Structural control on the topography of the Laji–Jishi and Riyue Shan belts in the NE margin of the Tibetan plateau: Facilitation of the headward propagation of the Yellow River system     

Erchie Wang  Xuhua Shi  Gang Wang  Chun Fan 《Journal of Asian Earth Sciences》2011,40(4):1002-1014

The Yellow River system, the largest river system in northern China, generally flows northeasterly through a series of linear mountain belts in the northeastern margin of the Tibetan plateau, the youngest of which are the Laji–Jishi Shan and Riyue Shan ranges, formed during late Cenozoic time due to NE–SW oblique shortening. As the product of the interaction between the tectonic process and the climate, the incision of the Yellow River system is a crucial parameter in models of the scale and timing of the crustal uplift and erosion in northeastern Tibetan plateau. Thus, whether the along-strike topographic feature of the Laji-Jishi Shan that is cut through by the Yellow River system and related streams is controlled by structural deformation or by erosion needs to be constrained. Our mapping shows that the variation in deformation along this mountain belt formed two structural saddles with relative low elevation in late Cenozoic time, through which the Yellow and Yaoshui Rivers cut into the plateau and drained a series of the Tertiary basins. The Yaoshui River is the tributary of the Huangshui River which itself flows into the Yellow River in the Lanzhou area. One saddle is present along the Yaoshui River valley, formed by NW–SE extension along the Riyue Shan Pass (RSP) normal fault, along which the Miocene and Mesozoic rocks were subsided against Proterozoic metamorphic rocks. These deformed rocks in the hanging wall are truncated by a sub-horizontal erosion surface at an elevation of 3200 m, on which terrace deposits are locally present, presumably middle Pleistocene in age. This terrace is incised by the Yaoshui River to an elevation of 3000 m, which yields 300 m of incision. Another saddle is along the Yellow River valley (the Xunhua-Linxia gouge) between the southern tip of the Laji Shan and the northern tip of the Jishi Shan, generated by en echelon folding. This structural saddle is underlain by the lower Cretaceous and Pliocene clastic rocks, which are truncated on the top by a rugged erosion surface at an average elevation of 3000 m. The Yellow River incised into this surface to an elevation of 1900 m, which yields 1100 m of incision. These two saddles, featured by topographic and structural low, were formed in the middle or late Miocene, and facilitated the headward propagation of the Yellow and Yaoshui Rivers, which initiated in early and middle Pleistocene time, respectively.  相似文献   

Spatial Distribution and Controlling Factors of Sedimentary Bodies in Jiaozhou Bay and Adjacent Sea Areas, Qingdao     

DONG Heping  LI Guangxue  LI shuanglin  LI Shaoquan  LI Chun 《青岛海洋大学学报(英文版)》2011,(2):106-112

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点云场景认知模式——泛化点云EI北大核心CSCD     

刘春  贾守军  吴杭彬  黄炜  郑宁  艾克然木·艾克拜尔 《测绘学报》2022,51(4):556-567

随着传感器技术和观测平台的迅速发展,点云大数据作为新型遥感的主要数据形式,已经逐渐成为场景感知的重要信息载体,并在地质灾害态势感知、自然资源定量调查和道路交通安全服务等国家重大战略需求中发挥了越来越显著的作用。与此同时,点云观测装备和国家重大战略需求的双重驱动促使空间场景从感知迈向了认知,也对认知处理的算法和算力提出了新的要求。为此,本文以点云场景认知的基本框架为线索,分析了多源点云耦合观测的研究现状,总结了点云场景认知处理的关键进展及其在国家重大战略需求中的典型应用,并凝练了点云场景认知当前面临的主要问题。在此基础上,本文聚焦点云场景认知的前沿挑战,避开传统欧氏空间而转到高维张量流形空间进行点云数据处理,提出了“泛化点云”的科学概念和技术框架,为突破点云场景认知处理的算法和算力提供研究思路。  相似文献   

Sequestration of arsenate from aqueous solution using 2-line ferrihydrite: equilibria,kinetics, and X-ray absorption spectroscopic analysis     

Woo Chun Lee  Soon-Oh Kim  James Ranville  Seong-Taek Yun  Sun Hee Choi 《Environmental Earth Sciences》2014,71(8):3307-3318

