On the future navigability of Arctic sea routes: High-resolution projections of the Arctic Ocean and sea ice     

《Marine Policy》2017

The rapid Arctic summer sea ice reduction in the last decade has lead to debates in the maritime industries on the possibility of an increase in cargo transportation in the region. Average sailing times on the North Sea Route along the Siberian Coast have fallen from 20 days in the 1990s to 11 days in 2012–2013, attributed to easing sea ice conditions along the Siberian coast. However, the economic risk of exploiting the Arctic shipping routes is substantial. Here a detailed high-resolution projection of ocean and sea ice to the end of the 21st century forced with the RCP8.5 IPCC emission scenario is used to examine navigability of the Arctic sea routes. In summer, opening of large areas of the Arctic Ocean previously covered by pack ice to the wind and surface waves leads to Arctic pack ice cover evolving into the Marginal Ice Zone. The emerging state of the Arctic Ocean features more fragmented thinner sea ice, stronger winds, ocean currents and waves. By the mid 21st century, summer season sailing times along the route via the North Pole are estimated to be 13–17 days, which could make this route as fast as the North Sea Route.  相似文献   

矿井明渠流量测定方法     

罗奕  向新  王勇 《煤田地质与勘探》2006,34(1):56-58

讨论了各种矿井水流量测定方法在矿井中实际测量时遇到的技术难题,提出了合理使用矿井流量测量装置获取正确测量结果的技术方法。实际应用证明,正确的测量方法可以达到2%3%的测量精度。   相似文献   

Effects of the planned ephesus recreational canal on freshwater–seawater interface in the Selçuk sub-basin, İzmir-Turkey     

M. Zeki. Camur  Hasan Yazicigil 《Environmental Geology》2005,48(2):229-237

An artificial water canal opening is planned between the Agean Sea and the historical Ephesus site for the sake of tourism in the Selçuk sub-basin. In order to predict the effects of the planned canal on freshwater–seawater interface and related contamination in the aquifer, 3-D numerical density dependent flow and solute transport simulations were carried out. The simulations included the pre-pumping and pumping periods without a canal and the prediction period in the presence of the canal. Chloride concentration comparisons of the results obtained from the pre-pumping period and the pumping period indicate that the freshwater-seawater interface in the aquifer has progressed inland due to artificial discharge in the sub-basin. Drawdown during the pumping period is about 15 cm. The planned canal opening could further lower the groundwater levels in the area and would change the groundwater flow directions in the first 4 years. Then the levels and flow directions will nearly recover. However, the canal opening could cause further seawater intrusion into the aquifer to the extent that groundwater would be unfit to use for irrigation after the seventh year of the canal opening in the irrigation cooperative II wells area and would be unfit to use for drinking purposes after the tenth year in the municipality wells area located at the south of the cooperative II wells. On the other hand, the cooperative I wells would not be effected by the opening of the canal.  相似文献   

基于游客行为的旅游线路组织研究   总被引：11，自引：0，他引：11  

马晓龙 《地理与地理信息科学》2005,21(2):98-101

为寻求合理的旅游线路组织方式，指导区域旅游线路体系建设和旅行社线路组织，该文对国内外旅游线路的组织模式进行总结和评价，认为现有线路组织模式未能与我国国情衔接，缺乏实用性和对游客行为特征的考虑。提出基于游客行为特征的旅游线路组织模式，并分析影响这种旅游线路组织的要素及相互作用关系。以西安旅游区为例，通过对资源分布特征和旅游线路组织现状的分析，以该模型为基础，优化和构建了西安旅游区旅游线路组织的宏观发展框架。  相似文献   

Moessbauer and XRD characterization of contaminated sediments by coal mining drainage in Neath Canal, South Wales, UK     

Guodong ZHENG Akihito Kuno Talib Abdulameer Mahdi David J. Evans Masaaki Miyahara Yoshio Takahashi Motoyuki Matsuo Hiroshi Shimizu 《中国地球化学学报》2006,25(B08):137-138

