顾及季节性变化的日本区域加权平均温度建模

利用2014~2018年的ERA-Interim数据建立适用于日本区域的加权平均温度模型,分析其误差并进行季节性改正。结果表明：1）建立的线性加权平均温度模型精度比Bevis模型提高约16%;2）线性模型的残差时间序列存在季节性变化,因此对模型进行季节性改正,改正后的模型精度比Bevis模型和线性模型提高约37%和25%;3）将3种模型与探空站积分Tm进行比较,进一步说明季节性改正后模型的优越性。     

Detailed seismicity mapping of the Altai-Sayan zone using large averaging areas

An improved technique is suggested for quantifying seismic activity over averaging areas of an arbitrary size. The example of the Altai-Sayan seismic zone is used to substantiate the choice of a 1° N × 2° E averaging area instead of the traditional one of 40×40 km². Maps compiled with averaging areas of different sizes can be spliced and correlated using a correction coefficient estimated in different models. The new seismicity map of the Altai-Sayan area covers more than 90% of the territory and provides a generalized image of activity being advantageous over the classic maps as it allows better correlation of regional seismicity with the tectonic setting. With larger averaging areas and, correspondingly, a greater amount of data in each area, one can obtain time series of seismic activity to be analyzed using mathematical statistics as a basis for mathematical modeling and simulation of the seismic process.     

Precise temperature monitoring in boreholes: evidence for oscillatory convection? Part II: theory and interpretation

In the previous part of this work (Cermak, Safanda and Bodri, this volume p.MMM) we have described experimental data and quantified the heterogeneity features of the microtemperature time series. The spectral analysis and the local growth of the second moment technique revealed scaling structure of all observed time series generally similar and suggested the presence of two temperature forming processes. The longer-scale part can be attributed to the heat conduction in compositional and structural heterogeneous solid rocks, further affected by various local conditions. Short-scale temperature oscillations are produced by the intra-hole fluid convection due to inherent instability of water column filling the hole. Here we present how the observational evidence is supported by the results of the computer simulations. The exact modes of intra-hole convection may be different, ranging from quasi-periodic (“quiescent”) state to close of turbulence. As demonstrated by numerical modeling and referred on laboratory experiments, at higher Rayleigh numbers the periodic character of oscillation characteristic for “quiescent” regime is superseded by stochastic features. This so called “oscillatory” convection occurs due to instability within the horizontal boundary layers between the individual convectional cells. In spite of the fact that the basic convective cell motion is maintained and convection is characterized by slow motion, the oscillatory intra-hole flow and corresponding temperature patterns exhibit typical features of turbulence. The idea of boundary layer instability as a source of stochastic temperature fluctuations could explain many distinct features of borehole temperatures that previously cannot be interpreted.     

冀中坳陷武清凹陷苏50井石炭-二叠纪煤系的成烃演化

基于对武清凹陷苏50井的石炭-二叠纪煤系的构造—埋藏史研究,结合磷灰石裂变径迹测试及矿物包裹体分析,运用EASY%Ro数值模拟技术,研究了苏50井石炭-二叠系烃源岩的生烃演化历史,揭示了苏50井处石炭-二叠系烃源岩曾发生过3次重要的生烃作用过程,分别发生在海西-印支期、燕山期与喜马拉雅晚期,主要生烃作用发生在喜马拉雅晚期,并指出武清凹陷是华北石炭-二叠系煤成气勘探的有利地区之一。     

利用GNSS数据分析大港验潮站地壳沉降

青岛大港验潮站的地壳沉降关系到该站平均海平面的绝对变化,因而也就关系到我国高程基准面的变化。本文利用青岛GNSS基准站约10年的观测数据对该站的地壳沉降变化进行分析。首先将青岛GNSS基准站纳入由50个国际IGS站和43个国内陆态网络基准站组成的全球网中,进行单日松弛解和单日约束解解算,获得该站坐标时间序列。然后对该站垂向坐标时间序列进行分析,利用粗差探测、偏差探测、趋势项分析、频谱分析等方法对粗差、偏差、趋势项和周期项进行探测、分析,并通过时间序列模型估计获得时间序列中的周期项振幅和偏差估值。分析表明青岛GNSS基准站垂直方向近一段时间未发现存在显著性的地壳沉降变化,但受到比较明显的周年和半周年周期变化影响。结合青岛大港验潮站验潮数据分析结果得出结论:青岛大港验潮站平均海平面的绝对上升速率是1.62mm/a。     

小波分析在垂向海潮特征信息去噪研究

目前国内外许多学者利用沿海GPS站点的高精度坐标时间序列进行海潮特征信息的提取研究,已取得一定成果,但高精度坐标时间序列中不可避免地存在许多噪声,极大影响海潮特征信息的提取。基于日本GMSD站的67d的高精度PPP坐标时间序列,利用小波分析进行去噪实验,经FFT变换后,将提取的结果与FES2004海潮模型的特征值比较。实验结果表明:经小波分析后,GPS站点的时间序列精度得到提高;经小波去噪后的反演精度均有不同程度的提高,最多达到0.14mm,而海潮特征值的量级为厘米级或者亚厘米级,说明小波分析对海潮特征值的提取精度有明显提高。     

雷达卫星影像中输电导线散射斑的相位时间序列稳定性分析

分析输电导线散射斑相位的几何关系,选取20幅时间跨度约为1年的TerraSAR条带模式影像,对其中两基铁塔之间6条输电导线形成的散射斑相位时间序列进行分析。文中统计分析构成导线散射斑像元的相位离散度,其标准差约为0.2弧度,表明单个散射斑相位稳定。选取铁塔顶部点的导线散射斑为参考点,与另外5个导线散射斑做差分相位时间序列分析,分析导线之间高程差的理论计算值与实际值的一致性。分析结果显示,导线散射斑差分相位序列的波动可达2弧度以上,与导线间高程差产生的相位不一致。     

灰色-时序组合模型在地表变形预测中的应用

通过对某地铁监测点小波去噪后的数据建立灰色预测模型,分析了灰色预测的优缺点,针对灰色预测对波动性数据预测的不足,建立了灰色-时序组合模型。首先,利用灰色模型提取时间序列中的趋势项;然后,用时序模型对残差项进行建模分析,兼顾了数据的趋势性和波动性,弥补了灰色预测的不足,提高了预报精度。     

FFT在变形监测中的应用与分析

在变形监测中获取的观测数据可以看作是时间与空间上的一组变形信号,一般该信号都会呈现趋势性,隐藏其中的周期性不易被发现;利用FFT对其拟合后的残差和小波分解后的高频信号进行变换与分析,通过时间序列分析对其分析结果建模得到短期的预测、预报,效果比较理想。