A diagnostic study of spectral multiscaling on spatio-temporal accumulations of rainfall fields based on radar measurements over Iowa     

《Advances in water resources》2014

  相似文献   

Study on the Characteristics of Seismic Activity in the Interior of the Ordos Block     

Xu Weijin  Gao Mengtan  Ren Xuemei    Feng Xijie 《中国地震研究》2009,23(4):467-479

The temporal and spatial distribution characteristics of earthquakes in the Ordos block are studied by using historical earthquake data,instrument data of the regional seismic network around the Ordos block and the historical felt earthquake data,and the relationship between seismicity in the Ordos block and seismicity around the Ordos block is discussed. The result shows that the Ordos block is a typical moderate-strong earthquake active region where many M_S≥5.0 destructive earthquakes have occurred. The temporal and spatial distribution of earthquakes in the Ordos block is asymmetrical. The temporal distribution of earthquakes shows a periodic characteristic and the activity of earthquakes in the southeastern Ordos block is higher than in the northwest Ordos block. The M_S≥5.0 moderate size earthquakes in the Ordos block are controlled by the M_S≥6.0 earthquake around the Ordos block.  相似文献   

基于GeoDatabase模型的长江河口时空数据建模研究   总被引：1，自引：0，他引：1  

蔡中祥  沈焕庭  熊伟 《海洋技术学报》2005,24(3):1-4

传统的数据模型或数据存储方式已经影响了长江河口的研究进展,对时空数据的组织建模研究,将有利于长江河口研究更好地面向动态过程.论文从时空数据模型的角度,分析和总结了长江河口研究数据的特点、内容,使用简单的方法构建了长江河口时空数据模型,并探讨了时空数据模型的实际应用.  相似文献   

未来气候变化背景下我国橡胶树寒害事件的变化特征     

李宁  白蕤  李玮  张蕾  易克贤  陈淼  陈歆 《气候变化研究进展》2018,14(4):402-410

利用1981—2010年历史气象数据和2031—2060年（RCP2.6和RCP8.5）气候情景数据,根据橡胶寒害等级指标,结合插值分析、提取分析和地图代数等空间分析方法,研究在未来气候情景下我国橡胶树寒害事件的变化特征。结果表明：(1) RCP2.6和RCP8.5气候情景下2031—2060年我国橡胶种植适宜区基本呈现寒害发生降低的趋势,其中次适宜区（III）和局部可植区（IV）的降低幅度较为明显,有向高一等级适宜区转化的趋势。(2)我国橡胶树寒害中心的纬度,由1981—2010年的22.5°~23.5°N向北移动至2031—2060年RCP2.6情景下的24.0°~24.5°N和RCP8.5情景下的23.5°~24.0°N。(3) 2种气候情景下,2031—2060年我国海南、广西、广东、福建等植胶区橡胶树寒害发生概率（较基准时段1981—2010年）主要呈现降低趋势,云南植胶区在2种气候情景下有明显的差异,表现为RCP2.6情景下,轻度和特重寒害呈现降低趋势,中度和重度寒害呈现增加趋势;RCP8.5情景下,轻度和重度寒害呈现降低趋势,中度和特重寒害呈现增加趋势。(4)对比2种气候情景较基准时段的变化情况,RCP2.6情景对橡胶树轻度和特重寒害影响较大,RCP8.5情景对橡胶树中度和重度寒害影响较大。  相似文献   

Spatio-temporal analysis of crime by developing a method to detect critical distances for the Knox test   总被引：1，自引：0，他引：1  

Mohsen Kalantari  Bamshad Yaghmaei  Somaye Ghezelbash 《International journal of geographical information science》2016,30(11):2302-2320

