基于卫星遥感的临沂市冬小麦种植时空变化特征分析

以临沂地区为研究区,基于Terra/MOD13Q1遥感植被数据产品,通过分析冬小麦的遥感光谱特征、物候历特征及其生物学特性,提取2009—2019年临沂地区冬小麦种植信息,利用GIS空间分析方法和统计分析方法分析了临沂冬小麦种植的时空分布变化规律。结果显示:1)空间上,近10年来临沂地区冬小麦种植面积在2 800～3 000 km~2之间浮动,占整个地区土地面积的17%左右,总体变化较小,种植区域呈南多北少的分布格局,主要集中在兰陵、临沭和郯城; 2)从冬小麦种植稳定度上看,连续种植冬小麦10 a及以上的区域,主要集中在兰陵和郯城,面积为1 638 km~2,稳定度高,连续种植小于4 a的区域有1 914 km~2,主要分布在莒南和费县,种植不稳定; 3)时间上,冬小麦面积由2009年的2 838 km~2增加到2019年的2 985 km~2,变化幅度和年均变化率分别为5.5%和0.5%,呈缓慢增加趋势。本研究为临沂地区冬小麦种植的深入了解以及农业结构调整提供了较为准确、科学的参考依据。     

"4D"数据在生态环境监测与评价中的应用

本文在阐述由DLG、DRG、DEM和DOM组成的4D产品的信息特征的基础上,深入分析了"4D"数据在生态环境监测与评价中的功能,包括生态环境的快速动态监测、三维生态景观的直观分析和表达、DLM与DCM相结合的生态模拟、多时空尺度的生态环境分析与评价等.并以云南省生态环境监测与评价为例,研究了其在生态环境监测与评价中的技术流程,并通过案例分析,生成了系列生态环境地图.     

国内外海洋资料浮标技术现状与发展

海洋资料浮标是长期连续进行海洋监测的主要手段之一。本文简单介绍了国内外海洋资料浮标技术的现状与发展及浮标在我国海洋监测中的应用情况,提出了我国资料浮标技术的研究与发展设想。     

K-means算法复杂度的能量分析方法

传统的算法复杂度分析方法重点对算法的内在流程进行分析,而且对于数据挖掘时具有很大不确定性,执行时间不能准确确定.用物理学原理从能量的角度对数据挖掘中的经典聚类算法K-means进行分析,并从算法的本质上推导出其复杂度下限,推导出该算法能优化到的极限值.     

东营北部凸起带古冲沟储层分布规律研究

在油田勘探与开发中 ,充分认识古冲沟油气藏的勘探与开发是十分重要和有意义的。本文利用东营北部凸起带的地质、钻井、航磁和地震等资料 ,对古冲沟在地震剖面上的特征和古冲沟储层预测方法等进行了研究与探讨     

Is the ocean floor a fractal?

The topographic structure of the ocean bottom is investigated at different scales of resolution to answer the question: Can the seafloor be described as a fractal process? Methods from geostatistics, the theory of regionalized variables, are used to analyze the spatial structure of the ocean floor at different scales of resolution. The key to the analysis is the variogram criterion: Self-similarity of a stochastic process implies self-similarity of its variogram. The criterion is derived and proved here: it also is valid for special cases of self-affinity (in a sense adequate for topography). It has been proposed that seafloor topography can be simulated as a fractal (an object of Hausdorff dimension strictly larger than its topological dimension), having scaling properties (self-similarity or self-affinity). The objective of this study is to compare the implications of these concepts with observations of the seafloor. The analyses are based on SEABEAM bathymetric data from the East Pacific Rise at 13°N/104°W and at 9°N/104°W and use tracks that run both across the ridge crest and along the ridge flank. In the geostatistical evaluation, the data are considered as a stochastic process. The spatial continuity of this process is described by variograms that are calculated for different scales and directions. Applications of the variogram criterion to scale-dependent variogram models yields the following results: Although the seafloor may be a fractal in the sense of the definition involving the Hausdorff dimension, it is not self-similar, nor self-affine (in the given sense). Mathematical models of scale-dependent spatial structures are presented, and their relationship to geologic processes such as ridge evolution, crust formation, and sedimentation is discussed.     

