Fractional vegetation cover estimation based on soil and vegetation lines in a corn-dominated area

An automatic fractional vegetation cover (FVC) estimation method based on image characteristics in an agricultural region was proposed in this study to remove the empiricism in determining the key parameters of empirical methods. The proposed method automatically determined the soil and vegetation lines in the two-dimensional space of the red and blue band reflectances, which involved an iterative soil and vegetation pixels selection procedure, and then estimated FVC of a pixel based on its distances from the soil and vegetation lines. The accuracy assessment using field survey data indicated that the performance of the proposed method (R² = 0.69, RMSE = 0.072, Bias = 0.014) was comparable with several commonly used empirical methods. Therefore, it was indicated that the proposed method could effectively estimate FVC in the corn-dominated region.     

基于协同理论的旅游综合体演化过程与机制研究——以杭州西溪国家湿地公园为例

选取杭州西溪国家湿地公园作为案例地,引用协同理论为指导,探讨了旅游综合体的演化过程与机制,认为西溪国家湿地公园是由多要素组成的协同系统,经历了旅游产业要素“集聚-共生-融合”的演化过程,萌芽、成长和完善3个阶段集聚的分别是传统旅游业态要素、新兴旅游业态要素和创新旅游业态要素。演化本质是协同系统序参量的变化,不同演化阶段序参量各异,萌芽阶段体现为要素集聚,受外部经济效益驱动;成长阶段体现为要素共生,受内部要素结构调整驱动;完善阶段体现为要素融合,受创新驱动。演化动力是要素间的非线性作用,通过系统内部与外部的能量交换及子系统间相互作用所形成的反馈机制来实现。选取房价作为指标,采用均质与非均质空间比较法测定了西溪国家湿地公园的空间溢出效应。旅游业与相关产业协同创新是西溪国家湿地公园发展模式的主要特征,具体表现为以优良的资源禀赋和广阔的市场为基础,以旅游业为核心,吸引相关产业要素集聚,形成共生和融合效应,发展过程中注重外部物质能量交换和内部自组织调控。     

Optimal Precursors Triggering the Kuroshio Extension State Transition Obtained by the Conditional Nonlinear Optimal Perturbation Approach

In this study, the initial perturbations that are the easiest to trigger the Kuroshio Extension(KE) transition connecting a basic weak jet state and a strong, fairly stable meandering state, are investigated using a reduced-gravity shallow water ocean model and the CNOP(Conditional Nonlinear Optimal Perturbation) approach. This kind of initial perturbation is called an optimal precursor(OPR). The spatial structures and evolutionary processes of the OPRs are analyzed in detail. The results show that most of the OPRs are in the form of negative sea surface height(SSH) anomalies mainly located in a narrow band region south of the KE jet, in basic agreement with altimetric observations. These negative SSH anomalies reduce the meridional SSH gradient within the KE, thus weakening the strength of the jet. The KE jet then becomes more convoluted, with a high-frequency and large-amplitude variability corresponding to a high eddy kinetic energy level; this gradually strengthens the KE jet through an inverse energy cascade. Eventually, the KE reaches a high-energy state characterized by two well defined and fairly stable anticyclonic meanders. Moreover, sensitivity experiments indicate that the spatial structures of the OPRs are not sensitive to the model parameters and to the optimization times used in the analysis.     

黄海原环虫的研究Ⅰ——原(虫耑)虫科

原环虫(Archiannelids)中除去囊须虫属(Saccocirrus)等个体稍大外,余均为小型底栖生物(Meiobenthos).1962年以来,我们在黄海青岛沿岸采到5种原环虫.本文第一作者等曾就其中单殖囊须虫(Saccocirrus gabriellae Marcus*)作过初步报告;这里再根据日本北方的色丹岛、美国旧金山和我国黄海等海区标本,以及室内观察结果,对其不同种群间的变异和个体生殖发育情况作新的介述.很久以来普遍认为原环虫是环节动物门的一个纲,系比较原始的环虫.     

