联合BDS/GPS的北斗广域差分实时电离层延迟格网改正方法研究     

房成贺  陈俊平  兰孝奇  张磊 《大地测量与地球动力学》2019,39(2):169-177

研究并实现中国区域北斗广域差分实时电离层延迟格网改正算法，针对北斗单系统实时建立电离层延迟格网的不足，提出联合BDS/GPS的北斗广域差分实时电离层延迟改正方法。比较BDS、GPS以及BDS/GPS观测的实时电离层延迟格网，并利用北斗单频单点伪距定位进行精度验证。结果表明，在有效格网点覆盖充足的地区，BDS与GPS实时电离层延迟格网定位效果相当；而联合BDS/GPS观测的实时电离层延迟格网极大提高了偏远地区的单频定位精度与可定位历元数，也使原本单系统格网覆盖充足的地区定位效果得到进一步增强和稳定。  相似文献   

利用短期静态PPP结果反演海潮负荷位移     

魏国光  王琪洁  彭葳  郭良琦 《大地测量与地球动力学》2019,39(6):607-612

采用香港11个GPS测站的观测资料进行1 h、2 h、3 h和4h静态PPP解算，获得4组PPP坐标序列，利用调和分析求取11个测站处8个主要分潮的负荷位移参数（振幅和相位），将其与海潮模型计算的负荷位移参数进行对比，并比较分析PPP反演值与海潮模型值改正海潮负荷信号的效果。结果表明，垂直和水平方向上，不同PPP结果反演8个分潮的负荷位移分别具有约5 mm和7 mm的差异；PPP反演8个分潮垂向负荷位移优于全球海潮模型，但水平方向上的反演效果稍弱。  相似文献   

利用InSAR资料反演宁洱Ms6.4地震震源参数及库仑应力变化     

陈晨月  冯光财  高华  杨怀宁 《大地测量与地球动力学》2019,39(3):295-301

首先利用ALOS PALSAR数据，通过D-InSAR技术获取2007-06-03云南宁洱MS6.4地震的同震形变场，然后基于Okada弹性半空间位错模型反演该地震的断层几何以及精细滑动分布，最后计算宁洱地震后周边断层的静态库仑应力变化。结果表明，形变主要集中在西盘，最大视线向形变量为51.6 cm；反演得到的震源位置为23.05°N、101.02°E，深度3 km，断层走向145°，倾向49.5°，平均滑动角153°，发震断层为NNW向普洱断裂，断层活动以右旋走滑为主，兼具逆冲分量；断层面最大滑动量为1.2 m，反演得到的震级为MW619。基于库仑应力场发现，磨黑断裂处于库仑应力增加区域，而2014年景谷地震位于负值区域。结合实地考察资料和反演结果表明，宁洱地震为浅源地震，但断层并未出露地表。  相似文献   

基于GPS和水准数据的微粒群算法联合反演祁连山北缘断裂三维滑动速率     

刘杰 《大地测量与地球动力学》2019,39(9):906-909

将微粒群算法与位错理论模型相结合，采用中国地壳运动观测网络提供的青藏高原地区2001~2004年GPS测量数据和2000~2006年水准测量数据，通过常规定权和附有相对权比的方法对祁连山北缘断裂的三维滑动速率进行联合反演，并与蚁群算法反演结果进行对比。结果表明，微粒群算法收敛速度快、稳定性高，结合经典位错理论模型，是一种可以有效求解断层三维滑动速率反演问题的优化算法，在大地测量反演领域极具应用潜力。  相似文献   

Inter- and intra-annual trend analysis of water level and flow in the middle and lower reaches of the Ganjiang River,China     

Di Zhu  Yue Ben  Xinfa Xu 《水文科学杂志》2020,65(12):2128-2141

ABSTRACT

The Ganjiang River is the largest tributary of Poyang Lake in China, and its hydrological regime variation greatly affects the utilization of regional water resources and the ecological environment of the lake. In this study, a novel trend analysis method, the Moving Average over Shifting Horizon (MASH), was applied to investigate the inter- and intra-annual trends of flow and water level from 1976 to 2016 at the Xiajiang and the Waizhou hydrological stations in the Ganjiang River. The Significant Change Rate Method (SCRM) was proposed to determine the MASH averaging parameters. The trend analysis results show a statistically significant decrease in water level series throughout the year and the relationship of flow and water level have changed greatly at the Waizhou station. The sediment load reduction, large-scale sand mining and water level decrease of Poyang Lake are identified as the main causes for the water level decrease.  相似文献   

黔北正安地区五峰组—龙马溪组页岩气地质特征及有利区预测     

贺永忠  向坤鹏  安亚运  易成兴  杨忠琴  于宁 《中国地质调查》2020,7(3):21-29

为明确黔北正安地区上奥陶统五峰组至下志留统龙马溪组的页岩气地质特征,充分应用页岩气地质调查、重磁电、二维地震、地质调查井及测试分析等工作方法,开展黔北正安地区1:5万页岩气基础地质调查,对五峰组至龙马溪组富有机质页岩的分布、沉积环境、有机地球化学、岩石矿物、储集性能及含气性等特征进行分析研究,结果表明: 研究区五峰组—龙马溪组富有机质页岩为深水陆棚相沉积,主要分布有安场向斜、斑竹向斜和泥高向斜,厚度14.5~55 m,埋深0~3 200 m; 有机碳(TOC)含量1.0%~4.0%,有机质镜质体反射率(R_o)为1.82%~2.23%,有机质类型以Ⅰ型干酪根为主; 岩石主要由石英、长石和黏土矿物组成,脆性矿物含量高,一般大于50%; 孔隙度为2.03%~3.89%,渗透率为0.35×10^-5~1.86×10^-5μm²,表现为低孔、特低渗的特征; 最高含气量为2.88 m³/t,显示出较好的含气性特征。综合分析和评价圈出3个页岩气聚集有利区,分别为安场区块、斑竹区块和泥高区块,这为研究区页岩气进一步勘探开发指明了方向。  相似文献   