GIS空间数据库的"一库两用"策略研究

GIS有两种普遍的应用需求:空间分析和数字制图,但两种需求对空间数据的要求不完全一致,导致空间数据在同一GIS中无法充分共享。该文探讨能够同时满足两种需求的GIS构建方法。分析地理空间数据存在的冲突,引入"一库两用"思想,建立空间分析型数据模型;利用专家系统机制实现空间分析数据向数字制图数据的转换,转换过程中补充的信息源于专家知识库。该研究有助于解决GIS中数据不一致问题,使GIS更实用、功能更完善。     

城市用地功能精细化识别方法：时序动态图嵌入深度学习模型

多源大数据融合背景下的城市功能区识别是复杂非线性系统的模式识别问题,如何有效地从大规模的轨迹数据中提取出多粒度连续性时变和多尺度空间相互作用的信息是进行城市区域功能识别的关键。本研究设计实现了一种基于时序动态图嵌入的深度学习模型,在融合滴滴出行及兴趣点数据（Point of Interest, POI）基础上,提取城市区域存在的时间和空间上的隐式特征,结合聚类分析实现城市用地功能的语义识别。结果表明,成都市中心的用地功能趋向复合多样化的发展,且用地属性随时间发生作用范围和用地类型的变化,呈现出功能随着城市群体活动而变化的时空规律。与相关文献的对比实验表明,本文提出方法在更细粒度的时间段下进行功能区识别,得到的同一类功能区域内集聚度更高,能够更好的捕获复合型区域在不同时间模式下呈现出的用地功能变化。本研究为城市用地功能识别研究提供了新的技术方法,为城市规划研究人员全面理解城区结构属性提供了有效手段,对推动城市空间得到更合理高效的利用具有一定的价值。     

Modelling and inversion of single-ended refraction data from the shot gathers of multifold deep seismic reflection profiling—an approach for deriving the shallow velocity structure

A multifold crustal-scale deep seismic near-vertical reflection profile generates a large number of single-ended shot gathers, which provide redundant data sets because of overlapping coverage of the shallow refractors. We present an approach for deriving the shallow velocity structure by modelling and inversion of single-ended seismic refraction first arrival traveltime data. We apply this method to a data set acquired with a 12-km long spread with 100 m spacing of shots and receivers, of the Neoproterozoic Marwar basin in the NW Indian shield. The approach is shown to be quite successful for delineating the shallow refractor depths, steep dips and velocities, even in the absence of regular reverse refraction profiles. The study reveals two-layered sedimentary formations, Malani volcanics and a complicated basement configuration of the Marwar basin, and provides a measure of resolution and uncertainty of the estimated model parameters. A seismic section of the near-trace gather is found to be qualitatively consistent with the derived structural features of the basin. The relative highs and lows, observed in the Bouguer gravity profile, further corroborate the derived velocity model. The present approach can be especially useful in offshore areas and elsewhere, where the single-ended multifold seismic profiles are the only available data sets.     

热带西太平洋海域上层海洋热含量的CSEOF分析

基于月平均Argo温、盐度剖面、纬向风和Ni o3.4指数等资料,利用循环平稳经验正交函数(CSEOF)分解法、最大熵谱分析和相关分析等方法,研究了热带西太平洋海域上层(0—700m)海洋热含量的时空变化特征,并探讨了其年际变化的可能原因。结果表明,热带西太平洋海域上层海洋热含量距平场具有显著的东-西向反位相振荡,且这种振荡除了具有较明显的季节变化外,还存在着较强的准2a振荡。此外,热含量距平场还存在着负-正-负的三极式经向模态,该模态除了具有明显的季节变化外,还存在着显著的准4a振荡。进一步分析表明,热含量的准2a振荡与ENSO事件的发生有着非常密切的联系,并对赤道西太平洋纬向风异常有1—2月的滞后响应。