A two-layer model for studying 2D dissolved pollutant runoff over impermeable surfaces     

Taotao Zhang  Yang Xiao  Dongfang Liang  Hongwu Tang  Junzeng Xu  Saiyu Yuan  Nairu Wang  Bin Luan 《水文研究》2021,35(5):e14152

Dissolved pollutants in stormwater are a main contributor to water pollution in urban environments. However, many existing transport models are semi-empirical and only consider one-dimensional flows, which limit their predictive capacity. Combining the shallow water and the advection–diffusion equations, a two-dimensional physically based model is developed for dissolved pollutant transport by adopting the concept of a ‘control layer’. A series of laboratory experiments has been conducted to validate the proposed model, taking into account the effects of buildings and intermittent rainfalls. The predictions are found to be in good agreement with experimental observations, which supports the assumption that the depth of the control layer is constant. Based on the validated model, a parametric study is conducted, focusing on the characteristics of the pollutant distribution and transport rate over the depth. The hyetograph, including the intensity, duration and intermittency, of rainfall event has a significant influence on the pollutant transport rates. The depth of the control layer, rainfall intensity, surface roughness and area length are dominant factors that affect the dissolved pollutant transport. Finally, several perspectives of the new pollutant transport model are discussed. This study contributes to an in-depth understanding of the dissolved pollutant transport processes on impermeable surfaces and urban stormwater management.  相似文献   

Numerical Simulation of Magnetic Reconnection Driven by the Laser Helmholtz Capacitor-coil Targets     

XU Shan-shan  MEI Zhi-xing  ZHONG Jia-yong  LIN Jun 《Chinese Astronomy and Astrophysics》2021,45(2):131-146

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Investigation of inner-basin variation: Impact of large reservoirs on water regimes of downstream water bodies     

Xue Dai  Zhongbo Yu  Guishan Yang  Chong-Yu Xu  Rongrong Wan 《水文研究》2021,35(5):e14241

Large dams and reservoirs alter not only the natural flow regimes of streams and rivers but also their flooding cycles and flood magnitudes. Although the effect of dams and reservoirs has been reported for some vulnerable locations, the understanding of the inner-basin variation with respect to the effects remains limited. In this study, we analyse the Three Gorges Dam (TGD) built on the Changjiang mainstream (Yangtze River) to investigate the dam effect variations in the system of interconnected water bodies located downstream. We investigated the effect of flow alterations along the downstream river network using discharge time series at different gauging stations. The river–lake interactions (referring to the interactions between the Changjiang mainstream and its tributary lakes i.e. the Dongting and Poyang lakes) and their roles in modifying the TGD effect intensity were also investigated in the large-scale river–lake system. The results show that the water storage of the tributary lakes decreased after the activation of the TGD. Severe droughts occurred in the lakes, weakening their ability to recharge the Changjiang mainstream. As a consequence, the effect of the TGD on the Changjiang flow increase during the dry season diminished quickly downstream of the dam, whereas its impact on the flow decrease during the wet season gradually exacerbated along the mainstream, especially at sites located downstream of the lake outlets. Therefore, when assessing dam-induced hydrological changes, special attention should be paid to the changes in the storage of tributary lakes and the associated effects in the mainstream. This is of high importance for managing the water resource trade-offs between different water bodies in dam-affected riverine systems.  相似文献   

末次冰消期（1.9万年）以来冲绳海槽中部黏土矿物来源及其环境响应          下载免费PDF全文

田旭  胡邦琦  王飞飞  黄威  丁雪  宋维宇  徐方建 《中国地质》2020,47(5):1501-1511

基于采自冲绳海槽中部的CS2站柱状沉积物黏土矿物和AMS¹⁴C年代分析，探讨了末次冰消期以来冲绳海槽中部黏土矿物的物质来源及其环境指示意义。结果显示，CS2站黏土矿物以伊利石为主，其次为绿泥石，高岭石和蒙脱石含量较少。根据黏土矿物分布趋势变化，CS2站柱状沉积物可划分为3个阶段：阶段（I 19~12 ka BP）和阶段Ⅱ （12~8 ka BP）期间沉积物主要来源于长江，台湾和黄河物质也有一定影响，其物质来源主要受海平面升降的控制；阶段Ⅲ（8~0 ka BP）主要来源于长江和台湾，黄河贡献有限，主要受黑潮演化的影响。CS2站（蒙脱石+高岭石） （/伊利石+绿泥石）比值可以作为东亚季风演化的矿物学指标，指标变化显示出东亚冬季风强度相对夏季风的强度在16.4~14.8 ka BP和12.8~11.6 ka BP期间有两次显著的加强，指示当时气候相对寒冷干燥，结果可以与格陵兰冰心δ¹⁸O和三宝洞δ¹⁸O记录等很好对比。  相似文献   

Near-surface soil stabilization by enzyme-induced carbonate precipitation for fugitive dust suppression     

Song  Jun Young  Sim  Youngjong  Jang  Jaewon  Hong  Won-Taek  Yun  Tae Sup 《Acta Geotechnica》2020,15(7):1967-1980

Acta Geotechnica - To resolve the environmental and sustainability issues from fugitive dust emission and conventional mitigation methods, multiple experiments were conducted to evaluate the...  相似文献   

基于主成分分析法和监测数据的阿尔泰山采金废弃矿区人工恢复措施效益分析          下载免费PDF全文

艾沙江·艾力  徐海量  苑塏烨 《干旱区地理》2019,42(2):288-294

本文以阿尔泰山两河源保护区采金废弃矿区为研究区，从地形、土壤、水分和地表植被4个方面出发，结合矿区现有条件，设置11种恢复措施，选取丰富度指数、优势度指数、多样性指数、均匀度指数、生物量、植被盖度、物种数及土石比等7个评价指标，采用主成分分析法，得出不同恢复措施的主成分得分及生态效益排名。结果表明，单一恢复措施，如推平、羊群驻扎、泥浆等基本上是从某一个方面来考虑生态恢复的，存在一定的缺陷，恢复效益排名比较靠后；多种措施相结合，不仅能改善土壤环境，也会引起植物群落多样性格局的变化，生态恢复效益很好；同一种恢复措施，施行年限越长恢复效果越好。  相似文献   

