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941.
942.
Zhongqian?TangEmail author Shanzhen?Yi Chunhua?Wang Yangfan?Xiao 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(3):701-714
Flood risk management can be enhanced by integrating geographic information system (GIS) with multi-criteria decision analysis (MCDA). However, the conventional, deterministic MCDA methods ignore uncertainty in the decision-making process and fail to account for local variability in criteria values and preferences. Therefore, a spatially explicit MCDA model which effectively incorporates spatial heterogeneity is required. In this paper, a probabilistic or stochastic MCDA method which incorporates the uncertainty into a local weighted linear combination (WLC) was utilized to evaluate flood susceptibility; and an application case in Gucheng County, Central China, was developed. A GIS database of geomorphological and hydro-meteorological criteria contributing to flood susceptibility analysis was constructed using six conditioning factors: digital elevation model (DEM), slope (SL), maximum three-day precipitation (M3DP), topographic wetness index (TWI), distance from the river (DR), and Soil Conservation Service Curve Number (SCS-CN). The results of local WLC were compared with those of the global WLC. It shows that the local WLC model can provide much more valuable information about the spatial patterns of criterion values, ranges, weights, trade-offs and overall scores, whereas the global WLC can only depict the spatial distribution of criterion values and overall scores. The local WLC can also help to prioritize the most susceptible locations within a neighborhood when navigating the disaster assistance process. Moreover, the uncertainty analysis of criteria weights increases the degree of confidence in the model output. It is concluded that the presented approach can provide more insights and understanding of the nature of the flood susceptibility than global WLC. 相似文献
943.
944.
通过分析地震应急救援工作中对灾情信息的需求,提出了“地震应急灾情”的概念,设计了基于12322平台的江苏省地震应急灾情速报系统。本文详细介绍了该系统的设计框架、基本功能和应用效果。系统主要包括短信和微信两大模块,短信模块主要面向非地震系统人员,通过手机短信形式向社会灾情速报员发送灾情邀请短信,灾情速报员只需简单回复灾情代码“1”—“4”即可。微信模块主要面向地震系统工作人员,通过微信企业号“苏震12322”自动推送地震信息并完成灾情收集工作。经过近1年的试运行,系统能够在震后迅速完成灾情信息的收发与数据处理工作,并以“天地图”为地理底图实时直观地展示已上报的灾情信息。 相似文献
945.
Oceanic plate subduction history in the western Pacific Ocean: Constraint from late Mesozoic evolution of the Tan-Lu Fault Zone 总被引:4,自引:0,他引:4
Guang Zhu Cheng Liu Chengchuan Gu Shuai Zhang Yunjian Li Nan Su Shiye Xiao 《中国科学:地球科学(英文版)》2018,61(4):386-405
The NE- to NNE-striking Tan-Lu Fault Zone (TLFZ) is the largest fault zone in East China, and a typical representative for the circum-Pacific tectonics. Its late Mesozoic evolution resulted from subduction of the Paleo-Pacific Plate, and can be used for indication to the subduction history. The TLFZ reactivated at the end of Middle Jurassic since its origination in Middle Triassic. This phase of sinistral motion can only be recognized along the eastern edge of the Dabie-Sulu orogenis, and indicates initiation of the Paleo-Pacific (Izanagi) Plate subduction beneath the East China continent. After the Late Jurassic standstill, the fault zone experienced intense sinistral faulting again at the beginning of Early Cretaceous under N-S compression that resulted from the NNW-ward, low-angle, high-speed subduction of the Izanagi Plate. It turned into normal faulting in the rest of Early Cretaceous, which was simultaneous with the peak destruction of the North China Craton caused by backarc extension that resulted from rollback of the subducting Izanagi Plate. The TLFZ was subjected to sinistral, transpressive displacement again at the end of Early Cretaceous. This shortening event led to termination of the North China Craton destruction. The fault zone suffered local normal faulting in Late Cretaceous due to the far-field, weak backarc extension. The late Mesozoic evolution of the TLFZ show repeated alternation between the transpressive strike-slip motion and normal faulting. Each of the sinistral faulting event took place in a relatively short period whereas every normal faulting event lasted in a longer period, which are related to the subduction way and history of the Paleo-Pacific Plates. 相似文献
946.
Jiahui Yao Linxiang Xiao Mengmeng Gou Chao Li Ergang Lian Shouye Yang 《中国科学:地球科学(英文版)》2018,61(4):473-482
This paper briefly introduces the history of the study of the Pacific decadal oscillation (PDO) and explores the relationship between the PDO and sediment grain size from two typical sediment cores from the lower Changjiang (Yangtze River) and Huanghe (Yellow River) estuaries. It is found that the median grain sizes of both cores exhibit relatively high correlation with the PDO. This is because the PDO causes interdecadal variability of precipitation in the East Asia Monsoon region, thus changing the hydrodynamics in both the Changjiang and Huanghe catchments, eventually resulting in variation of sediment grain size. Our analysis also revealed that during different phases of the PDO, the sediment grain size of the Changjiang and Huanghe estuaries showed different variations in cold and warm PDO phases. This is related to movement of the precipitation center driven by the shift in different PDO phases. Moreover, we compared more high resolution geological proxies with the PDO, including stalagmites and tree rings, in East China over the past century. The results indicate that variations of studied geological proxies are generally well correlated with the PDO but have some differences. Finally, longer variations of sediment grain sizes in the Changjiang and Huanghe estuaries are compared with a reconstructed PDO over the last 200 years; sediment grain sizes were still correlated with the PDO, implying that sediment grain size may be used as a new proxy for studying the long-term behavior of the PDO. This result supports previous knowledge of the PDO impact on East China climate evolution and offers a new proxy for further PDO study. Our study will improve paleoenvironment reconstruction in East China on a decadal time scale and benefit future climatic predictions. 相似文献
947.