Recent research progress and prospects in tourism geography of China

Based on a large number of domestic literature reviews with related research abroad, academic standards and issues awareness have been intensified in domestic tourism geography, disciplinary consciousness and innovation enhancement. Hence, some valuable achievements have been made in the areas of tourism resources, tourism regional system, the spatial structure of tourism, tourism flow, ecotourism, tourism industry, tourism planning and tourism impacts, which strengthened the traditional advantages of research, expanded new areas of research and made research trends diverse. Meanwhile, with innovation of research methods, tourism geography in China is getting more and more internationally-oriented and reflecting Chinese characteristics. Research trends of China’s tourism geography are prospected: 1) Catering to national strategic needs, persisting problem-oriented, strengthening the metatheoretical research, and building Chinese “localization” of theory of tourism geography and method system. 2) Introducing and assimilating foreign theories and research methods, while focusing on explaining new tourism phenomena and problems in the domestic socio-economic background. 3) Concerning about the new regional spatial processes of demographic process, social process, and spatial process in new tourism trend. 4) Exploring interactive process and mechanism of man-land relationship and new models to develop territorial space under the tourism impacts. 5) Exploring important research issues of tourism geography in global, national, regional and local scales, from the point of view of spatial differentiation, scale transformation, interaction of man and nature, creating tourism geography interpretation system based on “process-structure-mechanism” of China. 6) Building theoretical system actively, while strengthening application-oriented research, and focusing on tourism poverty alleviation, tourism and heritage protection, national parks’ construction and other hot issues. Faced with econometrics research boom, we should return to rational thinking, using big data scientifically, while paying attention to the important role of qualitative evaluation in future research.     

Trade-offs between carbon sequestration,soil retention and water yield in the Guanzhong-Tianshui Economic Region of China

Natural ecosystems provide human society with very important products and services. With the rapid increase in population and the over-exploitation of natural resources, humans are continually enhancing the production of some services at the expense of others. This paper estimates changes in ecosystem services, and the relationship between these services in the Guanzhong-Tianshui Economic Region of China. These ecosystem changes are of great significance to the sustainable development of this economic region. The concept of production possibility frontier (PPF) is applied to evaluate the trade-offs and synergy between carbon sequestration, water yield and soil retention. Three land use strategy scenarios–planning, exploitation and protection–are applied to evaluate potential changes in ecosystem services. This study reveals noticeable trade-offs between carbon sequestration, soil retention and water yield, with synergy between carbon sequestration and soil retention. There are synergies between carbon sequestration, water yield and soil retention in the three scenarios. The protection scenario is the most favourable land use strategy for regulating ecosystem service capacity. This scenario results in the highest carbon sequestration, water yield and soil retention. The results could have implications for natural capital and ecosystem services planning, management and land use decision-making.     

“双液注浆法”在基坑堵漏中的应用研究

双液注浆法是在止水帷幕的渗漏处钻孔,找到基坑止水帷幕的渗漏通道,把一定浓度的水玻璃溶液及水泥浆溶液的混合液注入渗漏通道中,水玻璃与水泥浆的混合液快速凝结、迅速封住渗漏通道,起到隔水的作用.其施工步骤为成孔→找渗漏通道→双液注浆→巩固.文章还列举了天津地区采用双液注浆法处理基坑渗漏的两则案例.     

森林沼泽景观区有机质 对元素表生地球化学特征的影响机制

有机质干扰是困扰森林沼泽景观区化探工作多年的问题。对有机质对元素表生地球化学特征的影响机制进行了初步研究,结果表明:有机质主要通过直接吸附元素和改变环境的物理化学条件这两种方式对元素表生地球化学特征产生影响,两者之间又存在着密切的关系。研究结果较好地解释了由于有机质的干扰而使化探异常发生的变化。     

聚氨酯泡塑富集—石墨炉原子吸收分光光度法测定土壤样品中的痕量铊

本文论述了一种聚氨酯泡塑预富集—石墨炉原子吸收分光光度法测定土壤样品中痕量铊的方法。样品经盐酸—硝酸—高氯酸—氢氟酸分解后,再加入10％硝酸。在Fe件和过氧化氢介质中,痕量铊被聚氨酯泡塑富集。用蒸馏水在沸水浴中解脱,以抗坏血酸作基体改进剂消除基体影响后,用石墨炉原子吸收分光光度法测定痕量铊。方法检出限为0．2ng／g。用本方法测定土壤国家一级标准物质中痕量铊,结果与推荐值相符,12次检测结果的精密度（RSD）为：5．05％～8．74％。     

条件非线性最优扰动方法在黑潮目标观测研究中的应用

对近年来利用条件非线性最优扰动（Conditional Nonlinear Optimal Perturbation,CNOP）方法开展的黑潮目标观测研究进行了总结,主要包括日本南部黑潮路径变异的目标观测研究、黑潮延伸体模态转变的目标观测研究和源区黑潮流量变化的目标观测研究。通过计算这些事件的CNOP型扰动,发现这些事件的CNOP型扰动具有局地特征,可以作为实施目标观测的敏感区。理想回报试验结果表明,如果在由CNOP方法识别的敏感区内实施目标观测,则会大幅度提高上述事件的预报技巧。