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131.
132.
Kuei-Hsien Liao 《Natural Hazards》2014,71(1):723-750
Despite massive investment in flood control infrastructure (FCI), neither cities nor rivers have been well served—flooding continues to challenge cities around the world, while riverine ecosystems are degraded by FCI. Although new flood hazard management concepts have shifted the focus away from FCI, many cities continue to count on FCI to prevent flood damage. It is assumed that existing built-up areas can only count on FCI, as large-scale retreat is often impossible. However, flood adaptation—retrofitting the built environment to prevent damage during flooding—as an option is often ignored. This paper argues against the continual use of FCI to prevent flood damage by reviewing FCI’s established problems. The paper examines human–river interactions associated with FCI, focusing on the feedback mechanisms in the interactions, with a case study on the Lower Green River (LGR) valley in King County, Washington, USA. An urban ecology research model is employed to organize the case study, where interactions between floodplain urbanization, FCI, flow and sediment changes, flood risk, and riverine ecosystem are explored and two feedback mechanisms—river adjustment and flood risk perception—are explicitly addressed. The resulting complex dynamics, in terms of cross–scale interactions, emergence, nonlinearity, and surprises, are synthesized and limitations of FCI outlined. Flood adaptation is explored as a plausible alternative to flood control to nurture flood resilience. A management scenario of flood adaptation for the City of Kent—the largest municipality in the LGR valley—is developed to discuss the implications of flood adaptation on flood risk and river restoration. 相似文献
133.
斑岩型铜钼矿床除主要成矿元素Cu,Mo外,还往往共(伴)生Re,Co,Au,Ag等重要元素,综合回收利用共(伴)生金属具有重大资源及环境效益。通过研究斑岩型铜钼矿床中共(伴)生元素Re,Co,Au,Ag的品位、储量、赋存状态及分布规律,认为Co主要以类质同象形式赋存于黄铁矿中,其分布与黄铁矿密切相关,通常浓集于绢英岩化带外侧;Au,Ag主要以自然金、银与金银系列矿物的形式产出,Au,Ag在不同硫化物中的含量、颗粒粒度以及赋存形式差异很大,Au在各蚀变带均有可能富集,但主要浓集区域是钾化带与石英-绢云母化带;Ag在早期主要以Cu-Ag-Au的形式富集于绢英岩化带,晚期以Pb-Zn-Ag形式赋存于青磐岩化带;Re的分布与绢云母化带的辉钼矿密切相关。 相似文献
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135.
A two‐dimensional (2D) finite‐difference shallow water model based on a second‐order hybrid type of total variation diminishing (TVD) approximate solver with a MUSCL limiter function was developed to model flooding and inundation problems where the evolution of the drying and wetting interface is numerically challenging. Both a minimum positive depth (MPD) scheme and a non‐MPD scheme were employed to handle the advancement of drying and wetting fronts. We used several model problems to verify the model, including a dam break in a slope channel, a dam break flooding over a triangular obstacle, an idealized circular dam‐break, and a tide flow over a mound. Computed results agreed well with the experiment data and other numerical results available. The model was then applied to simulate the dam breaking and flooding of Hsindien Creek, Taiwan, with the detailed river basin topography. Computed flooding scenarios show reasonable flow characteristics. Though the average speed of flooding is 6–7 m s?1, which corresponds to the subcritical flow condition (Fr < 1), the local maximum speed of flooding is 14·12 m s?1, which corresponds to the supercritical flow condition (Fr ≈ 1·31). It is necessary to conduct some kind of comparison of the numerical results with measurements/experiments in further studies. Nevertheless, the model exhibits its capability to capture the essential features of dam‐break flows with drying and wetting fronts. It also exhibits the potential to provide the basis for computationally efficient flood routing and warning information. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
136.
Acta Geotechnica - The critical state of anisotropically consolidated clay is not well captured by the classical anisotropic bounding surface plasticity model without considering the real... 相似文献
137.
根据岩心观察、薄片鉴定和图像分析, 对西科1井第四纪发育的典型暴露面及其附近的岩石类型、成岩作用和孔隙类型进行了系统的分析.研究表明: 典型暴露面(埋深68.75~70.24 m)附近的岩石类型为骨架灰岩和泥粒灰岩, 成岩作用类型包括溶解作用、胶结作用、泥晶化作用和新生变形作用, 孔隙类型主要为粒间孔和粒间溶孔、粒内孔及粒内溶孔、生长骨架孔及其溶孔、铸模孔和晶间溶孔.碳酸盐矿物的悬垂状产状、生物体腔孔充填物的方解石化和普遍发育的溶解作用指示该深度段遭受了大气水淋滤的强烈改造. 相似文献
138.
Zeng Jingjing Qu Jiansheng Pei Huijuan Dong Liping Liao Qin Liu Yanfei Zhang Zhiqiang 《地球科学进展》2015,30(11):1210-1217
The international climate change negotiation has been carried out over 20 years. The issue of climate change has shifted from a scientific question into a complex political matter which is related to the sustainable development of mankind. Based on the overview of major processes and stages of international climate conferences, this paper analyzed the key measures that major countries have taken to address climate change, as well as the primary tasks of Paris climate conference and recent international actions. The recent international climate policy issues were also analyzed in order to provide suggestions for China’s activel participation in the development of a new round of international climate change system. 相似文献
139.
140.
西南区域中尺度数值模式预报性能及其与天气过程关系初探 总被引:2,自引:1,他引:1
本文以探空站和自动站实测资料为检验参考,通过主客观检验GRAPES和WRF模式在西南地区的初始分析场和预报场,一定程度揭示出模式在西南地区的初值质量、动力框架性能和降水参数化效果。GRAPES在西南地区的位势高度、风速、风向初值质量都不同程度好于WRF,但进入预报阶段,GRAPES位势高度、温度均方根误差以比WRF更高的斜率随时效增长,GRAPES对西南地区的500 hPa高度场预报呈现系统性偏低,而WRF对西南地区高度预报的正误差概率比较高;分类天气过程检验表明,GRAPES对低涡、切变过程的初始分析质量好于WRF,但进入预报阶段,WRF对低槽、低涡和切变三类天气过程的低值系统预报正确率都高于GRAPES,这一定程度反映出WRF的模式性能好于GRAPES;分类天气过程降水预报检验表明,低涡过程降水预报难于低槽过程。GRAPES对低涡过程的降水预报能力较低,WRF预报能力最低的是切变过程。这与模式对分类天气过程中低值系统预报能力一致,这一定程度表明两个模式的降水参数化效果水平相当。 相似文献