Climate-change driven increased flood magnitudes and frequency in the British uplands: Geomorphologically informed scientific underpinning for upland flood-risk management     

David J. Milan  Arved C. Schwendel 《地球表面变化过程与地形》2021,46(15):3026-3044

Upland river systems in the UK are predicted to be prone to the effects of increased flood magnitudes and frequency, driven by climate change. It is clear from recent events that some headwater catchments can be very sensitive to large floods, activating the full sediment system, with implications for flood risk management further down the catchment. We provide a 15-year record of detailed morphological change on a 500-m reach of upland gravel-bed river, focusing upon the geomorphic response to an extreme event in 2007, and the recovery in the decade following. Through novel application of two-dimensional (2D) hydrodynamic modelling we evaluate the different energy states of pre- and post-flood morphologies of the river reach, exploring how energy state adjusts with recovery following the event. Following the 2007 flood, morphological adjustments resulted in changes to the shear stress population over the reach, resulting in higher shear stresses. Although the proportion of shear stresses in excess of those experienced using the pre-flood digital elevation model (DEM) varied over the recovery period, they remained substantially in excess of those experienced pre-2007, suggesting that there is still potential for enhanced bedload transport and morphological adjustment within the reach. Although volumetric change calculated from DEM differencing does indicate a reduction in erosion and deposition volumes in the decade following the flood, we argue that the system still has not fully recovered to the pre-flood state. We further argue that Thinhope Burn, and other similarly impacted catchments in upland environments, may not recover under the wet climatic phase currently being experienced. Hence systems like Thinhope Burn will continue to deliver large volumes of sediment further down river catchments, providing new challenges for flood risk management into the future.  相似文献   

关于开展贵阳市新一轮城市地质工作的建议     

刘爱民  林树基 《贵州地质》2004,21(2):81-85

本文回顾了50年代以来贵阳城市地质工作的概况,建议贵阳市新的城市地质工作的开展宜早不宜迟,提出了下一步开展贵阳市地质工作的新思路、新理论、新方法及主要预期成果。  相似文献   

Solid–fluid transition modelling in geomaterials and application to a mudflow interacting with an obstacle     

Noémie Prime  Frédéric Dufour  Félix Darve 《国际地质力学数值与分析法杂志》2014,38(13):1341-1361

Given the contrasting behaviour observed for geomaterials, for example, during landslides of the flow type, this contribution proposes an original constitutive model, which associates both an elasto‐plastic relation and a Bingham viscous law linked by a mechanical transition criterion. This last is defined as the second‐order work sign for each material point, which is a general criterion for divergence instabilities. Finite element method with Lagrangian integration points is chosen as a framework for implementing the new model because of its well‐known ability to deal with both solid and fluid behaviours in large deformation processes. A first boundary model considering a sample of initially stable soil, a slope and an obstacle is performed. The results show the power of the constitutive model because the consistent evolution of initiation, propagation and arrest of the mudflow is described. A parametric study is led on various plastic and viscous parameters to determine their influence on the flow development and arrest. Finally, forces against the obstacle are compared with good agreement with those of other authors for the same geometry and a pure viscous behaviour. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

基于ArcGIS Runtime SDK for Android离线编辑关键技术应用研究   总被引：1，自引：0，他引：1  

任思思  张禹  郑磊  周亮 《测绘与空间地理信息》2017,40(7)

近年来,传统的外业调绘模式逐渐向内外业一体化模式转变。本文以地理国情内外业一体化系统为依托,重点研究了ESRI的离线编辑关键技术,介绍了基于ArcGIS Runtime SDK for Android实现的离线编辑功能,以面修形算法为例,在细粒度的几何编辑基础上实现了常见的外业编辑业务。  相似文献   

浅谈省级1∶10000基础地理信息数据更新工作方案     

李爽 《测绘与空间地理信息》2017,(2):117-119

1∶10 000地形图更新工作是省级基础测绘的重要组成部分,本文主要论述了1∶10 000地形图更新工作方案的制订过程,在充分分析了现有地理信息数据情况的前提下,合理制订更新目标、方法及技术方案,为"十三五"期间基础测绘工作的开展提供了重要的参考依据。  相似文献   

浅谈测绘工程监理内容及方法     

杨少愚 《测绘与空间地理信息》2017,(4)

