44 Years Hindcast of the sea level and circulation in the Baltic Sea     

J. Jędrasik  W. Cieślikiewicz  M. Kowalewski  K. Bradtke  A. Jankowski 《Coastal Engineering》2008

The subject of the investigation was the multiyear hindcast of the sea level elevations and currents over the Baltic Sea. The approach follows to the HIPOCAS project conception and contained the 3D hydrodynamic model using boundary conditions from the atmosphere and catchment for 44-year period referring to the second half of the 20th century.  相似文献   

Spatial macrozoobenthic distribution patterns in relation to major environmental factors- A case study from the Pomeranian Bay (southern Baltic Sea)   总被引：2，自引：0，他引：2  

M. Glockzin  M.L. Zettler   《Journal of Sea Research》2008,59(3):144-161

The aim of this study was to identify potential environmental “key factors” causing spatial distributions of macrozoobenthic communities to improve our understanding concerning benthic biotic/abiotic interactions and ecosystem functioning. To this end benthic and environmental data, collected over a period of 4 years (2003–2006) at 191 sampling stations in the Pomeranian Bay (southwest Baltic Sea), were analysed. This represents the most comprehensive study performed in this respect in the Baltic Sea up to date and also the necessary first step towards a model able to predict macrofaunal distributions regarding autecological species-environment interactions. Based on species abundances, distinctive macrobenthic community patterns were identified and evaluated via univariate correlation methods, multivariate numerical classification and ordination techniques (e.g. PCA, CCA). These patterns were caused by clear responses of several benthic species to certain prevailing environmental conditions. The observed distribution of selected species followed a strong gradient of depth and was explained best by the sediment parameters total organic carbon (TOC), median grain size and sorting. By using different statistical methods these abiotic/biotic interactions were modelled allowing to extend our knowledge concerning ecosystem functioning, and provide a tool to assess natural and anthropogenic forced changes in species distribution.  相似文献   

基于三维图像模式识别的西藏东南部地震灾害损失风险评估   总被引：1，自引：0，他引：1       下载免费PDF全文

李昌珑  李宗超  吕红山  高孟潭 《地球物理学报》2019,62(1):393-410

本文在对西藏东南部各县的建筑类型、数量、易损性调查的基础上,对不同类型的建筑建立了模式类向量,使用三维图像模式识别技术估计了各类型建筑在西藏东南部各县市的数量分布,建立了不同建筑物的结构易损性和人口易损性模型,并且估算了西藏东南部各县在遭遇一次设定地震时的损失分布和基于危险性的未来50年可能的损失分布情况.本文研究表明,若曲松—桑日发生7.5级地震,可能造成拉萨、山南两市较重的人员伤亡,其中曲松县和乃东区伤亡最重.西藏东南部未来50年建筑地震风险最高的地区是拉萨市区、林芝市区和错那县,其中拉萨市区的建筑财产损失风险最高.  相似文献   

GMS卫星红外云图强对流云团的识别与追踪   总被引：30，自引：0，他引：30  

白洁  王洪庆  陶祖钰 《热带气象学报》1997,13(2):158-167

利用ＧＭＳ静止气象卫星探测所得到的红外云图资料，用计算机图像学技术来研究经对流云图的识别和追踪，以求能够准确，及时地发现并追踪象强对流云团这种能够造成强烈灾害的天气系统。对红我云图的图象处理，提出区域平滑滤波和阈值剔除相结合的强对流云团算法，对于过滤出的经对流云团，应用图象处轮廓编码法的Ｔ算法和ＩＰ算法提取出它的边界，边界初始点。  相似文献   

四川龙门山构造带构造样式浅析     

李娟  李忠权  王平 《云南地质》2012,(2):272-276

总结前人研究成果,综合野外实地地质调查、室内剖面制作,实例验证龙门山构造带构造样式、组合特征,提出有益见解。  相似文献   

Discovering relative motion patterns in groups of moving point objects     

Patrick Laube Corresponding author  Stephan Imfeld  Robert Weibel 《International journal of geographical information science》2013,27(6):639-668

