共查询到20条相似文献，搜索用时 515 毫秒
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小波理论及其在地震数据处理中的应用 总被引：9，自引：9，他引：9
小波理论已成为一个新的数学分支，小波分析已成为地球物理、信号处理、图象处理、理论物理等诸多领域的强有力工具，本文综述了小波理论在地震数据预处理、反演、偏移成像、解释四方面应用研究的最新进展。 相似文献
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地震信号中的随机噪声是一种干扰波,严重降低了地震信号的信噪比,并影响着资料的后续处理和分析.本文根据地震信号中有效信号和随机噪声的差异,结合分数阶B样条小波变换与高斯尺度混合模型提出了一种地震信号随机噪声压制方法.首先利用分数阶B样条小波变换将含噪地震信号映射到最优分数阶小波时频域内,然后对各小波子带系数分别建立高斯尺度混合模型,由贝叶斯方法估计出源地震信号小波系数,最后使用分数阶B样条小波逆变换重构得到降噪后的地震信号.利用本文方法对合成地震记录和实际地震信号进行降噪处理,实验结果表明本文方法能够有效地压制地震信号中的随机噪声,并且较好地保留了有效信号. 相似文献
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Björn Lund Clarence O. Collins Hans C. Graber Eric Terrill Thomas H. C. Herbers 《Ocean Dynamics》2014,64(7):999-1018
The strength of the surface wave signal in marine X-band radar (MR) images strongly depends on range and azimuth (i.e., the angle between antenna look and peak wave direction). Traditionally, MR wave analysis is carried out in a set of rectangular windows covering the radar field of view (FOV). The FOV is typically partially obstructed, e.g., due to the coastline or ship superstructures. Especially for ships that are subject to regular course changes, this results in an increased variability or error associated with wave parameters. Using MR measurements from R/P FLIP, acquired off California during the 2010 US Office of Naval Research (ONR) high resolution air–sea interaction (Hi-Res) experiment, this study quantifies the dependency of the radar-based 2D wave spectrum and parameters on range and azimuth. With the help of reference data from a nearby Datawell Waverider buoy, we propose empirical methods to remove the dependency and we illustrate their efficacy. 相似文献
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为了分析和研究数字地震波信号的频谱分布特征,开发了地震波信号频谱分析软件(CALM P),并对辽宁岫岩地震和山西台网记录到的2001年至2003年的地震进行了分析处理,以期发现数字地震波信号的频谱分布规律。 相似文献
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本文理论分析了电子束沿地磁场穿越均匀、磁化等离子体密度跃变区域时，在弱磁场近似、哨声波激发、低频近似等几种典型情况下电子束流空间电荷波（Space charge wave）向电磁波的转换.先运用小信号假设求得电子束入射进均匀各向异性冷等离子体之后的色散关系和空间电荷波波数，然后借助于电磁波分量和电子束速度的边界条件，求解电子束在等离子浓度发生变化区域激发的波振幅，在几种典型情形下推导出空间电荷波转换为电磁波之间转换系数的近似解，给出了相应波辐射的坡印亭(Poynting)矢量表达式.结果表明，在渡越辐射（Transition radiation）情形下电子束可以在空间等离子体中激发出阿尔芬波（Alfven wave）和哨声波（Whistler wave）.所得结论可用于对主动空间试验结果的分析. 相似文献
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传统的傅里叶变换因缺乏信号局域性的信息,无法对地震波等非平稳信号进行全面描述,时频分析通常是分析非平稳信号较好的工具.本文利用大柴旦地震台记录到的2013年6月5日青海海西5.0级地震波形,采用赵-阿特拉斯-马克时频分布（ZAM）分别研究了该地震P波、S波段的时间-频率特征.研究结果很好地解释了地震波的非平稳性,较全面地展示了地震波的衰减特征. 相似文献
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H.-L. Chen A. R. Rao 《Stochastic Environmental Research and Risk Assessment (SERRA)》1998,12(4):205-222
Cohen and Sweeter (1975) found the 20 to 22-year Hale (double sunspot) cycle signal in the maximum entropy spectra of sunspot
and Atlantic tropical cyclone data. Currie (1996) corroborated and extended their analysis, but he argued that this signal
is the 18.6-year luni-solar tidal constituent. Currie maintains that Cohen and Sweeter mistakenly conjectured that this long
term periodicity was induced by the 20 to 22-year Hale cycle signal. However, no further investigation of periodicity in the
extracted wave forms corresponding to the 18.6-year luni-solar signal was conducted. In this study, we follow Currie's signal
processing procedures to extract the wave forms corresponding to the 18.6-year luni-solar signal. In order to investigate
the periodicity in the extracted wave forms, multi-taper method (MTM) is used for harmonic analysis. Band pass filters are
then designed to extract the wave forms corresponding to the individual components identified in the MTM harmonic analysis.
The investigation results of the monthly precipitation and Palmer's drought severity index (PDSI) data in three of the midwestern
states – Illinois, Indiana and Ohio – show that two periodic components, the 20 to 22-year Hale cycle signal and the other
component with periods between 16.9 and 13.5 years, are identified. The bistability phenomenon, which Currie found in these
wave forms, is more likely to result from the superposition of these two periodic components, rather than from a nonlinear
mechanism. Besides, a periodic component with an approximate period of 33 years is detected. 相似文献
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Xuanhui Yang Yu Jeffrey Gu Ping Shen Xiqiang Liu Zhizhen Zheng 《Pure and Applied Geophysics》2006,163(8):1515-1536
Signal extraction from overlapping seismic records is a common problem in geophysical data analysis. Identification and separation
of multiple seismic arrivals, analysis of large earthquakes as multiple point sources, and calculation of the true yield of
a large nuclear explosion from interfering small explosion, all hinge on our ability to effectively decouple two interfering
wave signals. This paper presents a method for signal separation based on an adaptive filtering technique. We apply a semi-deconvolution
algorithm to overlapping explosion records and S/SKS phase groups, and then perform noise reduction and signal decoupling
under different a priori conditions and assess the stabilities using a variance reduction approach. We demonstrate, through numerical experiments
and analysis of seismic station records, that the adaptive method can be both robust and practical for regional and teleseismic
applications. 相似文献
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Cohen and Sweeter (1975) found the 20 to 22-year Hale (double sunspot) cycle signal in the maximum entropy spectra of sunspot
and Atlantic tropical cyclone data. Currie (1996) corroborated and extended their analysis, but he argued that this signal
is the 18.6-year luni-solar tidal constituent. Currie maintains that Cohen and Sweeter mistakenly conjectured that this long
term periodicity was induced by the 20 to 22-year Hale cycle signal. However, no further investigation of periodicity in the
extracted wave forms corresponding to the 18.6-year luni-solar signal was conducted. In this study, we follow Currie's signal
processing procedures to extract the wave forms corresponding to the 18.6-year luni-solar signal. In order to investigate
the periodicity in the extracted wave forms, multi-taper method (MTM) is used for harmonic analysis. Band pass filters are
then designed to extract the wave forms corresponding to the individual components identified in the MTM harmonic analysis.
The investigation results of the monthly precipitation and Palmer's drought severity index (PDSI) data in three of the midwestern
states – Illinois, Indiana and Ohio – show that two periodic components, the 20 to 22-year Hale cycle signal and the other
component with periods between 16.9 and 13.5 years, are identified. The bistability phenomenon, which Currie found in these
wave forms, is more likely to result from the superposition of these two periodic components, rather than from a nonlinear
mechanism. Besides, a periodic component with an approximate period of 33 years is detected. 相似文献