by the Geological Survey Institute of Shangdong Province in 2005 and the 1/50000 topographic map published by National Administration of Surveying and Mapping of China in 1998 and landsat TM image, by means of ArcMap, and by the analyses of hydrology and history geomorphology and general analysis, this paper has studied the extract method of interfluves and the spatial change of the interfluves ratio and evolution relationship among the drainage and channel pattern of the Holocene and the evolution of geomorphology. Two stages are included in the interfluves extraction, the first is the extract of streamnet for DEM, and the second is interfluves mapping for the extracted streamnet. In streamnet extraction, this study has selected three thresholds （Mihe River, Bailanghe River and Weihe River） of flow accumulation （Flowacc） ≥ 500, ≥ 50 and ≥ 5 of each drainage, and 9 streamnets are in total obtained; in interfluves mapping, the interfluves range is limited between the endpoints of the first order stream and the drainage boundary. The interfluves ratio adopts the ratio of interfluves area of some drainage and its areas. The result shows that the ratio of streamnet above is situated in 0. 31-0.44. The ratio of the three kinds of threshold fits in line with a logarithmic curve and strict obedience cubic polynomial curve for each drainage. In the region, the interfluves ratio shows a weaken tendency of increasing from west to east. When the Flowacc ≥500, the ratio increases from O. 408 of the Mihe to 0. 416 of the Bailanghe and till 0. 433 of the Weihe, and obviously it is fully consistent with the trend above; when the Flowacc ≥50 and ≥ 5, the ratio increases from O. 357 of the Bailanghe to 0. 404 of the Weihe, and from 0. 312 of the Bailanghe to 0. 332 of the Weihe. The ratio among the both rivers also reflects the trend above, but excepting the Mihe. And at the same time, the trend above confirmed the evolution information of drainage. In the west part, Mibe channel cut the shallow-covered ancient channels in its both sides and forces the ancient channels lied on high location, and it forms a cut-cut pattern of single channel; in the middle part, the drainage boundary now among the Bailanghe and the Yuhe from DEM migrates towards the east being relative to the ancient boundary restored by Yihe Formation, it forms a cut pattern of expansion; and in the east part, Weihe drainage now from DEM lies the inner of its ancient channel zones, and it forms a cut pattern of embeded inner. This maybe illustrates that the erosion degree of the river in the west part is heavier than the erosion degree of the river in the east and is correspondent with the tendency of the interfluves ratio above. The evolution of fluvial geomorphology can summarize historic channel patterns and the transform among them. The channel patterns of Holocene have Anastomosing River, Fan-shaped Anabranched River, Converge River, Straight River and Meandering River. The following 4 situations are included in the transform of channel pattern： （1） The transform from Lake and Marshes to Anastomosing River, accrued before 8- 7 ka B. P.; （2） The transform from Anastomosing River to Anabranched River. Accrued in about 7ka B. P. , maybe controlled by warm climate after the period of the latest cold climate （24- 10ka B. P.） during the last glacial period, which led to the growth of Changwei Plain ; （3） The transform from Anabranched River to.Converge River. In this situation, once a little descending of base level accrued, then the base level was relatively steady, and as a sign there was the existence of a series of ancient lakes in the south coast of the Laizhou Bay; （4） The transform from Converge River to Straight River. The river quickly deepen accompanied with the rapid descending of base level, which led to the ancient laky disintegration from Eastern Han till Qing Dynasty; （5） The transform from Straight River to Meandering River. The base level descended slowly down, but then the Meandering River was cut again.
出处
《第四纪研究》
CAS
CSCD
北大核心
2015年第2期475-483,共9页
Quaternary Sciences
基金
山东省自然科学基金项目（批准号：ZR2013DL006）资助
关键词
DEM
河间地提取
河型及河型转换
地貌演化
莱州湾南岸
DEM, extract of interfluves, channel pattern and its transform, evolution of geomorphology,the south Laizhou Bay
作者简介
杜国云男53岁教授海岸带过程与第四纪环境研究E-mall：duguoyun2003@163．com