The present study examined and compared spatio–temporal interaction of the theft of car parts, shop burglary and motorcycle theft in the central business district (CBD) of the city of Zanjan in Iran. The Knox test was selected to detect spatio–temporal interaction. This test has been criticized as being subjective because the selection of critical distances is arbitrary; thus, a method is proposed to detect critical distances in the Knox test using the mean distance, natural breaks classification of nearest neighbour (NN) distance and Ripley’s k function. Results show obvious differences between the spatio-temporal clusters of the three sets of crimes. They also indicate that changing the spatial cut-offs within a cluster creates different temporal patterns. Of the three criteria for determining critical distances, NN classification based on natural breaks showed more interactions than the other methods.  相似文献   

Bluetooth tracking of humans in an indoor environment: An application to shopping mall visits     

《Applied geography (Sevenoaks, England)》2017

Intelligence about the spatio-temporal behaviour of individuals is valuable in many settings. Generating tracking data is a necessity for this analysis and requires an appropriate methodology. In this study, the applicability of Bluetooth tracking in an indoor setting is investigated. A wide variety of applications can benefit from indoor Bluetooth tracking. This paper examines the value of the method in a marketing application. A Belgian shopping mall served as a real-life test setting for the methodology. A total of 56 Bluetooth scanners registered 18.943 unique MAC addresses during a 19-day period. The results indicate that Bluetooth tracking is a sound approach for capturing tracking data, which can be used to map and analyse the spatio-temporal behaviour of individuals. The methodology also provides a more efficient and more accurate way of obtaining a variety of relevant metrics in the field of consumer behaviour research. Bluetooth tracking can be implemented as a new and cost effective practice for marketing research, that provides fast and accurate results and insights. We conclude that Bluetooth tracking is a viable approach, but that certain technological and practical aspects need to be considered when applying Bluetooth tracking in new cases.  相似文献   

Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids of superficial sediments from three contrasted areas     

Antoine Grémare  Dimitri Gutiérrez  Jean Michel Amouroux  Gilles Vétion 《Progress in Oceanography》2005,65(1):89-111

Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids (THAA and EHHA) and EHAA/THAA ratios of superficial sediments were assessed during 1997-1999 in three areas (i.e., the Gulf of Lions, the Bay of Biscay, and Central Chile) differing in their primary productivity. In all three areas, and even off Central Chile where a strong El Niño event took place during 1997-1998, spatial changes were always much greater than temporal ones. The factors affecting the spatial distributions of amino acid concentrations differed among areas. In the Gulf of Lions, sediment granulometry was apparently the most important driving force of THAA, EHAA, and EHAA/THAA, and there was no marked difference between stations located on the open slope and those in submarine canyons. Conversely, in the Bay of Biscay, there were clear differences between the stations located off Cap-Breton, on the open slope, and those in the Cap-Ferret canyon; the latter two featuring lower EHAA and THAA but higher EHAA/THAA. This pattern is likely to result from the predominance of different sources of organic matter and especially from the importance of continental inputs to the Cap-Breton canyon. Off Central Chile, amino acid concentrations and ratios were both maximal around 100 m depth, probably reflecting the interaction between the primary productivity gradient and the presence of an oxygen minimum zone (OMZ) reducing the degradation of sedimentary organics. When comparing the average values collected in the three areas studied, THAA and EHAA were highest in Central Chile, intermediate in the Bay of Biscay and lowest in the Gulf of Lions. EHAA/THAA ratios were also highest in Central Chile but were lowest in the Bay of Biscay. Differences between the Gulf of Lions and the Bay of Biscay could have been affected by sampling design. In Central Chile, the use of labile organic carbon to total organic carbon (C-LOM/TOC) and EHAA/THAA as indices of organic matter lability led to very similar results. This was not the case in the Bay of Biscay. It is therefore argued that the use of C-LOM/TOC should be restricted to highly productive areas.  相似文献   