Technological advances in position‐aware devices are leading to a wealth of data documenting motion. The integration of spatio‐temporal data‐mining techniques in GIScience is an important research field to overcome the limitations of static Geographic Information Systems with respect to the emerging volumes of data describing dynamics. This paper presents a generic geographic knowledge discovery approach for exploring the motion of moving point objects, the prime modelling construct to represent GPS tracked animals, people, or vehicles. The approach is based on the concept of geospatial lifelines and presents a formalism for describing different types of lifeline patterns that are generalizable for many application domains. Such lifeline patterns allow the identification and quantification of remarkable individual motion behaviour, events of distinct group motion behaviour, so as to relate the motion of individuals to groups. An application prototype featuring novel data‐mining algorithms has been implemented and tested with two case studies: tracked soccer players and data points representing political entities moving in an abstract ideological space. In both case studies, a set of non‐trivial and meaningful motion patterns could be identified, for instance highlighting the characteristic ‘offside trap’ behaviour in the first case and identifying trendsetting districts anticipating a political transformation in the latter case.  相似文献   

Comparative tempo‐spatial pattern analysis: CTSPA     

Y. Xie  X. Ye 《International journal of geographical information science》2013,27(1):49-69

A new method is illustrated for describing the characteristics of urban pattern changes over different time periods. This method employs vector geometry, paired centroids, shared boundary lines, and overlain polygons. Three new statistics are proposed for characterizing local polygon feature changes in quantity, shape, and size. These statistics are standardized, based on conventional theories from urban geography such as directional concentric zones and user‐designated corridors to document both regional and global patterns of land‐use change. This method is used to analyse land‐use changes in metropolitan Detroit between 1990 and 2000. The Detroit case study indicates that the CTSPA statistics are effective in describing urban spatial pattern changes and in characterizing the evolution of discrete urban landscapes over selected periods.  相似文献   

LAMOST观测控制系统体系结构设计   总被引：1，自引：0，他引：1  

王坚  金革  黄鲲  李峰  任间  虞孝麒 《天文研究与技术》2005,2(2):114-121

由于大天区面积多目标光纤光谱天文望远镜(LAMOST)系统非常复杂,系统研制的时间比较长,系统建成后有相当长的使用年限,就要求观测控制系统(OCS)有足够长的生命周期(使用、维护及升级),可扩展性和良好的可维护性,因此系统需要一个合理健全、内在一致的体系结构。根据OCS的建模和体系结构的概念,在对OCS建模及参考各种体系结构模式的基础上完成了基于构件的层状的OCS系统体系构架,融合了MVC,代理等体系结构模式。详细讨论了OCS体系结构的静态模型和动态模型,并在OCS的1级系统实现了此体系结构。  相似文献   

半变异函数球状模型2次套合结构优化算法   总被引：1，自引：0，他引：1  

舒彦军  张立亭 《地理空间信息》2012,(2):61-63

为了精确描述适用于区域化变量理论的自然现象的空间随机性和结构性,运用遗传算法和模式搜索法对半变异函数球状模型2次套合结构进行了优化,得到了较好的拟合精度。  相似文献   

两种短期降水集合预报方案的对比试验   总被引：2，自引：1，他引：1  

胡宗全  韦浩宁  顾红芳 《气象与减灾研究》2008,31(1):23-28

将MM5V3作为试验模式,利用初值扰动和物理参数化方案,分别对东南沿海地区2004年7—9月的短期降水进行了模拟,并运用均方根误差法对模拟试验效果进行了评估检验,以比较两种方案的集合预报效果。结果表明,对于汛期短期降水预报而言,两种方案的预报效果都有一定的改进。相对于初值误差而言,积云对流过程在汛期降水过程中起着更为重要的作用,因而物理参数化方案扰动的集合预报效果,总体优于基于初值扰动的集合预报效果。研究还发现,模式物理参数化方案扰动的集合预报效果在9月出现了明显的下滑,这主要由于7—8月对流活动旺盛,而9月对流活动随热力因素减弱而减弱的原因所致。  相似文献