Physical criterion to evaluate seismic activity associated with the seismic cycle of great interplate earthquakes     

Takane Hori  Yoshiyuki Kaneda 《Journal of Seismology》2004,8(2):225-233

A new criterion is introduced to judge if the vicinity of the source region of a great interplate earthquake is in an active period. It is based on the stress change caused by the great earthquake. A region is regarded as being in an active period of seismicity if the occurrence rate of earthquakes on faults in the stress shadow of the great earthquake is significantly higher than in the early stage of the seismic cycle, and if the stressing rate of these faults is sufficiently low. This criterion was applied to the seismicity in the central part of southwest Japan before and after the 1944 Tonankai and 1946 Nankai earthquakes. The results show that before the 1944 Tonankai earthquake, the region was in an active period from at least 1927.The region was in a quiet period for almost50 years after the 1946 Nankai earthquake.Data after 1995 show that the region is once more in an active period of seismicity preceding the next great interplate earthquakes along the Nankai trough,although the total number of earthquakes has not yet significantly increased. Our results indicate that earthquake probability in the central part of southwest Japan will become high in the coming decades until the next great interplate earthquakes along the Nankai trough.  相似文献   

EVACUATION BEHAVIOR IN RESPONSE TO NUCLEAR POWER PLANT ACCIDENTS*     

Donald J. Zeigler  James H. Johnson 《The Professional geographer》1984,36(2):207-215

A telephone survey of 2,595 households on Long Island, NY provides a data base for analyzing potential spatial behaviors in response to an accident at the Shoreham Nuclear Power Station in Suffolk County. These intended behaviors approximated the actual behaviors of Three Mile Island area residents during the general emergency at that plant in 1979. Using evacuations from natural and other technological hazards as a basis for comparison, we conclude that evacuations in response to nuclear power plant accidents are likely to be characterized by an extreme over-response to limited protective action advisories; this phenomenon needs to be considered in behaviorally-based radiological emergency response planning.  相似文献   

多重约束下的建筑物阴影提取   总被引：6，自引：0，他引：6  

郭海涛  徐青  张保明 《武汉大学学报(信息科学版)》2005,30(12):1059-1062

在基于结构线一侧灰度统计法进行阴影检测的基础上,结合了灰度约束、几何约束、上下文约束和其他辅助信息,提出了一种多重约束下的建筑物阴影提取方法,实现了对建筑物阴影的提取,并利用IKONOS影像和航空像片进行了试验,证明该算法是有效而稳健的。  相似文献   

Topography-adjusted solar radiation indices and their importance in hydrology     

Nikos Mamassis  Andreas Efstratiadis  Ilektra-Georgia Apostolidou 《水文科学杂志》2013,58(4):756-775

Abstract

Solar radiation, direct and diffuse, is affected by surface characteristics, such as slope, aspect, altitude and shading. The paper examines the effects of topography on radiation, at multiple spatiotemporal scales, using suitable geometric methods for the direct and diffuse components. Two indices are introduced for comparing the direct radiation received by areas at the same and different latitudes. To investigate the profile of direct radiation across the whole of Greece, these are evaluated from an hourly to annual basis, via GIS techniques. Moreover, different approaches are examined for estimating the actual global radiation at operational spatial scales (sub-basin and terrain), according to the available meteorological data. The study indicates that the errors of typical hydrometeorological modelling formulas, which ignore the topographic effects and the seasonal allocation of direct and diffuse radiation, depend on the spatial scale and are non-uniformly distributed in time. In all cases, the estimations are improved by applying the proposed adjustment approaches. In particular, the adjustment of the measured global radiation ensures up to 10% increase of efficiency, while the modified Angström formula achieves slight (i.e. 2–4%) increase of efficiency and notable reduction of bias.