湘黔桂新元古代拉伸纪晚期地层年代格架对比及关键地质事件初探     

张嘉玮  陈建书  吴滔  叶太平  陈明华  代雅然  邓小杰  牟军 《地学前缘》2020,27(4):1-16

湘黔桂地区发育一套完整的新元古代拉伸纪晚期地层(下江群及其相当地层),是研究扬子克拉通与华夏板块碰撞拼接后华南大陆裂谷盆地演化的重要载体。本文报道了贵州省铜仁市万山区清水江组上部、平略组底部及中部变质凝灰岩和沉凝灰岩的年龄,分别为(763.8±5.5) Ma(N=24,MSWD=0.29)、(760.2±4.1) Ma(N=25,MSWD=0.39)、(759.1±3.9) Ma(N=26,MSWD=0.38)。通过对湘黔桂地区下江群及其相当地层中已有火山岩、火山碎屑沉积岩、含凝灰质岩石年龄的系统梳理与分析研究,进一步确定下江群其及相当地层的沉积时限在822~715 Ma,桂北丹洲群三门街组玄武岩是在武陵造山后伸展背景下湘黔桂地区裂谷最大裂陷时期的产物,清水江组与平略组内大量的火山物质可能来源于江南造山带东段800~760 Ma的中酸性喷出岩。结合地层、岩性、年代特征,本文恢复了湘黔桂盆地新元古代拉伸纪晚期的演化历史,并认为该套地层符合建立下江系条件。  相似文献   

准噶尔盆地玛湖凹陷西斜坡三叠系百口泉组扇三角洲优质储集层预测          下载免费PDF全文

桑林翔  刘军  王贵文  王苏天  李全  张云龙 《古地理学报》2020,22(6):1053-1064

针对准噶尔盆地玛湖凹陷西斜坡风南地区三叠系百口泉组扇三角洲砂岩物性空间变化大、优质储集层(孔隙度大于7.4%,渗透率大于0.05×10^-3μm²)预测难的问题,在沉积岩石学、地震沉积学以及地震反演和解释理论指导下,综合利用测井、岩心和三维地震等资料开展了高精度层序地层划分、沉积微相描述和优质储集层地震反演研究。建立了风南井区四级层序地层格架,明确了扇三角洲多期水进水退的充填过程,指出SSQ3和SSQ5是优质储集层的发育层系;识别出扇三角洲平原分流河道、河道间和扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相,指出扇三角洲平原是优质储集层发育相带;通过应用高分辨层序地层纵向边界和沉积相横向边界约束,进行分层相控叠后地震波阻抗反演,提升储集层预测精度,在SSQ3和SSQ5预测5个优质储集层发育区,提出3口井的井位建议,钻探均获工业油流。  相似文献   

气候变化对中国观鸟旅游的影响——基于鸟类物候变化的分析   总被引：2，自引：0，他引：2  

刘俊  黄莉  孙晓倩  李宁馨  张恒锦 《地理学报》2019,74(5):912-922

全球观鸟活动的规模达到了每年几千万人次,观鸟旅游已经成为世界野生动物观赏业的重要组成部分。气候变化改变了鸟类物候期及其空间格局,这不仅会影响观鸟者的旅游活动,还会进一步对观鸟旅游利益相关者的生计产生影响。监测并尽早地识别出这些影响,提醒利益相关者采取有效的适应策略意义重大。本文引入物候期这一气候变化的“指示器”来反映开展观鸟旅游的重要资源基础——鸟类活动时间以及栖息地格局的变化。通过对1980-2010年中国26个地区的98个物候序列的鸟类研究进行荟萃分析发现：中国鸟类离开、抵达、停留时间以及鸟类栖息地的格局都已经发生了改变。春季、夏季鸟类会提前离开或抵达,但在秋季它们的活动会延迟。鸟类停留的时间主要呈现延长的趋势。温度升高会使鸟类停留时间变长,对观鸟旅游的开展有利。中国低纬度地区和西部地区鸟类停留时间更长。鸟类栖息地的格局呈现出向北和向西迁移的特征。游客和景区工作人员均已感知到鸟类活动时间以及栖息地格局的变化对观鸟旅游产生的影响。  相似文献   

深渊着陆器坐底位置的精确测量和反演计算          下载免费PDF全文

陈瀚  丘学林  贺恩远  王元  陈传绪  陈俊 《地球物理学报》2019,62(5):1744-1754

深渊着陆器在下潜过程中,由于受到海流的影响,其坐底位置会偏离投放点,偏离量和偏离方向很难估计,而声学水下定位方法在深渊海区不太适用.通过在海面进行气枪十字放炮作业,利用炮点准确位置和时间信息,以及海底地震仪(Ocean Bottom Seismometer,OBS)记录的直达水波到时,对深渊着陆器的坐底位置进行精确测量可以提供有效定位数据.该方法对采集得到的数据进行预处理,使用蒙托卡洛方法结合最小二乘法,对万泉号着陆器实际坐底位置进行了反演校正,得到三个潜次的位置校正偏移量分别为211m、178m、861m,偏移方向各不相同,校正精度为±20m,比以往的定位精度大为提高.此外,该方法测量确定了三个海底标志物的精确位置,为未来万米无人或载人潜器提供了可靠的水下参考坐标.  相似文献