Wei Xiao Yufei Qian Xuhui Lee Wei Wang Mi Zhang Xuefa Wen Shoudong Liu Yongbo Hu Chengyu Xie Zhen Zhang Xuesong Zhang Xiaoyan Zhao Fucun Zhang 《中国科学:地球科学(英文版)》2018,61(10):1523-1532
The kinetic fractionation of open-water evaporation against the stable water isotope H_2 ~(18)O is an important mechanism underlying many hydrologic studies that use ~(18)O as an isotopic tracer. A recent in-situ measurement of the isotopic water vapor flux over a lake indicates that the kinetic effect is much weaker(kinetic factor 6.2‰) than assumed previously(kinetic factor14.2‰) by lake isotopic budget studies. This study investigates the implications of the weak kinetic effect for studies of deuterium excess-humidity relationships, regional moisture recycling, and global evapotranspiration partitioning. The results indicate that the low kinetic factor is consistent with the deuterium excess-humidity relationships observed over open oceans.The moisture recycling rate in the Great Lakes region derived from the isotopic tracer method with the low kinetic factor is a much better agreement with those from atmospheric modeling studies than if the default kinetic factor of 14.2‰ is used. The ratio of transpiration to evapotranspiration at global scale decreases from 84±9%(with the default kinetic factor) to 76±19%(with the low kinetic factor), the latter of which is in slightly better agreement with other non-isotopic partitioning results. 相似文献
948.
Abu?Sadat?Md?Sayem Zhengtang?GuoEmail author Haibin?Wu Chunxia?Zhang Fan?Yang Guoqiao?Xiao Zhilin?He 《中国科学:地球科学(英文版)》2018,61(9):1292-1305
The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major advances in the last few decades,the evolutionary history and possible mechanisms of Eocene climate change in the northeastern Tibetan Plateau remain unclear.The Xining Basin in the northeastern Tibetan Plateau contains a continuous sequence of Early to Late Eocene non-marine sediments which provides the opportunity to resolve long-term climate changes during this period. In this study, we report the results of analyses of lithofacies, sediment color and geochemistry of bulk samples collected from the Xijigou section of the Xining Basin. An abrupt lithofacies change between the Early(~52–40 Ma) and Late Eocene(~40–34 Ma) indicates a change in the depositional environment from a shallow lake to a playa lake in response to a significant climatic shift. During ~52–40 Ma,higher values of sediment redness(a*), redness/lightness(a*/L*) and higher modified Chemical Index of Weathering(CIW′)indicate a relatively warm and humid climate, while from ~40–34 Ma the lower values of a*, a*/L*and lower CIW′ imply subhumid to semi-arid climatic conditions. The paleoclimatic records indicate a long-term(~52–34 Ma) trend of decreasing chemical weathering, consistent with global climate change. An abrupt sharp excursion of the proxy records during ~42–40 Ma suggests a relatively brief warm interval, corresponding to the Middle Eocene Climatic Optimum(MECO). We suggest that global cooling substantially reduced humidity in inner Asia, resulting in sub-humid to semi-arid climatic conditions after 40 Ma in the Xining Basin, which may have been responsible for the long-term trend of decreasing chemical weathering during the Eocene. 相似文献
949.
Crustal deformation shows different patterns at different depths due to changes in the physical properties of rock.Tectonic levels can be defined based on the geometry and deformation mechanisms of crustal deformation patterns. Nujiang Gorge, with a high riverbed drop, great erosion depth, and strong deformation, has rock exposures at different tectonic levels and thus provides an ideal lab for deformation study. This paper takes the Nujiang Gorge from Chawalong to Fugong as the object to identify structural deformation patterns at different depths through field study and deformation analysis. At depth, the primary form of deformation is flow deformation, as shown on the outcrops at Maji. Ductile shear deformation can be found in many outcrops within the study region, e.g., the Gaoligong dextral shear zone and Puladi-Songta sinistral shear zone that lie to the south and north of Maji, respectively. Further to the north of Puladi, the dominated deformation pattern is similar fold and dense sub-vertical foliation. In addition, brittle faults, as evidence of shallow deformation, can be seen overprinting on the deeper deformation features all over the region. Based on those observations, this paper identifies four tectonic levels from depth to the surface: flow deformation, ductile shear deformation, similar fold, and brittle fault deformation, all of which result from the NEE-SWW compressive stress field. Further evidence from studies on the region′s thermal evolution and regional tectonics suggests that the development of different tectonic levels is closely linked to the discrepant uplift or denudation since the Miocene(~21 Ma). 相似文献
950.