结合卫星像影分析水库地震的形成原因     

孔凡健 《华南地震》1992,(2)

本文应用卫星影像分析了我国几个水库诱发地震震例,提出了库区内应力叠加模式,对水库地震的成因,做了探讨。  相似文献   

A hyperspectral experiment over tropical forests based on the EO-1 orbit change and PROSAIL simulation     

Lênio Soares Galvão  Alana Almeida de Souza  Fábio Marcelo Breunig 《地理信息系统科学与遥感》2020,57(1):74-90

ABSTRACT

We designed a unique hyperspectral experiment from the Earth Observing One (EO-1) orbit change to evaluate solar illumination effects over tropical forests in Brazil. Ten nadir-viewing Hyperion images collected over a fixed site and period of the year (July to August) were selected for analysis. We evaluated variations in reflectance and in 16 narrowband vegetation indices (VIs) with increasing solar zenith angle (SZA) from the pre-drift (2004–2008) to the EO-1 drift period (2011–2016). To detect changes in reflectance and shadows, we applied spectral mixture analysis (SMA) and principal component analysis (PCA) and calculated the similarity spectral angle (θ) between the vegetation spectra measured with variable SZA. The magnitude of the illumination effects was also evaluated from change-point analysis and nonparametric Mann-Whitney U tests applied over the time series. Finally, we complemented our experiment using the PROSAIL model to simulate the VIs variation with increasing SZA resultant from satellite drift. The results showed significant changes in Hyperion reflectance and VIs, especially when the EO-1 crossed the study area at earlier times and larger SZA in 2015 (9:05 a.m.; SZA = 59°) and 2016 (8:30 a.m.; SZA = 67°). Compared to the pre-drift period (10:30 a.m.; SZA = 45°), the SZA differences of 14° (2015) and 22° (2016) increased the shade fractions and decreased the vegetation brightness. PCA separated the pre-drift and drift reflectance datasets, showing shifts in scores due to changes in brightness. θ increased with SZA, indicating changes in the shape of the vegetation spectra with drift. For most VIs, the change-point analysis indicated 2015 (SZA = 59°) as the predominant year of detected changes. Compared to the EO-1 original orbit, the Plant Senescence Reflectance Index (PSRI), Anthocyanin Reflectance Index (ARI) and Structure Insensitive Pigment Index (SIPI) presented the largest positive changes during drift, while the Photochemical Reflectance Index (PRI), Visible Atmospherically Resistant Index (VARI) and Enhanced Vegetation Index (EVI) had the largest negative changes. The effect size of the illumination geometry on these VIs was large, as indicated by increasing values of the Cohen’s r metric toward 2016. The anisotropy of the Hyperion VIs was generally consistent with that from PROSAIL in the simulated pre-drift and drift periods. Focusing on structural indices, it affected the relationships between VIs and simulated leaf area index (LAI) at large SZA.  相似文献   

The impact of seasonality on multi-scale feature extraction techniques     

Brian Moore  Jacob J. McKee 《International Journal of Digital Earth》2020,13(1):9-21

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Extensions of linear discriminant analysis for statistical classification of remotely sensed satellite imagery     

Paul Switzer 《Mathematical Geology》1980,12(4):367-376

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An evaluation of the role played by remote sensing technology following the World Trade Center attack     

Charles?K.?HuyckEmail author  Beverley?J.?Adams  David?I.?Kehrlein 《地震工程与工程振动(英文版)》2003,2(1):159-168

Remote sensing technology has been widely recognized for contributing to emergency response efforts after the World Trade Center attack on September 11th, 2001. The need to coordinate activities in the midst of a dense, yet relatively small area, made the combination of imagery and mapped data strategically useful. This paper reviews the role played by aerial photography, satellite imagery, and LIDAR data at Ground Zero. It examines how emergency managers utilized these datasets, and identifies significant problems that were encountered. It goes on to explore additional ways in which imagery could have been used, while presenting recommendations for more effective use in future disasters and Homeland Security applications. To plan adequately for future events, it was important to capture knowledge from individuals who responded to the World Trade Center attack. In recognition, interviews with key emergency management and geographic information system (GIS) personnel provide the basis of this paper. Successful techniques should not be forgotten, or serious problems dismissed. Although widely used after September 11th, it is important to recognize that with better planning, remote sensing and GIS could have played an even greater role. Together with a data acquisition timeline, an expanded discussion of these issues is available in the MCEER/NSF report “Emergency Response in the Wake of the World Trade Center Attack; The Remote Sensing Perspective” (Huyck and Adams, 2002)  相似文献   