The spatial and temporal distribution of pipe formation,offshore Namibia     

J.L. Moss  J. Cartwright 《Marine and Petroleum Geology》2010

A group of nearly 400 pipe structures from the continental slope of northern Namibia are analysed for their spatial and temporal distribution. The pipes most likely formed as a result of highly focused fluid venting, and understanding the factors controlling their distribution in space and time is key to their genesis. We analysed their spatio-temporal distribution using an arbitrary chronostratigraphic timescale, from which it is concluded that the pipes did not form at the same time. Pipe formation is shown to be intermittent and persistent, with 2–29 pipes forming in each of the >20 arbitrary time intervals that are considered to span the Neogene period. The spatial distribution of these pipes is clustered to dispersed. Spatial statistics conducted on the distribution of pipe formation timings have shown that two statistically significant groups of pipes exist within the population, (1) in the North and West and (2) in the South, with the former occurring prior to the latter. Locally, pipe formation is sporadic with clusters and outliers occurring during the same time period. A conceptual model is proposed whereby pipe formation in specific locations is the result of localised breaching of the seals for isolated pressure cells which are locally independent yet broadly controlled. An inferred basinal fluid source is thought to determine the broader patterns of pipe formation, and the focus of this fluid source shifts from North to South with time. At a local scale, multiple local factors interact producing a sporadic pipe formation distribution through a prolonged period of highly focused fluid migration. Once formed, the pipes continued to focus fluids intermittently, leading in some cases to later pockmark formation.  相似文献   

东北亚地区Ms5.0以上地震前后空间电场时空演化特征研究     

杨牧萍  张学民  泽仁志玛  申旭辉  黄建平  钱庚  金艳铭  黄明威 《地震》2021,41(4):78-92

本文利用2005年1月—2009年12月DEMETER电磁卫星观测的极低频/甚低频(ELF/VLF)39 Hz~6 kHz频段电场功率谱密度(PSD)观测量, 将研究频段划分为5个子频段对东北亚地区(38°N~58°N; 105°E~145°E)内发生的8个M_S≥5.0地震前后空间电场时空演化特征进行研究。 研究发现同一地震不同频段异常扰动区域并不完全在同一位置, 且同一地震的不同频段地震前后扰动形态也并不一致; 8个地震40次统计中有25% 的统计数据虽然基本在地震前后所有时间段都超过阈值2σ, 但未见明显扰动规律, 其余75%的统计数据中发现其扰动特征可以归纳为3类: 52%的统计数据在震前扰动幅度增大, 达到最大时发震, 震后持续降低; 7.5%的统计数据在震前扰动幅度达到高值, 而后下降过程中发震; 15%的统计数据在震前扰动幅度一直在增加且绝大部分时间低于2σ, 直至震后超过2σ, 且出现这种类型的异常均为震例的第五频段演化特征。 异常扰动区域主要集中在震中±4°以外的区域。  相似文献   

华北地区库仑应力演化与强震活动关系          下载免费PDF全文

石富强  张辉  邵志刚  徐晶  邵辉成  李玉江 《地球物理学报》1954,63(9):3338-3354

采用更加符合长期变形和震后短期变形的Burgers流变模型,模拟了华北地区1303年以来6.5级以上地震引起的同震和震后库仑应力演化.结合华北地区历史地震期幕活动特征,分析了不同活跃期之间、同一活跃期内不同地震之间的库仑应力加卸载效应.结果表明：华北地区不同活跃期的强震主体活动区受控于历史强震的库仑应力加载作用;每个活跃期内强震活动主体区在空间上的迁移与该活跃期内首个7.5级以上地震的触发作用有关;华北地区每个活跃期内强震活动在时间上表现出的"平静期—活跃警告期—高潮期—剩余释放期"应该是区域动力加载过程的一种表现.岩石圈流变松弛效应引起的库仑应力变化对华北地区强震活动时空演化有显著的促进作用.本研究讨论了库仑应力变化在华北地区历史地震活动时空演化过程中可能扮演的角色,为探索华北地区强震活动空间迁移和韵律特征蕴含的构造动力学过程,以及与之相关的地震危险性判定提供参考依据.  相似文献