总强度磁异常各阶垂向导数换算新方法

磁异常垂直导数换算在磁性目标解释推断过程中具有重要意义。分析了总强度磁异常各阶垂向导数频率转换因子的滤波特性,指出常规傅立叶变换法在求解总强度磁异常各阶垂向导数时,观测数据中高频噪声会显著放大,甚至会淹没掉真实信息。从理论上证明了总强度磁异常沿垂直方向的积分和各阶导数均为调和函数,在此基础上,提出联合采用空间域和频率域运算求解其沿垂直方向的各阶导数。该方法的基本思路是：利用频率域转换关系,计算平面上总强度磁异常沿垂直方向的积分值;选择三点二阶中心差分或双三次样条曲线函数法计算总强度磁异常垂向积分值沿水平方向的二阶导数;最后将二阶水平导数代入拉普拉斯方程求解出总强度磁异常的垂向一阶导数;以总强度磁异常及其垂向一阶导数沿水平方向的二阶导数为基础,结合拉普拉斯方程,可进一步求解出总强度磁异常任意阶垂向导数。同时,为了研究提出方法的有效性,采用球体磁场模型进行验证,并首次推导了地磁场方向和磁化强度方向不一致时,球体总强度磁异常沿垂直方向的一阶和二阶导数表达式。经研究表明：提出的方法换算得到的垂向导数结果精度明显优于常规傅立叶变换法换算结果,且具有较强的抗噪能力,尤其是在计算高阶导数时效果更加明显。     

用最小二乘两步迭代法求解磁性球体几何与磁性参数

通过对常规最小二乘法在求解磁性球体参数过程中产生发散解的原因分析表明:非线性方程组中待定参数过多,特别是角度参数,是影响最小二乘法收敛性的主要因素.为此,提出将磁异常三分量作为观测值,用矢量磁矩作为待定参数,以替代磁化强度磁倾角和磁偏角,从而消除了非线性观测方程中的角度参数影响.根据观测值与磁矩的线性关系以及磁性球体中...     

利用水深不确定度探测测深异常值的方法

利用最小二乘支持向量机(LS-SVM)合理地构造出海底趋势面关键在于训练样本的选取.在构造海底趋势面的过程中,提出并实现了一种基于不确定度优化训练样本的方法.为了检验该方法的有效性,选取实测的多波束测深数据进行验证,并与趋势面滤波法进行比较.结果表明,该方法能有效地抑制较大偏差训练样本的影响,构造的海底趋势面更为合理,...     

浅谈利用激光点云数据制作DEM

利用摄影测量方式获取DEM数据生产周期长、费用高、效率低、高程点获取的密度低。机载雷达集成GPS、IMU、激光扫描仪、数码像机等光谱成像设备,作为精确、快速地获取地面三维数据的工具已得到广泛的认同。结合项目研究与试验,根据实际生产经验,介绍TerraSolid系列软件的模块功能,以及利用点云数据制作DEM的技术流程和方法。     

Detection and Attribution of Changes in Summer Compound Hot and Dry Events over Northeastern China with CMIP6 Models

Northeastern China has experienced a significant increase in summer compound hot and dry events (CHDEs), pos- ing a threat to local agricultural production and ...     

豫东地区中深孔厚覆盖地层钻探套管护壁和泥浆护壁效果对比

阐述了河南省新蔡县焦庄铁矿预查钻孔施工工艺和河南省睢县煤矿预查太康县煤孔施工工艺,通过对比2个矿区施工的经验教训,分析了套管护壁和泥浆护壁在豫东地区的适应性。     

西藏昌都妥坝煤田沉积环境与聚煤规律

通过对妥坝煤田内沉积剖面的系统研究分析,对妥坝煤田的沉积相进行总结,判断煤田的沉积环境,恢复了妥坝煤田二叠世构造一岩相古地理格局。在认真研究妥坝煤田控煤因素,特别是控煤沉积环境及控煤构造样式基础上,研究后期地质事件所诱发的主要构造活动对煤层的影响,剖析了该煤田的主要聚煤规律。     

琼东南盆地陵南低凸起深水钻井岩心的稀土元素地球化学特征及其意义

A geochemical analysis of rare-earth elements(REEs) in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the purpose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both ∑REE and ∑LREE(LREE is short for light-group REEs) fluctuate in a relatively wide range, while ∑HREE(HREE is short for heavy-group REEs) maintains a relatively stable level. With the stratigraphic chronology becoming newer, both ∑REE and ∑LREE show a gradually rising trend overall. The ∑REE of the core is relatively high from the bottom of Yacheng Formation(at a well depth of 4 207 m) to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China's neritic sediments and loess, with significant "continental orientation". The ∑REE of the core is relatively low in the lower part of Yacheng Formation(at a well depth of 4 207–4 330 m), as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrichment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift areas; the continental margin materials from the north contributed only insignificantly; the provenance developed to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement(34–25 Ma BP, early expansion of the South China Sea), Baiyun Movement(23 Ma BP), late expansion movement(23.5–16.5 Ma BP), expansion-settlement transition, and other important events are all clearly recorded by the geochemical characteristics of REEs in the core.     

涨落潮历时时间不等显著海区的水位改正问题

在涨潮、落潮历时时间不等显著的特殊海区实施水深测量水位改正,不合理的计算潮时差将与实际产生明显差异。分析了涨落潮历时时间不等产生的原因,推导了涨落潮历时时间的近似计算公式,为保证水深测量成果质量,提出了在类似海区应逐日分别计算涨潮和落潮时段的潮时差以实施较合理水位改正。     

GPS控制网在建立整合矿井近井点中的应用分析

结合建立整合矿井近井点任务,阐述GPS网布设的主要准备工作、外业施测、内业处理、精度评定、成果可靠性分析,为建立井下首级测量控制系统提供了高精度的平面起算依据,对整合矿井的安全生产具有重要意义。