Editor Z.W. Kundzewicz

Citation Mamassis, N., Efstratiadis, A. and Apostolidou, I.-G., 2012. Topography-adjusted solar radiation indices and their importance in hydrology. Hydrological Sciences Journal, 57 (4), 756–775.  相似文献   

亚米级遥感影像的建筑物高度反演方法及其验证北大核心CSCD     

刘晓忠  冯存均  邓小渊  詹远增  于辉  王兴坤 《测绘通报》2022,(8):128-132

建筑物高度是现代化都市监测、规划、管理及各城市经济活动中的基础性数据,为实现建筑物高度信息的提取,本文提出了一种基于玻尔兹曼曲线的建筑物高度反演方法。首先,利用建筑物影像的光谱特性,采用多尺度分割和遥感指数分类的办法获取建筑物阴影感兴趣区域,根据玻尔兹曼曲线函数拟合获取阴影的亚像素位置,线性拟合得到阴影边界;然后,根据太阳、卫星、建筑物和其阴影的几何关系,构建高度反演模型,估算建筑物高度;最后,选择宁海为研究区,选取在轨的主流亚米级高分二号、高景一号、北京二号、WorldView-2卫星遥感数据进行精度验证。试验结果表明,计算的建筑物高度中误差优于2.5 m,可用于一般的城市卫星遥感监测。  相似文献   

改进的航摄影像Mask匀光算法   总被引：1，自引：1，他引：0  

袁修孝  韩宇韬  方毅 《遥感学报》2014,18(3):630-641

针对航摄影像中存在高亮区域和大面积阴影等灰度剧烈变化区对匀光影像造成的灰度失真现象,本文对Mask匀光算法中的背景影像生成方法进行了改进,通过使用扩张吞噬算法明显改善了背景影像的质量。经对带有高亮度屋顶、高亮度水体和大面积阴影等特殊区域的航摄影像匀光实验表明,本文方法较现行Mask匀光方法具有更好的匀光效果,不但有效消除了特殊区域交界处影像的灰度失真现象,而且明显增强了暗区影像的纹理清晰度。  相似文献   

仪表着陆系统下滑道受遮蔽影响的快速计算     

闫朴 《全球定位系统》2014,(5):70-74

作为飞机进近阶段最依赖的导航设备,仪表着陆系统对电磁环境的变化非常敏感。针对机场运行中最常见的场地保护区入侵问题和违规修建建筑物等情况,提出了下滑道受遮蔽物影响的快速计算方法。结合天线镜像理论和下滑信号空间合成原理,编写了仿真程序。对比实验表明,该快速计算方法能够实现定性分析,可以为机场管理机构和空中交通管理部门提供决策依据。  相似文献   

利用边界链编码和HMM进行SAR图像阴影建模和分类   总被引：1，自引：0，他引：1  

杨露菁  王德石  李煜 《武汉大学学报(信息科学版)》2010,(2)

针对利用合成孔径雷达图像中的阴影信息进行目标识别的问题,提出了一种边界链编码和隐马尔可夫模型(HMM)相结合的合成孔径雷达图像目标识别方法。该方法利用链编码技术来描述SAR图像阴影边界的形状,可以很好地反映形状的特性,且计算上很有效;利用HMM统计建模方法对阴影边界的链编码进行建模和分类,从而实现SAR图像的自动目标识别。使用MSTAR数据库中的SAR图像数据对该方法进行了验证和分析,分类结果证明只利用阴影信息进行分类的可行性,且该方法可以有效地实现SAR图像的目标识别。  相似文献   

基于RS/GIS的城市植被生态价值分析与评价     

王维磊  郭连杰  尚冉冉  吕秀美 《地理空间信息》2019,17(7):78-81,I0002

根据济南市历下区TM遥感影像获取了历下区植被归一化指数(NDVI),利用单窗算法提取了地表温度;通过对比NDVI分布与温度分布分析了植被对城市热岛效应的缓解作用。采用改进的CASA模型提取了植被第一性净生产力(NPP),进而获得了植被的固碳释氧能力,分析了城市植被的固碳释氧价值。采用影子替代法对植被生态价值进行定量化,从而可对济南市历下区植被分布进行科学规划,以提高城市整体的人居适宜性。结果显示,城市植被生态价值非常可观,热岛缓解价值最大可达249021元/hm^2,植被固碳和释氧价值最大分别为15818.2元/hm^2和18645.2元/hm^2。  相似文献