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川江流域生态地貌系统稳定性影响因素 被引量:2
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作者 李立华 刘淑珍 何毓成 《山地研究》 CSCD 1992年第2期116-122,共7页
川江流域片蚀与地表物质组成、坡度和坡长关系密切,且明显受地貌类型控制;沟蚀与森林覆盖率呈负相关,而和人口密度呈正相关;重力侵蚀在盆周山区和流域西北部高山中山区危害严重;人类消极活动在盆中丘陵区因人口稠密而活跃。这四个因素... 川江流域片蚀与地表物质组成、坡度和坡长关系密切,且明显受地貌类型控制;沟蚀与森林覆盖率呈负相关,而和人口密度呈正相关;重力侵蚀在盆周山区和流域西北部高山中山区危害严重;人类消极活动在盆中丘陵区因人口稠密而活跃。这四个因素的发生发展制约着本流域生态地貌系统的稳定性。 展开更多
关键词 川江流域 生态地貌系统 稳定性
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Adapting cities to sea level rise: A perspective from Chinese deltas 被引量:3
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作者 CHENG He-Qin CHEN Ji-Yu 《Advances in Climate Change Research》 SCIE CSCD 2017年第2期130-136,共7页
In recent years, intensifying waterlogging, salt water intrusion, wetland loss, and ecosystem degradation in Chinese delta cities and adjacent regions have generated the pressing need to create an urban form that is s... In recent years, intensifying waterlogging, salt water intrusion, wetland loss, and ecosystem degradation in Chinese delta cities and adjacent regions have generated the pressing need to create an urban form that is suited to both current and future climates incorporating sea level rise. However, adaptation planning uptake is slow. This is particularly unfortunate because patterns of urban form interact with mean sea level rise (MSLR) in ways that reduce or intensify its impact. There are currently two main barriers that are significant in arresting the implementation of adaptation planning with reference to the MSLR projections composed of geomorphologic MSLR projections and eustatic MSLR projections from global climate warming, and making a comprehensive risk assessment of MSLR projections. The present review shows recent progresses in mapping MSLR projections and their risk assessment approaches on Chinese delta cities, and then a perspective of adapting these cities to MSLR projections as following six aspects. 1) The geomorphologic MSLR projections are contributed by the natural tectonic subsidence projections and the MSLR projections by anthropogenic geomorphologic change. The former needs to be updated in a global framework. The latter is accumulated by land subsidence from underground water depletion, water level fall caused by the erosion of riverbeds from a sediment supply decline attributed to the construction of watershed dams, artificial sand excavation, water level raise by engineering projects including land reclamation, deep waterway regulation, and fresh water reservoirs. 2) Controlling MSLR projections by anthropogenic geomorphologic changes. 3) The IPCC AR5 RCPs MSLRs scenarios are expected to be projected to the local eustatic MSLR projections on the Chinese deltas. 4) The MSLR projections need to be matched to a local elevation datum. 5) Modeling approaches of regional river-sea numerical with semi- analytical hydrodynamics, estuarine channel network, system dynamics and adaptation points are perspective. 6) Adaptation planning to MSLR projections requires a comprehensive risk assessment of the risk of flood, fresh water supply shortage, coastal erosion, wetland loss, siltation of ports and waterway in Chinese delta cities and adjacent regions. 展开更多
关键词 Mean sea level rise projections Natural tectonic subsidence Climate warming Local elevation datum Anthropogenic geomorphologic change Adaptation tipping point
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Regional hard coral distribution within geomorphic and reef flat ecological zones determined by satellite imagery of the Xisha Islands,South China Sea 被引量:3
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作者 左秀玲 苏奋振 +3 位作者 赵焕庭 张君珏 王琦 吴迪 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期501-514,共14页
Coral reefs in the Xisha Islands (also known as the Paracel Islands in English), South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geo... Coral reefs in the Xisha Islands (also known as the Paracel Islands in English), South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geomorphic and ecological zones, essential for reefs management in the context of global warming and ocean acidification, is not well documented. We analyzed data from field surveys, Landsat-8 and GF-1 images to map the distribution of hard coral within geomorphic zones and reef fiat ecological zones. In situ surveys conducted in June 2014 on nine reefs provided a complete picture of reef status with regard to live coral diversity, evenness of coral cover and reef health (live versus dead cover) for the Xisha Islands. Mean coral cover was 12.5% in 2014 and damaged reefs seemed to show signs of recovery. Coral cover in sheltered habitats such as lagoon patch reefs and biotic dense zones of reef flats was higher, but there were large regional differences and low diversity. In contrast, the more exposed reef slopes had high coral diversity, along with high and more equal distributions of coral cover. Mean hard coral cover of other zones was 〈10%. The total Xisha reef system was estimated to cover 1 060 km2, and the emergent reefs covered -787 km2. Hard corals of emergent reefs were considered to cover 97 km2. The biotic dense zone of the reef flat was a very common zone on all simple atolls, especially the broader northern reef flats. The total cover of live and dead coral can reach above 70% in this zone, showing an equilibrium between live and dead coral as opposed to coral and algae. This information regarding the spatial distribution of hard coral can support and inform the management of Xisha reef ecosystems. 展开更多
关键词 coral reef geomorphic zone remote sensing Xisha Islands South China Sea
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