广东新丰江水库地震垂向引潮力的调制作用研究

按照前人对新丰江水库地震序列特征的研究,以1965年为界将新丰江水库地震序列分为前期和后期,对前期(M<,s>≥4.3)和后期(M<,s>≥4.2)地震垂向引潮力的触发特征进行了研究.发现前期15次M<,s>≥4.3级地震发震时刻垂向引潮力的方向处于向下区间的有12次,占80%;其中M<,s>≥4.5级地震全部都处于垂...     

Molecular diversity and biogeography of benthic microeukaryotes in temperate seagrass (Zostera japonica) systems of northern China

The productivity and health of seagrass depend on the combined inputs of nutrients from the water and sediments in which they grow and the microbiota with which they live intimately. However, little is known about the composition and diversity pattern of single-celled benthic eukaryotes in seagrass meadows. Here, we investigated how the structure and diversity of the benthic microeukaryotic community vary with respect to season, location, and seagrass colonization, by applying 18S rRNA gene amplicon sequencing for 96 surface sediment samples that were collected from three different seagrass habitats through four seasons. We found that benthic microeukaryotic communities associated with seagrass Zostera japonica exhibited remarkable spatial and seasonal variations, as well as differences between vegetated and unvegetated sediments. Diatoms and dinoflagellates predominated in the benthic microeukaryotic communities, but they were inversely correlated and displaced each other as the dominant microbial group in different seasons or habitats. Mucoromycota was more prevalent in vegetated sediments, whereas Lobulomycetales and Chytridiales had higher proportions in unvegetated sites. Total organic carbon and total organic nitrogen were the most important environmental factors in driving the microeukaryotic assemblages and diversity. Our study expands the available knowledge on the biogeographic distribution patterns and niche preferences for benthic microeukaryotes in seagrass systems.     

余震活动机理研究综述

从介质和应力的不均匀性、力学加载、流体侵入及应力腐蚀、速率-状态依从等几方面对余震活动机理研究进行了综述。已有的研究表明,介质和应力的不均匀性是余震产生的基本前提。瞬时蠕变和余滑观点能够从力学的角度解释震后极短时间内余震的快速衰减,而应力松弛过程更倾向于解释长期余震的活动特征。流体侵入及应力腐蚀在一定的条件下控制着余震的演化过程。受主震应力扰动影响的断层间的相互作用始终存在于余震的活动过程之中。各类模型和理论解释都在一定程度上寻求与G-R关系和修改的大森公式两个基本幂律关系的一致性。     

宁夏灵武、吴忠地区4次地震序列的时间分维特征

本文采用标度变换法分析了宁夏灵武、吴忠地区1971年以来发生的、有较完整的仪器记录的4次中强地震序列的时间分维D_0,发现前震序列或双震序列的第2次主震前的地震时间分维低于余震序列,序列的P值及b值亦具同步变化。初步认为,研究地震序列的时间分维结构可能有助于对其短期趋势的估计。本文还对有关问题进行了讨论。     

内蒙中部地区不同生态区土地利用 格局分布特征

土地利用变化对全球变化和可持续发展有着深刻的影响,同时生态背景因素对土地利用变化也有着相应的反馈关系。采用单元匹配和空间叠加分析的方法,分析了内蒙古中部地区不同自然生态区土地利用空间分布格局特征。其结果表明：不同的生态因素对土地利用空间分布的约束状况不同,土地利用在数量结构和空间格局两个方面存在很强的地带性差异。     

新疆近期两次地震序列的时间信息维特征

本文以新疆两次中强地震的余震序列为例,探讨地震序列不均勻时间分布的分形特征。对其信息维的测算表明,无标度区范围基本稳定,同一时间段内信息维数随震级下限的升高略有降低;而对相同震级下限的样本群而言,不同时段的信息维数具有一定的差异。通常是强余震活动结束之后的信息维数略高于强余震活动期间的信息维数。这一特点对大震后地震趋势的合理估计具有积极意义。     

Understanding of the Effect of Climate Change on Tropical Cyclone Intensity: A Review

The effect of climate change on tropical cyclone intensity has been an important scientific issue for a few decades.Although theory and modeling suggest the intensification of tropical cyclones in a warming climate,there are uncertainties in the assessed and projected responses of tropical cyclone intensity to climate change.While a few comprehensive reviews have already provided an assessment of the effect of climate change on tropical cyclone activity including tropical cyclone intensity,this review focuses mainly on the understanding of the effect of climate change on basin-wide tropical cyclone intensity,including indices for basin-wide tropical cyclone intensity,historical datasets used for intensity trend detection,environmental control of tropical cyclone intensity,detection and simulation of tropical cyclone intensity change,and some issues on the assessment of the effect of climate change on tropical cyclone intensity.In addition to the uncertainty in the historical datasets,intertwined natural variabilities,the considerable model bias in the projected large-scale environment,and poorly simulated inner-core structures of tropical cyclones,it is suggested that factors controlling the basin-wide intensity can be different from individual tropical cyclones since the assessment of the effect of climate change treats tropical cyclones in a basin as a whole.     

分形维数的一种数值计算及统计检验方法

基于分形维数的原始定义，本文给出一种维数的数值计算方法。若被测量对象在某一标度范围内确具有统计意义上的标度不变性，则该方法能够较好地得到所需精度的维数计算结果并进而反推“无标度区”范围。在假设维数集｛ｂｋ｝服从正态分布的前提下，引入柯氏检验方法对（ｂｋ｝样本分布的一致性进行检验，以此判断｛ｂｋ｝中是否具有“异常值”存在，并由标准化极差检验法对｛ｂｋ｝中“异常值”进行检测并剔除，其目的是在“直观判定”的基础上对维数作进一步的精确计算及对“无标在区”作进一步的精确界定．本文方法的一个显著特点是所有判断及统计检验皆针对最终结果（维数）。人造数据的应用检验亦表明了该方法的客观实用性．     

近期华北地震大形势的统计分析

文章在３－５年较长时间尺度概率估计的前提下，力争对未来较短时期（１－２年）各区，带地震活动趋势进行定量分析，特别着重于地震总活动水平的比较及年量大震级的预测。     

利用附加系统参数的GPS-InSAR综合形变模型建立三维形变场

在有效融合GPS与InSAR两种对地观测技术提高地表三维形变监测精度时,针对InSAR监测结果中可能存在的系统偏差,建立了附加系统参数的综合形变分析模型。该模型以高精度的GPS观测数据作为强约束,将InSAR数据中的系统误差综合影响用函数拟合的方法进行补偿。模拟数据和实测数据计算表明,附加系统参数的综合形变分析方法在E、N、U3个方向的精度都有所提高,其中以U方向最为显著。