Arsenic(V), as the arsenate (AsO₄ ^3?) ion and its conjugate acids, has a strong affinity on Fe, Mn, and Al (oxyhydr)oxides and clay minerals. Removal of arsenate from aqueous solution by poorly crystalline ferrihydrite (hydrous ferric oxide) via a combination of macroscopic (equilibria and kinetics of sorption) and X-ray absorption spectroscopic studies was investigated. The removal of arsenate significantly decreased with increasing pH and sorption maxima of approximately 1.994 mmol/g (0.192 mol_As/mol_Fe) were achieved at pH 2.0. The Langmuir isotherm is most appropriate for arsenate sorption over the wide range of pH, indicating that arsenate sorption preferentially takes place at relatively homogenous and monolayer sites rather than heterogeneous and multilayer surfaces. The kinetic study demonstrated that arsenate sorption onto 2-line ferrihydrite is considerably fast, and sorption equilibrium was achieved within the reaction time of 2 h. X-ray absorption near-edge structure spectroscopy indicates no change in oxidation state of arsenate following interaction with the ferrihydrite surfaces. Extended X-ray absorption fine structure spectroscopy supports the efficient removal of arsenate by the 2-line ferrihydrite through the formation of highly stable inner-sphere surface complexes, such as bidentate binuclear corner-sharing (²C) and bidentate mononuclear edge-sharing (²E) complexes.  相似文献   

基于深度学习的遥感影像目标自动提取技术研究     

王诗洋  李淳  于兴超 《地理信息世界》2021,28(2):120-124

为研究重要目标信息的自动化快速提取,本文基于PyTorch、CUDA等环境并在GPU运行下,利用CycleGAN算法进行深度学习的模型训练.通过GeoServer对谷歌影像进行地图切片等处理,制作上海市浦东新区的船舶、机场、岸线的训练数据集.模型训练后其模型测试的结果实现了基于高分辨率遥感影像的目标信息自动化提取的科学目标.比较目标地物如船舶、机场、岸线等的信息提取效果,结果表明3种瓦片等级尤其17级瓦片下进行的多种目标信息自动化提取效果均较好,且在地物目标监测及军事应用方面具有重要意义.  相似文献   

基于图论法对城市水系连通性表征及优化     

傅春  邓俊鹏  欧阳欢蕤  付耀宗  张静 《地理科学》2022,42(11):2028-2038

基于景观生态学中“点–边”数量关系建立水系环度（α）、节点连接率（β）和网络连通度（γ）3种水系连通性评价指标,绘制出南昌市水系“节点–廊道”有向图,并以城市湖水体引流化污为切入点来优化城市水系连通性。研究表明：① 南昌市城区水系存在廊道空间分布不均匀,湖节点与其他水系节点连接的廊道较少等问题;② 优化后的城区水系相较于现在水系,其中水系环度（α）提高75%,节点连接率（β）提高14.88%,网络连接度（γ）提高14.63%。在城市水系连通性优化中,不应过分追求连通性而盲目增加湖泊廊道,应在连通性与湖泊连接的廊道数量之间保持一个平衡关系,以免水体污染物在湖泊中淤积。  相似文献   

Construction of a Comprehensive Observation Network for Natural-Resource Elements in Heihe River Basin,NW China     

PEI Xiaolong  HAN Xiaolong  YANG Hanwen  GAO Tiansheng  ZHANG Chun  GONG Lun  WANG Jiangyulong 《资源与生态学报(英文版)》2022,13(5):946-954

The construction of a comprehensive observation platform for natural-resource elements would provide data support for studies of dynamic changes in various natural resources, and could serve the needs of natural-resource management and the construction of ecological civilization during a period of global change. As the second-largest inland river basin in NW China, the Heihe River Basin (HRB) lies in the central part of the Silk Road Economic Belt, consequently, pilot studies of resource management in the basin are urgently needed. This paper describes the construction of a comprehensive natural-resource elements observation network in the HRB to meet requirements for natural-resource management, based on natural-resource and Earth-system science. Based on current observations and research, thirteen observation stations were established in different river basins through integration with existing stations, reconstruction and upgrading, and new construction. The main types of land-surface resources in the HRB (grassland, forests, rivers, lakes, deserts, wetlands, and farmland) were included in the observation network constructed for the monitoring of natural-resource elements. Long-term, continuous, and stable observation can yield key data concerning coupling processes, trends of change, and rates of change in natural resources. This is of great significance in improving cognitive ability, scientific management, and strategic decision-making regarding natural resources in the HRB, and can provide a reference paradigm for the observation of and research into natural resources in other basins.  相似文献   

