“潜龙二号”自主水下机器人热液探测系统

“潜龙二号”水下自主航行器（QianlongⅡ AUV）为深海资源尤其是海底多金属硫化物调查而设计，其已在西南印度洋脊热液区进行成功的调查运用。本文系统地概述了“潜龙二号”的热液系统探测功能实现、数据管理、快速成图等工作；阐述了如何利用AUV转圈数据有效的校正载体对磁测干扰的。基于“潜龙二号”获取的热液异常，发展了热液喷口快速定位方法。以具体一潜次为例，系统地展示了热液探测数据的处理分析与热液异常定位工作，证实了该方法的有效性。     

Failure Characteristics of Surface Vertical Wells for Methane Extraction During Mining: A Case Study

The failures of surface vertical wells (SVWs) for methane extraction during mining are known to be the main causes of the shortening of the highly efficient drainage periods of the SVWs. Therefore, in order to improve the stability of the SVWs, it is of great significance to accurately investigate the failure characteristics when SVWs are severely destroyed and can no longer extract methane. In this research, a physical simulation experiment was carried out for the purpose of investigating the most possible failure periods, as well as the highest possible failure locations and failure modes of SVWs. This study’s results showed that the displacements of the SVW were constantly changing under the influences of mining stress. After the mine working faces had past the SVWs by more than 157 m, the total displacements reached the maximum, and the SVWs were in the most possible failure periods. During those periods, failure positions of the SVWs are prone to occur at the interfaces between the hard and soft strata; within the thick rock layers; and within the thick-thin-thick strata combination. Among these, the SVWs may suffer from shear slippage at the interface of the hard-soft combined rock layers with relatively large thickness differences; the SVWs may suffer from horizontal shear at the interfaces of the hard-soft combined rock layers with small thickness differences; the SVWs within the thick rock layers may become destroyed by shear slippage actions; and the SVWs in the thick-thin-thick combined rock layers may become distorted by shearing at the interface between the rock layers or blocking within the intermediate thin rock. The results of this research study were verified through the field tests which were conducted in China’s Sihe Coal Mine.

     

海洋声速起伏对声传播及定位精度影响分析

海洋中声速起伏导致水声信道发生变化,进而引起声线到达结构的变化,对水声传播及定位精度产生一定影响。为讨论这一效应,基于TDOA体制建立了考虑声线弯曲的水下目标无源定位模型,分析了声速起伏对水下声传播路径及传播时间的影响,进而研究了声速起伏对水下无源定位测量精度影响程度。结果表明:当水平传播距离较大时,声速剖面起伏对声传播路径及传播时间的影响更为显著;以典型四元阵为例,若基线长度为20 km,接收阵位于水下5 km处,在不考虑其它随机误差影响下,海洋声速起伏造成的声源定位误差量级在0.5 m以内。分析结果有助于更好地利用环境特征优化无源定位测量方案,可为高精度水下无源定位系统设计及精度评估提供依据。     

长江口水沙变化与趋势预测

随着长江流域水土保持、上游水库拦蓄调节、沿江用水增加及气候变化,进入长江口的水沙通量发生改变,入海泥沙量锐减。此外,长江口相继实施了深水航道治理、青草沙水源地、浅滩圈围等大型工程。因此,需要针对长江口水沙变化开展相关研究。对长江口陆相和海相水沙变化规律及趋势、河床容积与泥沙收支变化以及整治工程下分汊河口演变预测等进行了概述,预测了今后10～50年大通站流量、含沙量、输沙量变化以及南北槽的演变趋势,为进一步研究变化条件下的长江口重大工程安全提供基础条件。     

Relationship of Halo CMEs and Solar Proton Events

Coronal Mass Ejections (CMEs) are important sources of Solar Proton Events (SPEs). Their speeds and source region locations have significant effects on the occurrence of SPEs. In this paper, all the halo CMEs observed in recent five years are statistically analyzed. The results show that the fast halo CMEs with small angular distances are more likely to produce SPEs, especially, those halo CMEs with a speed greater than 1200 km s^?1 and an angular distance less than 60°. Three fast halo CMEs with no SPEs caused are elaborately studied. The results show that the ejection direction of the CME's main body and the variation of interplanetary magnetic field also have important impacts on the occurrence of SPEs. Consequently, in the practical daily space environment forecasts, an accurate forecast for SPEs must take various factors into account, such as the eruption speed, source region location, the main-body ejection direction of CMEs, and the interplanetary environment, etc.     

Subduction initiation in the Neo‐Tethys: constraints from counterclockwise P–T paths in amphibolite rocks of the Nagaland Ophiolite Complex,India

High‐P metamorphic rocks that are formed at the onset of oceanic subduction usually record a single cycle of subduction and exhumation along counterclockwise (CCW) P–T paths. Conceptual and thermo‐mechanical models, however, predict multiple burial–exhumation cycles, but direct observations of these from natural rocks are rare. In this study, we provide a new insight into this complexity of subduction channel dynamics from a fragment of Middle‐Late Jurassic Neo‐Tethys in the Nagaland Ophiolite Complex, northeastern India. Based on integrated textural, mineral compositional, metamorphic reaction history and geothermobarometric studies of a medium‐grade amphibolite tectonic unit within a serpentinite mélange, we establish two overprinting metamorphic cycles (M₁–M₂). These cycles with CCW P–T trajectories are part of a single tectonothermal event. We relate the M₁ metamorphic sequence to prograde burial and heating through greenschist and epidote blueschist facies to peak metamorphism, transitional between amphibolite and hornblende‐eclogite facies at 13.8 ± 2.6 kbar, 625 ± 45 °C (error 2σ values) and subsequent cooling and partial exhumation to greenschist facies. The M₂ metamorphic cycle reflects epidote blueschist facies prograde re‐burial of the partially exhumed M₁ cycle rocks to peak metamorphism at 14.4 ± 2 kbar, 540 ± 35 °C and their final exhumation to greenschist facies along a relatively cooler exhumation path. We interpret the M₁ metamorphism as the first evidence for initiation of subduction of the Neo‐Tethys from the eastern segment of the Indus‐Tsangpo suture zone. Reburial and final exhumation during M₂ are explained in terms of material transport in a large‐scale convective circulation system in the subduction channel as the latter evolves from a warm nascent to a cold and more mature stage of subduction. This Neo‐Tethys example suggests that multiple burial and exhumation cycles involving the first subducted oceanic crust may be more common than presently known.     

