区域旅游发展中的行政冲突及调控机制——以张家界为例

在问卷调查与实地访谈的基础上,通过定性与定量相结合的分析方法,剖析张家界因旅游开发而单独立市以来在旅游产业和城市经济发展中所取得的成就,同时也揭示了张家界市各县级行政区之间旅游产业分化发展,功能性、结构性重复建设,企业之间恶性削价竞争以及相互打压市场形象等问题与矛盾.据此提出市域旅游经济空间矛盾调控的切入点,主要包括:...     

高光谱遥感数据三次光滑样条滤噪

分析了高光谱遥感数据噪声滤波的作用和现状，实现了一种基于三次光滑样条函数的高光谱遥感数据噪声滤波算法，解决了目前高光谱遥感数据噪声滤波算法自适应效果不理想的问题。通过对AVIRIS数据试验，证明此方法简单易行，计算精度高，具有良好的局部自适应拟合能力，并能有效地滤除数据中的噪声，改善数据质量。     

A geospatial framework to estimate depth of scour under buildings due to storm surge in coastal areas

Hurricanes and tropical storms represent one of the major hazards in coastal communities. Storm surge generated by strong winds and low pressure from these systems have the potential to bring extensive flooding in coastal areas. In many cases, the damage caused by the storm surge may exceed the damage from the wind resulting in the total collapse of buildings. Therefore, in coastal areas, one of the sources for major structural damage could be due to scour, where the soil below the building that serves as the foundation is swept away by the movement of the water. The existing methodologies to forecast hurricane flood damage do not differentiate between the different damage mechanisms (e.g., inundation vs. scour). Currently, there are no tools available that predominantly focus on forecasting scour-related damage for buildings. Such a tool could provide significant advantages for planning and/or preparing emergency responses. Therefore, the focus of this study was to develop a methodology to predict possible scour depth due to hurricane storm surges using an automated ArcGIS tool that incorporates the expected hurricane conditions (flow depth, velocity, and flood duration), site-specific building information, and the associated soil types for the foundation. A case study from Monmouth County (NJ), where the scour damages from 2012 Hurricane Sandy were recorded after the storm, was used to evaluate the accuracy of the developed forecasting tool and to relate the scour depth to potential scour damage. The results indicate that the developed tool provides relatively consistent results with the field observations.     

Hazardous processes and events from glacier and permafrost areas: lessons from the Chilean and Argentinean Andes

Glacier and permafrost hazards such as glacial‐lake outburst floods and rock–ice avalanches cause significant socio‐economic damages worldwide, and these processes may increase in frequency and magnitude if the atmospheric temperature rises. In the extratropical Andes nearly 200 human deaths were linked to these processes during the twentieth century. We analysed bibliographical sources and satellite images to document the glacier and permafrost dynamics that have caused socio‐economic damages in this region in historic time (including glacial lake outburst floods, ice and rock–ice avalanches and lahars) to unravel their causes and geomorphological impacts. In the extratropical Andes, at least 15 ice‐dammed lakes and 16 moraine‐dammed lakes have failed since the eighteenth century, causing dozens of floods. Some floods rank amongst the largest events ever recorded (5000 × 10⁶ m³ and 229 × 10⁶ m³, respectively). Outburst flood frequency has increased in the last three decades, partially as a consequence of long‐term (decades to centuries) climatic changes, glaciers shrinkage, and lake growth. Short‐term (days to weeks) meteorological conditions (i.e. intense and/or prolonged rainfall and high temperature that increased meltwater production) have also triggered outburst floods and mass movements. Enormous mass failures of glaciers and permafrost (> 10 × 10⁶ m³) have impacted lakes, glaciers, and snow‐covered valleys, initiating chain reactions that have ultimately resulted in lake tsunamis and far‐reaching (> 50 km) flows. The eruption of ice‐covered volcanoes has also caused dozens of damaging lahars with volumes up to 45 × 10⁶ m³. Despite the importance of these events, basic information about their occurrence (e.g. date, causes, and geomorphological impact), which is well established in other mountain ranges, is absent in the extratropical Andes. A better knowledge of the processes involved can help to forecast and mitigate these events. Copyright © 2014 John Wiley & Sons, Ltd.     