高光谱图像数据变换编码压缩方法   总被引：6，自引：1，他引：5  

王春胜  禹秉熙  戴逸松  文大化 《遥感学报》2000,4(2):95-99

三维ＤＣＴ变换编码包括谱段方向的一维ＤＣＴ变换和由此产生的特征值图像的二维ＤＣＴ变换编码。谱段方向一维ＤＣＴ变换的主要作用是去除光谱方向的数据相关性,并产生由ＤＣＴ系数构成的并与各个谱段相对应的特征值图像。特征值图像的压缩由ＪＰＥＧ算法完成,图像的压缩比由ＪＰＥＧ的量化因子ｑ控制。图像边缘特征对高光谱图像的应用具有非常重要的意义,在高光谱图像的压缩过程中要尽量保持图像的边缘特征。我们设计了具有图像  相似文献   

多项式的井间地震速度场反演方法     

乐友喜  曾有良 《物探与化探》2006,30(2):169-171,174

基于契比雪夫多项式的旅行时反演方法,不需进行入射角扫描,首先用多项式表示出深度和慢度,计算出从源点到接收点的旅行时间,通过与实际时间的误差修改模型参数,经过反复迭代,最终得到地下复杂构造的界面形态和速度变化。与网格化速度反演方法相比,计算的未知数少,对初始地质模型的依赖性小。模型试算表明,在初始地质模型与实际地质模型差别较大时,仍能取得比较好的反演结果。  相似文献   

长春市南湖叶绿素a浓度高光谱估测模型研究   总被引：9，自引：0，他引：9       下载免费PDF全文

段洪涛  张柏  宋开山  王宗明  胥彦玲 《水科学进展》2006,17(3):323-329

利用野外高光谱仪(ASD Field Spec radiometer)在长春南湖进行了反射光谱测量和同步水质采样分析,通过研究水体藻类叶绿素a浓度与其高光谱反射特征之间的相关关系,采用单波段反射率、反射率比值法和一阶微分法分别建立了叶绿素a的高光谱定量模型。结果表明:三者与叶绿素a线性相关程度都比较高,决定系数在0.70左右,而且其显著水平P<0.01,都可以用于叶绿素a的定量遥感,其中单波段模型效果最好。为今后利用高光谱传感器在南湖进行叶绿素a浓度大面积遥感反演提供了研究基础。  相似文献   

基于高光谱遥感反射比的太湖水体叶绿素a含量估算模型   总被引：19，自引：1，他引：19  

焦红波  查勇  李云梅  黄家柱  韦玉春 《遥感学报》2006,10(2):242-248

旨在寻找叶绿素a的高光谱遥感敏感波段并建立其定量估算模型。通过对太湖水体的连续监测，获得了从2004年6月到8月3个月的太湖水体高光谱数据和水质化学分析数据。利用实测的高光谱数据分析计算太湖水体的离水辐亮度和遥感反射比；然后，通过相关分析寻找反演叶绿素a浓度的高光谱敏感波段，进而建立反演太湖水体叶绿素a浓度的高光谱遥感定量估算模型，并用相关数据对模型进行精度分析。研究发现，水体的遥感反射比光谱在719nm和725nm存在两个峰，其中719nm处的峰更明显且稳定。通过模型的对比分析，发现用这两个峰值处的遥感反射比参与建模可以提高叶绿素a的估算精度；并且认为由反射比比值变量R719／R670所建立的线性模型对叶绿素a浓度的估算精度最理想。  相似文献   

混合光谱分解模型提取水体叶绿素含量的研究     

肖青  闻建光  柳钦火  周艺 《遥感学报》2006,10(4):559-567

遥感监测水体叶绿素含量是水质遥感研究的难点之一。本文通过研究不同叶绿素含量水体反射率的光谱特征，确定了提取叶绿素a含量的最佳特征波段，建立了太湖水体叶绿素a的混合光谱模型。研究发现，混合光谱模型提取的水体叶绿素a百分比浓度与同步采样分析的叶绿素a浓度之间有较好的线性相关性。并基于TM和HEPERION图像利用此模型生成了叶绿索a浓度分布图。研究结果表明，混合光谱分解模型可以作为遥感监测水体叶绿素a含量的定量模型。  相似文献