准噶尔盆地西北缘达尔布特断裂的运动学特征   总被引：3，自引：0，他引：3       下载免费PDF全文

樊春  苏哲  周莉 《地质科学》2014,49(4):1045-1058

达尔布特断裂是准噶尔盆地西北缘的边界断裂,本文通过大量的野外地质调查并结合遥感解译,发现该断裂具有明显的左行走滑特征,其最大位错量出现在其西南段,达到60 km左右。根据野外的观察,达尔布特断裂是一条经历过多期变形的断裂,运动学特征指示了该断裂的各期活动均为左行走滑。它与准噶尔盆地东北缘北西-南东向的右行走滑断裂一起,构成了一组共轭断裂系,是印欧板块碰撞造成青藏高原强烈抬升并向北扩展的远程效应,同时也受到西伯利亚板块向南运动的影响。和什托洛盖盆地是在断裂走滑过  相似文献   

三峡库区短颌鲚(Coilia brachygnathus)新建种群的年龄结构、生长特征及遗传多样性分析     

陈辙聿  陶怡曦  叶勤  王果  王文波  范士琦  何春  李云 《海洋与湖沼》2022,53(2):430-439

2019~2020年在三峡库区巫山(WS)、万州(WZ)、丰都(FD)、涪陵(FL)4个采样点采集到新建短颌鲚(Coilia brachygnathus)种群153尾个体,基于鳞片和10个微卫星DNA标记进行年龄结构、生长特征与遗传多样性分析。结果显示,短颌鲚种群体长分布范围为102.1~301.6mm,平均体长(196.6±40.0)mm;体重分布范围为1.90~79.70g,平均体重(17.70±13.06)g。短颌鲚种群年龄组为1~5龄,其中2龄和3龄为优势年龄组,占总个体数的82.35%。体长-体重呈幂函数指数关系,属于正异速生长类型。微卫星DNA标记分析结果显示,10个微卫星位点共检测到82个等位基因,各群体平均等位基因数(N_a)为5.600 0~7.300 0,平均有效等位基因数(N_e)为3.541 4~3.831 5,平均观测杂合度(H_o)为0.617 7~0.700 0,平均期望杂合度(H_e)为0.682 3~0.702 9之间,平均多态信息含量(PIC)为0.628 5~0.648 4。4个群体的遗传多样性水平均较高,呈现出由三峡库区下游至上游逐渐减小的特点。遗传结构分析结果显示,群体间遗传分化水平很低,遗传变异主要来源于个体内部。结果表明,三峡库区短颌鲚种群处于快速扩张阶段,4个群体均具有较丰富的遗传多样性,遗传结构未发生显著群体分化,群体间基因交流频繁。由此提示,三峡库区短颌鲚很可能来源于三峡大坝下种群扩张迁入三峡库区水域而繁殖建群。  相似文献   

郑州“7·20”极端暴雨的水汽输送特征          下载免费PDF全文

于腾飞  李春  石剑 《海洋气象学报》2022,42(3):69-76

在亚洲中高纬度“两槽一脊”的稳定环流形势下,西北太平洋副热带高压和台风“烟花”“查帕卡”等共同作用,引导水汽在郑州地区辐合,导致2021年7月19—21日郑州地区出现降水极值超过800 mm的罕见极端暴雨(以下简称为“郑州“7·20”极端暴雨”),造成重大人员伤亡和财产损失。针对此次郑州“7·20”极端暴雨过程,采用HYSPLIT模式追踪其水汽来源和输送特征。结果表明:郑州“7·20”极端暴雨的水汽主要来自北太平洋西部和南海北部,北太平洋西部的水汽受西北太平洋副热带高压和台风“烟花”的共同影响,南海北部的水汽受台风“查帕卡”和“烟花”的共同影响。水汽主要在850 hPa以下高度输送,而来自南海北部的水汽在向北输送的过程中逐渐抬升,临近郑州地区时接近700 hPa。基于HYSPLIT后向追踪的水汽轨迹进行定量计算,得到来自北太平洋西部和南海北部的水汽贡献分别约占73%和27%。  相似文献