A Parametric Approach for Dealing with Compositional Rounded Zeros

In this work, a parametric approach for replacing data below the detection limit, also known as rounded zeros, in compositional data sets is proposed. Compositional rounded zeros correspond to small proportions of some whole that cannot be reliably detected by the analytical instruments under given operating conditions. This kind of zeros appear frequently in the data collection process in geosciences. They must be treated in an adequate way before some multivariate analysis can be applied. Our procedure results from a modification of the Expectation-Maximization (EM) algorithm and is based on the additive log-ratio transformation. Its coherence with the nature of compositional data and with basic operations in the simplex sample space is checked. Using real data sets, we find that this approach improves other parametric and non-parametric techniques for compositional rounded zeros.     

基于光谱特征的湿地湿生植物信息提取研究

基于湿生植物光谱特征分析,采用面向对象分类方法提取湿地典型植被信息。在大量的野外实地调查基础上,确定提取的典型植物类型为芦苇(Phragmites australis)、长芒稗(Echinochloa crusgallii)和睡莲(Nymphaeatetragona);采集湿地优势植物光谱数据,将优势植物与提取对象芦苇、长芒稗和睡莲的光谱特征进行相关性分析,获取物种间区分性好的波段及波段组合,参与影像分割权重的设置;根据典型植被的分布特征,确定面向对象分割尺度(其中芦苇的分割尺度为50,长芒稗的分割尺度为20,睡莲的分割尺度为100)。通过研究发现:基于光谱特征分析的面向对象的分类精度为96%,而未利用光谱特征的面向对象的分类精度为87.3%,传统监督分类精度仅为82.3%。证明在面向对象提取前对植物光谱特征分析得到区分性好的波段及波段组合参与分割,对提高分类精度起关键作用。     

基于实测与模拟的青海湖冰厚时空变化特征

湖冰厚度是湖泊在封冻期的重要物理参数,明晰其时空变化特征对于认识气候变暖背景下的湖冰响应规律具有重要的理论价值和现实意义.基于ERA5 Climate Reanalysis气温数据集、MODIS MOD09GQ数据产品和2019年湖冰钻孔测厚数据及雷达测厚数据,重建20002019年青海湖冰厚时间序列并分析其时空变化特...     

Modeling the seismic response of basin-edge structure by a sequential waveform method

A sequential waveform method is developed to simulate the seismic response of basin-edge structure excited by a plane incident P-wave. The full procedure involves: (a) a previous parameterization of the investigated model using the seismic wave velocities and depths of the sedimentary stratifications; (b) an input motion determined from the records at stations installed on hard rock; (c) forward computation of the P-SV elastic wave field by means of a two-dimensional finite difference (FD) method; (d) the optimization of the model vector using simulated annealing technique and comparing the simulated seismic response of the tested structure with the observed wave field; (e) the correction of the initial model by trial-and-error by testing the differences between synthetics and observed data, and (f) the final solution obtained by iteration using the conjugate gradient algorithm. The search of an optimal basin-edge model has been parallel processed by varying the shapes and velocities of strata on the basis of the fitting of relative timing, amplitude and phase between the output and the observed data. The input motion and sensitivity have been checked and the validity of the method has been demonstrated by numeric analysis. Using the teleseismic records generated by 7 earthquakes recorded at 26 broadband seismic stations, we have studied the seismic velocity structure of the southern edge of the Jiyang depression located in the Bohai Bay basin, northern China. Two cross sections show an agreement between the velocity results and the geological sections available in the region. In addition, we obtain evidence of three hidden faults under the sections and features that suggest major extensions at the Paleogene.     

联合Delaunay三角网的等高线群综合研究

采用联合Delaunay三角网来提取成组等高线的弯曲,在弯曲处利用平三角形连接法进行局部地形结构线的连接,并建立起地形结构线的树状结构。运用方根模型确定谷地选取的数量指标,并提出了一种新的数学模型以确定谷地选取的质量指标,完成等高线群的自动综合。研究和实验表明,该方法充分顾及了地貌形态特征,谷地选取合理,概括程度适当,并完全避免了相邻等高线相交,综合效果较好。     

冲绳海槽北部稀土元素沉积地球化学研究

本文对冲绳海槽北部海底表层沉积物和４个柱将苦芯沉积物样品的稀土元素沉积地球化学特征进行了系统的分析。研究结果表明：调查区表层沉积物ＲＥＥ的分布主要与沉积物的物质组成有关，特别是海洋生物沉积物组份的比例不仅影响ＲＥＥ总量的分布，而且影响标准化ＲＥＥ分布模式的形态。