测绘监理与测绘行业质量监督不同,测绘监理注重生产的全过程,控制测绘生产过程中各个工序的质量,从而保障最终测绘成果的质量;测绘行业质量监督则是代表政府行使对测绘项目进行监督的行为。因此,两者在工作范围、工作性质以及工作深度等方面存在差别。但是两者同时又有统一的关系,也就是都为保障测绘成果质量,更好地服务保障经济社会发展采取的保障措施。现今在国内已有很多项目引入了监理机制,但尚没有形成一套完善有效的测绘监理行业规范。笔者根据多年在广东、海南、新疆等地区从事监理工作的实际经验,结合工程监理中的部分内容和方法,总结出了一套较为完善有效的测绘工程监理方案。  相似文献   

Global city and precarious work of migrants in China: a survey of seven cities     

Zhongwei Sun 《Urban geography》2017,38(10):1479-1496

Drawing on data from a sample of 2,518 migrant workers from seven cities in China, this paper examines how precarious work of migrants varies across different types of cities. The research finds that compared with their counterparts in the non-global cities, migrant workers in Shanghai experience lower levels of precarity in their jobs. Additionally, with regards to different aspects of precariousness of work, Shanghai performs particularly better on providing labor contracts and social insurances. Contrary to the standard “Global City” hypothesis, it seems that in a developing country such as China, globalization is more likely to improve the institutionalization and standardization of industrial relationships rather than decay them.  相似文献   

经纬仪观测工作平台的建立     

邓幼俊  陈玲强 《天文研究与技术》1999,(4)

本软件项目于１９９７ 年底最后完成。提高了人卫系统各台站观测的自动化程度, 大幅度减少了观测员各种繁琐的数据处理工作。它包括ｅ －ｍａｉｌ 收发报, 数据采集和处理, 静态系统差测定等功能, 可应用于人卫系统的各个观测台站。  相似文献   

《伤寒论》是中医辨治疫病的奠基之作（一）          下载免费PDF全文

袁长津 《应用海洋学学报》2023,39(6):1

东汉张仲景所著《伤寒杂病论》一书中,虽没有后世疫病之名目,却真实记载了大量辨治疫病之证治方药的条文及案例经验。笔者抚今追古,重温经典,结合自己多年的临床经验及其体认,并引证了当代诸多医家名宿之论,认为《伤寒论》堪称我国古代疫病防治的奠基之作。《伤寒论》虽以辨治寒疫及寒湿疫为主,但也包括湿热类、热毒类及瘀毒类疫病的证治。其所论及疫病的类型及疑似病种,寒湿类疫病主要包括：流行性感冒及其并发呼吸道和消化道感染,流行性脑脊髓膜炎,流行性腹泻（寒性）及寒性霍乱,流行性出血热等急性传染病;温热类疫病最为确定的是“黄疸”和“下利”,其证候与现代所谓急性病毒肝炎和急性细菌性痢疾基本相同;该书还开示了辨治热毒疫、瘀毒疫之法门,对后世影响深远。笔者还从《伤寒论》全篇整体分析,体悟到张仲景以“正邪博弈”为核心理念辨治外感疫病的思想,分别采取以祛邪为主、以扶正为主或以祛邪扶正并重的治则大法;并开创了病证结合、以辨证论治为主的中医诊疗模式。  相似文献   

深度神经网络拾取地震P和S波到时   总被引：8，自引：0，他引：8       下载免费PDF全文

于子叶  储日升  盛敏汉 《地球物理学报》2018,61(12):4873-4886

从地震波形数据中快速准确地提取各个震相的到时是地震学中的基础问题.本文针对上述问题提出了利用深度神经网络拾取到时的新方法,建立了用于地震到时提取的17层Inception深度网络模型,在对原始三分量数据进行高通滤波和归一化处理后输入网络直接输出到时信息.整个过程基于神经网络自适应提取波形特征,自动输出结果.通过对100组加了不同强度的噪声数据进行了可靠性检验,相比于其他方法神经网络方法对于噪声具有较高的容忍度以及稳定性,并且与地震目录数据有较高的相似性.相比于AR-AIC+STA/LTA,深度神经网络虽然运算速度稍慢,但整个过程不需设定时窗与阈值,同时具有更高的可用性,并且可以迭代升级以提高精度.此方法作为人工智能方法,为波形到时拾取提供了新思路.  相似文献