扩域搜索遗传算法优化马斯京根参数及其应用

马斯京根法作为河道洪水预报的重要方法,参数和系数的率定是关键和难点,直接影响其预报精度。在详细阐述扩域搜索遗传算法基本思想和性能分析的基础上,以模拟结果与实测值的误差最小作为进化目标,直接搜索马斯京根法预报方程系数,获得河道上下游流量关系方程。对黄河下游夹河滩至高村的洪水过程进行研究,传统方法的平均绝对误差为240 m³/s,平均相对误差为0.13;遗传算法的平均绝对误差为95 m³/s,平均相对误差为0.05。结果表明：遗传算法精度明显高于传统方法。在实际应用中,对于河道洪水波的传播规律性变化较大的河道,应根据不同量级洪水来模拟洪水的传播规律,并对相应量级的洪水进行预报。     

深水多波束声呐测深数据精度评估

多波束测深精度评估是水深测量质量控制的重要方面,静态精度评估与交叉测线动态精度评估能够从不同角度表征测深精度,估计测量样本的综合误差。在实际调查作业过程中,由于缺少水深真值,在进行精度估计时缺少可操作性。本文利用Kongsberg EM120型深水多波束系统的测深数据,基于某一区域的重复测量数据,应用中央波束的水深数据进行静态精度分析;通过引入网格化方法,进行动态水深精度评估分析,并通过偏差分析揭示测量样本的误差分布特征。结果表明,中央波束水深数据静态精度评估与基于网格化方法的动态精度评估具有实际可操作性,其结果能够有效估计测深的综合误差;重复测量数据的偏差分析能够有效展示误差的分布特征。     

Tourism sectorization opportunity spectrum model and space partition of tourism urbanization area: a case of the Mayangxi ecotourism area,Fujian province,China

Nowadays, tourism has become an increasingly significant driving force of modern urbanization in China. However, it has caused varieties of problems, such as resource unreasonable utilization, society unfair play, and environment pollution, etc. Thus, the establishment of an efficient and sustainable space partition model for tourism urbanization, from the geographical perspective, is highly necessary and urgent. Herein, a new evaluation model of tourist town space, referred to as Tourism Sectorization Opportunity Spectrum (TSOS), is established on the relationships between production-living-ecology spaces. TSOS is a kind of quantitative evaluation model involving such factors as urban living area, ecological conservation area and the tourism industry. Furthermore, the analysis of quantitative production-living-ecology spatial overlap has been utilized for space division in a tourism urbanization area. This paper, using both the TSOS model and GIS technology, analyzes the spatial restructure of the Mayangxi ecotourism area. The result demonstrates that tourism industrial space takes the Shanchong Village as a core which shows a pattern of local regional agglomeration and a fuzzy edge extending along the entire Mayangxi River. The urban living area should be consolidated in the Shili village with the supporting facilities and living space for tourism. In addition, Tianzhu Mountain forest park should be the key environmental protection area. The case study on the Mayangxi ecotourism area verifies that the TSOS model has strong operability. Therefore, TSOS model provides a scientific foundation for the space reconstruction of new urbanization area, and an effective tool for optimizing the space partition of a tourism urbanization area.     

新疆阿合奇地区志留系砂岩地球化学特征及大地构造背景*

塔里木板块西北缘沉积地层的研究,对于恢复南天山洋的演化过程有重要意义。文中利用岩石地球化学的手段,对新疆阿合奇地区志留系砂岩进行物源和构造背景分析。研究表明,阿合奇地区志留系砂岩样品的SiO₂含量范围变化较大,为61.97%~93.91%,平均含量为76.76%;稀土元素球粒陨石标准化配分型式为右倾型,(La/Yb)_N值较高,δEu值较低,Ce异常不明显。中-顶志留统塔塔埃尔塔格组砂岩的成熟度高于下志留统柯坪塔格组。地球化学物源分析图解和大地构造背景判别表明: 研究区沉积物源区逐渐由活动型向稳定型转换,下志留统部分沉积物来自于火成岩物源区,具有主动大陆边缘和大陆岛弧性质;中-顶志留统沉积物全部来自于成熟大陆的石英岩沉积物源区。结合广泛分布的奥陶系-志留系平行不整合,认为晚奥陶世研究区为活动大陆边缘,南天山洋盆向南俯冲到塔里木板块之下;早志留世,向南俯冲结束,研究区大地构造背景开始由活动大陆边缘向稳定的被动大陆边缘转换,来自活动型物源区的沉积物逐渐减少,稳定型物源区的碎屑物质逐渐增多;中-末志留世,研究区构造背景完全转变为被动大陆边缘,碎屑物质全部来自于稳定型物源区。上述成果表明,南天山洋的演化过程中确实存在双向俯冲。