Sediment cores were collected from the upstream of the Neath Canal in South Wales and characterized for their mineral compositions and iron speciation in order to understand the influence of sedimentary properties on the contaminants of heavy metals. The sediments in the canal have been polluted by ocherous precipitate with heavy metals such as arsenic since a major mine water discharge in spring 1993. The sediment core was obtained just from the discharge point in the canal and distinguished into three layers in the field regarding to their physical properties including visible color, sediment particle composition and dryness. X-ray diffraction （XRD） and M6ssbauer spectroscopy revealed vertical variations of minerals and iron species in depth of the sediment profile. The upper layer, reddish-brown, is wet muddy precipitant and is very fine in particle size, consisting mainly of iron oxide and hydroxide. Arsenic is rich in this layer; probably the sorption on iron oxide surface is the main mechanism. The middle layer, 22.0-27.0 cm, is soft deposit in a yellow color and contains sheet silicate, calcite and goethite. The lower part below 27.0 cm is gray to dark gray in color and contains quartz, pyrite, coal particles that are much more similar to normal aquatic sediment. The upper two layers in brown and yellow colors as newly precipitated mud from AMD contain high concentrations of As, Ni under oxic conditions. The lower part as the old canal sediments under reducing conditions contains high Cu and Zn. Chromium is enriched in the limited part of the low layer, just beneath the boundary between the middle and low parts of the sedimentary column, where the redox conditions shifted from oxic to anoxic. It is clear that the distribution of these heavy metals is closely associated with the redox condition reflected in the iron speciation. Thus different treatments are necessary for each layer of the sediment since different mineral and geochemical properties of the sediment will give different impacts on the heavy metals.  相似文献   

矿井涌水量动态预测非稳定释水-断面流法     

傅耀军 《中国煤炭地质》2021,(1)

我国北方煤田上覆地下水系统含水层以砂岩为主,是矿井主要充水水源。除浅部、露头区外,上覆砂岩地下水系统总体上构成非径流型蓄水构造,弹性贮存是其地下水主要赋存状态,压力传导、局部渗流为地下水动力学模式,矿井涌水主要为承压含水层弹性释放。非充填开采,煤层上覆地层周期性冒裂形成冒裂二元结构体,其自身释水(弹性、重力)与其外侧含水层断面弹性释水叠加形成矿井涌水。冒裂二元结构体释水随冒裂周期发生,时间短暂。外侧含水层断面释水可用非稳定流定降深沟(渠)流方程描述,进而获得外侧含水层断面释水单宽流量。外侧含水层释水断面随冒裂周期性延展累积,迭代更新,矿井涌水流量随之变化。在研究、刻画外侧含水层释水断面延展、迭代时空规律基础上,给出含水层断面释水流量预测方法、公式,与冒裂二元结构体自身周期性释水流量叠加,获新的矿井涌水量预测方法—非稳定释水-断面流法。  相似文献   

Evolutionary process and development implications of traditional trade routes in the Himalayan region     

Wu  Shihai  Yan  Jianzhong  Zhang  Yili  Peng  Ting  Su  Kangchuan 《地理学报(英文版)》2022,32(9):1847-1865

Journal of Geographical Sciences - Traditional trade routes that penetrate the natural barrier of the Himalayas are critical for connecting major Chinese and South Asian markets. Research on these...  相似文献   

中国船舶首航东北航道及其展望   总被引：1，自引：0，他引：1       下载免费PDF全文

王洛  赵越  刘建民  韩淑琴 《极地研究》2014,26(2):276-284

北极航道按其处于地球上的地理方位可分为东北航道和西北航道,东北航道按航线所处的纬度范围则可分为北极低纬航线(北极近岸航线)、北极中纬航线(作为国际常规航线)、北极高纬航线、挺极航线。"雪龙"号于2012年夏季书写了中国船舶首航东北航道的航海史。"雪龙"号从东北航道的起点白令海峡开始,沿东北航道抵达冰岛,并沿北极高纬航线返回白令海峡,完成往返穿越北冰洋之旅。据此,本文对北极航道的分类提出了一些看法,对东北航道的商业航行情况进行了总结,在此基础上概述了"雪龙"号此次首航东北航道的整个进程和关键问题,同时对中国建立北极航道战略进行了思考并提出了建议。  相似文献   

中国地质学会印发精品地学研学路线、课程评选办法（试行）通知          下载免费PDF全文

孙莉莉 《地质论评》2022,68(4):68041479-68041480

为进一步规范地学类研学路线、课程建设与管理，顺利开展地学研学路线、课程的推荐与评选，中国地质学会秘书局修订了《中国地质学会精品地学研学路线、课程评选办法（试行）》，并经中国地质学会第40届理事会第三十七次常务理事会议（通讯）审批通过,现予以印发，请遵照执行。  相似文献