Radiolarian‐based study on the fabric and the formation process of the Early Cretaceous mélange near Zhongba,Yarlung–Tsangpo Suture Zone,southern Tibet     

Xin Li  Atsushi Matsuoka  Yalin Li  Yushuai Wei  Chengshan Wang 《Island Arc》2019,28(1)

The Yarlung–Tsangpo Suture Zone (YTSZ), as the southernmost and youngest among the sutures that subdivides the Tibetan Plateau into several east–west trending blocks, marks where the Neo‐Tethys was consumed as the Indian continent moved northward and collided against the Eurasian continent. Mélanges in the YTSZ represent the remnants of the oceanic plate through subduction and collision. Mélanges are characterized by a highly sheared volcanoclastic or siliceous mudstone matrix including blocks of chert, claystone, and basalt. Detailed radiolarian analyses are conducted on the mélange near Zhongba County. Macroscopic, mesoscopic, and microscopic observations are combined in order to elucidate the relationships among age, lithology, and structure of blocks in the mélange. Reconstructed ocean plate stratigraphy includes Lower Jurassic limestone within the chert sequence accumulated at a depth near the CCD (Unit 2), Upper Jurassic thin‐bedded chert interbedded with claystone deposited in the wide ocean basin (Unit 3), and Lower Cretaceous chert with siliceous mudstone (Units 4 and 5), representing the middle parts of ocean plate stratigraphy. The results highlight the fabric of brecciated chert on mesoscopic scale, which is thought to be due to localized overpressure. The formation of mesoscopic and microscopic block‐in‐matrix fabrics in the mélange is proposed for the chert and siliceous mudstone bearing different extents of consolidation and competence during the progressive deformation of accreted sediments at shallow‐level subduction.  相似文献   

基于区域水准和跨断层资料分析云南地区地壳形变     

徐东卓  苏广利  王世进  朱传宝  孙非非 《震灾防御技术》2019,14(1):118-128

为了获取云南地区现今地壳形变和断层活动特征，收集了云南地区1992—2016年的2期精密水准观测资料，采用基于GNSS连续站垂直形变资料约束的平差方法，对区域整体地壳垂直形变特征进行了分析，结果显示滇西北区域地壳整体表现为隆升，垂向速率为2—3mm/a，滇南区域显示地壳沉降速率为-1—-2mm/a，并在下关—永胜和思茅—景谷一带存在地壳形变高梯度带。收集了该地区30多年的跨断层场地观测资料，计算了所跨断层的三维活动量，得出了断层现今活动状态和异常特征，认为滇西北和滇中南地区的场地多数表现出异常活动的现象，其中楚雄、剑川和永胜的监测断层现今表现出与地质背景相反的走滑和拉张特征，峨山、建水和通海场地所处断层在张压性质上与地质背景相反。结合区域水准和跨断层观测分析结果，从“面”和“线”上得出滇西北和滇中南地区存在地壳形变和断层活动异常，构造应力积累较高的结果，加之缺震背景显著，认为应关注该区域中强地震的危险性。  相似文献   

Intra-survey reservoir fluctuations – implications for quantitative 4D seismic analysis     

Veronica Omofoma  Colin MacBeth  Hamed Amini 《Geophysical Prospecting》2019,67(2):282-297

During the time taken for seismic data to be acquired, reservoir pressure may fluctuate as a consequence of field production and operational procedures and fluid fronts may move significantly. These variations prevent accurate quantitative measurement of the reservoir change using 4D seismic data. Modelling studies on the Norne field simulation model using acquisition data from ocean-bottom seismometer and towed streamer systems indicate that the pre-stack intra-survey reservoir fluctuations are important and cannot be neglected. Similarly, the time-lapse seismic image in the post-stack domain does not represent a difference between two states of the reservoir at a unique base and monitor time, but is a mixed version of reality that depends on the sequence and timing of seismic shooting. The outcome is a lack of accuracy in the measurement of reservoir changes using the resulting processed and stacked 4D seismic data. Even for perfect spatial repeatability between surveys, a spatially variant noise floor is still anticipated to remain. For our particular North Sea acquisition data, we find that towed streamer data are more affected than the ocean-bottom seismometer data. We think that this may be typical for towed streamers due to their restricted aperture compared to ocean-bottom seismometer acquisitions, even for a favourable time sequence of shooting and spatial repeatability. Importantly, the pressure signals on the near and far offset stacks commonly used in quantitative 4D seismic inversion are found to be inconsistent due to the acquisition timestamp. Saturation changes at the boundaries of fluid fronts appear to show a similar inconsistency across sub-stacks. We recommend that 4D data are shot in a consistent manner to optimize aerial time coverage, and that additionally, the timestamp of the acquisition should be used to optimize pre-stack quantitative reservoir analysis.  相似文献   

基于F-范数的不确定性平差模型的解算方法     

鲁铁定  朱国红 《大地测量与地球动力学》2018,38(6):557-561

为提高基于F-范数的不确定性平差模型的解算效率，给出直接迭代算法进行参数估计。该算法无需SVD，解算过程简单且易于编程计算，同时给出迭代不收敛时的SVD-解方程算法。二元线性拟合及沉降观测AR模型的算例结果表明，这2种算法正确可行，与SVD-迭代算法具有等价性。当迭代收敛时，宜使用直接迭代算法，收敛速度更快，解算效率更高；当迭代不收敛时，可釆用SVD-解方程算法。  相似文献