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According to calculation results of ocean chlorophyll concentration based on SeaWiFS data by SeaBAM model and synchronous ship-measured data, this research set up an improved model for CaseⅠand CaseⅡwater bodies respectively. The monthly chlorophyll distribution in the East China Sea in 1998 was obtained from this improved model on calculation results of SeaBAM. The euphotic depth distribution in 1998 in the East China Sea is calculated by using remote sensing data of K490 from SeaWiFS according to the relation between the euphotic depth and the oceanic diffuse attenuation coefficient. With data of ocean chlorophyll concentration, euphotic depth, ocean surface photosynthetic available radiation (PAR), daily photoperiod and optimal rate of daily carbon fixation within a water column, the monthly and annual primary productivity spatio-temporal distributions in the East China Sea in 1998 were obtained based on VGPM model. Based on analysis of those distributions, the conclusion can be drawn that there is a clear bimodality character of primary productivity in the monthly distribution in the East China Sea. In detail, the monthly distribution of primary productivity stays the lowest level in winter and rises rapidly to the peak in spring. It gets down a little in summer, and gets up a little in autumn. The daily average of primary productivity in the whole East China Sea is 560.03 mg/m2/d, which is far higher than the average of subtropical ocean areas. The annual average of primary productivity is 236.95 g/m2/a. The research on the seasonal variety mechanism of primary productivity shows that several factors that affect the spatio-temporal distribution may include the chlorophyll concentration distribution, temperature condition, the Yangtze River diluted water variety, the euphotic depth, ocean current variety, etc. But the main influencing factors may be different in each local sea area. 相似文献
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The Yudonghe landslide, located in western Hubei Province of China, consists of eastern and western subunits as well as a main landslide mass with upper and lower slip surfaces. As an important landslide close to Shuibuya Dam on the Qing River, its stability is crucial, as the slide might reactivate because of a change in ground-water level caused by filling of the Shuibuya Reservoir. Existing weakness zones, growth of ruptures, the downslope attitude of geologic strata, and water infiltration, which reduced the strength of rocks and soils, have been found to be the most important factors contributing to the Yudonghe landslide. With regard to the landslide processes, it can be noted that the original large-scale slide activity was due to erosion by the Qing River, the second sliding resulted from the fall of blocks from the head scarp, and the final activity was the growth of the eastern and western secondary slides. A base failure was the main type of slope movement, however, it was obvious that more than one sliding event occurred, as inferred from striations and fractures detected by microstructure analysis of soils along the failure surfaces. Slope instability was evaluated by the method of Back Propagation Neural Networks (BPNN), in which a four-layer BPNN model with five input nodes, two hidden layers, and two output nodes was constructed using a training data set of landslide samples throughout the Qing River area. The predicted results of this analysis showed that the factor of safety was 1.10, which indicates that the Yudonghe landslide is currently in a marginally stable condition. 相似文献
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厦门市海沧区北市花岗岩矿滑坡发生于2004年10月30日14时。滑坡位于呆场的西端帮顶部的第四系填土和淤泥质土层中,滑体将该区域原设的抗滑桩剪断、拔出、推移,土石迅速越过矿区运输公路,塌落到采场工作面,将正在作业的2名工人和生产设备掩埋。滑坡宽度约60m,最大垂直厚度约14m,总体积约13000m^3。由于滑坡对原有防护体系的破坏,根据滑体调查和极限平衡计算结果,滑坡处于不稳定状态,直接威胁着整个采场设备和未来生产的安全。必须对北市花岗岩矿滑坡进行专项治理。滑坡宜采用治水、削坡减载和支挡相结合的综合治理措施。 相似文献
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基于不同人口需要而进行的人类活动对“三江并流”区的地理环境产生了巨大影响,形成了独具特色的人地作用机制。这一作用机制一方面对“三江并流”世界遗产的保护构成了威胁,但另一方面,通过人口生态生产,实现人口数量、质量、结构和分布的生态化,改进人类活动,也可优化“三江并流”区的地理环境,保护“三江并流”世界遗产,实现该地区的可持续发展。 相似文献
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笔者等对《中国矿产地质志·华南洋—滨太平洋构造演化与成矿》一书(2020)厘定的战略矿产资源居于重要地位的华夏成矿省作些简要论述:① 该成矿省处于古华南洋成矿域与滨太平洋成矿域强烈复合地带,历经早前寒武世克拉通—华南洋—华南裂谷系—陆表海—大陆的发展演化,又受到多期造山特别是空前强烈的燕山期陆内活化造山,并且是一个世界级钨地球化学块体,构成了优越的成矿基因;② 主要成矿特征:包括华南洋及其陆缘弧盆残体成矿,南华间冰期与冰后期大规模沉积成矿,多期大规模S型岩浆以钨为首的有色、铀、贵金属、非金属成矿,I型岩浆以铜为首的铁、有色、贵金属成矿以及钦杭成矿带超大矿床集群与“深地”找矿之眼等;③ 燕山运动岩浆与成矿“核幔式”时空演化规律以及多体系复合构造格局与陆洋左行扭动与洋壳俯冲为主导并有板内挤压、地壳蠕散相复合的动力学机制。 相似文献
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本文采用对比分析与归纳分析法,在明确全民所有自然资源资产管理考核评价机制定位的基础上,充分借鉴和参考现有相关考核评价制度的设计思路,围绕“考核谁、谁来考、怎么考、考什么、结果怎么定、结果怎么用”等关键问题,从考核评价对象和实施主体、考核评价方式和实施、考核评价结果应用、考核评价内容和指标体系构建、考核评价结果评定方法等方面,提出构建全民所有自然资源资产管理考核评价机制和方法的思路,为推进生态文明建设和自然资源资产产权制度改革提供支撑。 相似文献