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101.
瞬变电磁测深法的研究深度 总被引:2,自引:0,他引:2
殷长春 《吉林大学学报(地球科学版)》1992,(1)
研究发现,瞬变测深法研究深度除了与采样时间(采样间隔,起始和终止采样时间等)有关外,还与信号源强度、大地电导率、系统噪音水平以及仪器观测精度等因素有关,文中对研究深度与这些量之间的关系作了数学描述。 相似文献
102.
The terrestrial noise in the differencial data of geomagnetic total field recorded at 21h in North China was fitted by using
the geomagnetic vector data from Beijing Observatory. The terrestrial noise level and its spatial feature in this region was
discussed. A method, which may be useful for justifying the quality of fitting, was provided in this paper. The analysis indicates
that the terrestrial noise is one of the important noise in tectonomagnetic study. It is shown that the susceptibility effect
is quite small and the orientation effect is the main component in the terrestrial noise in North China. The rough spatial
feature of the magnetic anomaly in crustal substance was infered from the spatial feature of terrestrial noise. The measurement
precision and the source noise level of data at 21h in this region were obtained in the analysis of residual noise.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 441–447, 1993. 相似文献
103.
Power spectral characteristics of the seismic activities before and after the seven large earthquake — Haicheng, Tangshan,
Lancang, Longling, Mabian, Puer and Songpan are studied by spectrum analysis method. The results show that they all have continuous
power spectrum and aperiodic behaviour. When the time away from the large earthquake occurrence, the characteristics of the
seismic activities are obviously accompanied by stochastic components. About one year before main shock, the moving orbits
constructed by spectrum amplitudes showed the contracting tendency. And the properties during that time may display as flicker
noise. One’s another time almost mixed whole phase space. But the essence of seismic activities after main shocks is a chaotic
state accompanied with much noises.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 276–281, 1993.
This subject is supported by the Chinese Joint Seismological Foundation. 相似文献
104.
伴随层析成像(Adjoint Tomography)通过求解全波方程来准确模拟地震波在复杂介质中的传播,并利用波形信息来反演地下结构,是新一代的高分辨率成像方法.其中3-D伴随层析成像需要庞大的计算资源,而2-D反演相对更具计算效率.面波和远震体波是研究地壳上地幔速度结构的重要方法,它们对S波速度及Moho面的敏感度不同,通过联合反演,可以得到更为准确的S波速度结构及Moho面.通过两种数据的高度互补性,本文提出基于伴随方法的线性台阵背景噪声面波和远震体波联合成像方法,同时约束台阵下方S波速度结构及Moho面形态.我们将该方法应用到符合华北克拉通岩石圈典型结构特征的理论模型上,测试结果表明联合反演方法优势明显,相比于面波伴随层析成像,能获得更高分辨率的S波速度结构,同时能精准约束Moho面形态.相比于体波伴随层析成像,联合反演能有效压制高频假象,降低波形反演过程中的非线性化程度.本研究有望提供一种更为高效精准的线性台阵成像方法,搭建联合伴随层析成像理论框架,提升岩石圈成像分辨率,并为后续其他类型波形数据的引入提供思路和方法. 相似文献
105.
JPL's BlackJack receiver currently represents the most widely used geodetic grade GPS receiver for space applications. Using data from the CHAMP science mission, the in-flight performance of the BlackJack receiver has been assessed and the impact of various software updates performed during the 2.5 years since launch is described. Key aspects of the study comprise the channel allocation, anomalous data points, and the noise level of the code and carrier data. In addition, it has been demonstrated that the code measurements collected onboard the CHAMP satellite are notably affected by multipath errors in the aft-looking hemisphere, which can be attributed to cross-talk between the occultation antenna string and the primary precise orbit determination antenna. For carrier smoothed 10 s normal points, the code noise itself varies between a minimum of 5 cm at high elevations and 0.5 m (C/A) to 1.0 m (P1, P2) at 10° elevation. Carrier-phase data exhibit representative errors of 0.2 to 2.5 mm. The results of the CHAMP GPS data analysis contribute to a better understanding and possible improvement of the BlackJack receiver and support the design of optimal data editing and weighting strategies in precise orbit determination applications. 相似文献
106.
107.
108.
高密度空间采样地震数据特点分析 总被引:3,自引:0,他引:3
中国陆相沉积盆地的地质结构复杂,储层岩性的多变,需要有高精度的勘探方法。高密度空间采样是提高地震勘探精度的一项新技术。本文简要说明了点激发和点接收技术,分析高密度空间采样的野外工作方法,介绍了Gijs j.o.Vermeer提出的对称采样原理,从波场连续性的角度探讨了高密度空间采样技术。重点分析高密度空间采样数据的特点, 即:高密集的初至波有利于近地表结构的调查,可提高静校正的精度;小偏移距、小点距接收增加了浅层的有效覆盖次数,提高浅层反射的成像精度; 对规则噪声可实现无假频采样,室内的噪声分析和噪声压制的精度随着提高;高密度采集使波场连续性增强,使得各种数学变换的精度提高,有利于不同波场的分离。最后指出高密度空间采样地震勘探技术的难点在于室内数据处理,针对海量数据的分析和处理方法还需要进行深入细致的研究工作。 相似文献
109.
Jianlin Zhu Guangming Zeng 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(2):143-149
Detrended fluctuation analysis (DFA) and power spectrum density are applied to verify the presence of temporal scaling behavior and long-range persistence (LRP) of weekly hydrogen ion deposition (WHD), NO3- and SO42- deposition series in National Atmospheric Deposition Program, USA, for the period 1978–2001. The results show a common scaling behavior for all sites analyzed. Two distinct scaling regions are identified by DFA1, one corresponding to 1 month to 1 year and the other to 1 year to 5 years. The WHD series obey power-law in two temporal regimes respectively with mean DFA1 scaling exponents α
1≈0.68 and α
2≈0.45, implying the presence of LRP in the acid deposition series and there is a tendency for a large deposition event to be followed by another large event, and vice versa. For DFA2–DFA4, however, the annual crossover, which divides the temporal scale into two regimes, disappears gradually with the order q of DFAq increasing, and the two scaling regimes turn to share the same scaling exponent close to α
1. The result indicates that the scaling behavior exits in the two regimes with the same scaling exponent α
1, and LRP prevails during the examined 1-month to 5-years scale. NO3- and SO42- deposition evolve the same way as WHD does, implying the pollutants involving in acid deposition may share some prominent mechanism controlling their evolutions. We ascribe the long-range power-law scaling of acid deposition evolutions to the self-organized critical behavior of atmosphere under pollution stress and it should be considered in the trend prediction of acid deposition as an important factor. 相似文献
110.
In this paper,we analyze the time series of site coordinates of 27 continuously monitoring GPS sites covered bythe Crustal Movement Observation Network of China over the whole country.The data are obtained in the periodfrom the beginning of the observation to the November of 2005.On the basis of data processing,we analyze thepower spectrum density of coordinate component noise at each site and calculate the spectral indexes manifestingthe noise property of each component.The spectral indexes indicate that for most sites,the noise of time series ofeach coordinate component can be addressed by the model of white noise flicker noise;and for a small amountof sites,it can be described by the model of white noise flicker noise random walk noise.We also quantita-tively estimate each noise component in the model by using the criterion of maximum likelihood estimation.Theresult shows that the white noise in the time series of GPS site coordinates does not constitute the main part ofnoise.Therefore,the error estimation of site movement parameters is usually too small,or too optimistic if weconsider the white noise only.Correspondingly,if this factor is not fully considered in explaining these movementparameters,it might mislead the readers. 相似文献