海洋信息技术的发展与思考

海洋约占地球表面的71%,是人类赖以生存的资源宝库。目前海洋信息技术在全局统筹和共享安全等方面仍存在不足。为科学规划和开发利用海洋并为海洋科学发展提供数据应用平台,文章通过梳理国际国内海洋信息技术的发展历程,结合现代海洋科学与信息技术,提出海洋信息技术建设的相关思考。未来的海洋信息技术将呈现更加高效、智能、实时、可视和共享安全的特征,实现智慧海洋、美丽海洋和生态海洋的伟大梦想。     

丹霞山国家珍稀濒危保护植物丹霞梧桐空间分布的微地貌环境特征研究

以广东丹霞山狮子岩—阳元山景区为研究地,以国家珍稀濒危保护植物丹霞梧桐(Firmiana danxiaensis)的空间分布为研究内容,通过实地考察获取其空间分布的数据（经纬度、海拔、坡度和坡向等）,利用ArcGIS10.0在精度为1 m的DEM地形数据上进行空间分析,总结丹霞梧桐空间分布的微地貌环境特征。研究发现：① 研究区丹霞梧桐主要分布在海拔180 m等高线穿过坡度60o附近的土壤比较贫瘠的垂直节理或水平层理比较发育的崖壁上,并与圆叶小石积(Osteomeles subrotunda)、忽地笑(Lycoris aurea)、卷柏(Selaginella tamariscina)等植物伴生,属于比较耐旱的崖壁植物;② 丹霞梧桐的空间分布不受坡向因素的严格制约,坡度和海拔是影响丹霞梧桐分布的2个重要因素。根据以上分布规律,可以推测180 m等高线穿过坡度60o地带的丹霞山其他崖壁地带,亦可能会有丹霞梧桐的分布,并建议在目前已经发现丹霞梧桐分布比较集中的狮子岩东南坡,设立国家珍稀濒危保护植物丹霞梧桐重点保护带。     

Preliminary study on weathering and pedogenesis of carbonate rock

South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples, which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South China. Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research Project (Grant No. 95pre-39).     

地震烈度仪数据传输协议

中国地震烈度速报与预警系统建设即将全面启动,面对未来地震预警系统中大量地震烈度仪的接入,为了方便数据的传输、汇集、共享、使用和管理,设计一种地震烈度仪数据传输协议。本文介绍烈度仪数据传输协议设计思想和特点,并给出一种参考实现,重点表述各个模块的功能和逻辑关系。     

The effect of seafloor topography in the Southern Ocean on tabular iceberg drifting and grounding

Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system. Seafloor topography is the key factor that affects the drifting and grounding of icebergs, but it has not been fully investigated. This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University. The results highlight the following points. (1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m. The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front (water depth of approximately 500 m). (2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28% of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery (3.62 million km²). Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula. The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km (in water depths of less than 800 m) accounts for 74% of the sea area. (3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m (R=0.85, P<0.01). This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.     

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

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。     

Scattering pattern analysis and true-amplitude generalized Radon transform migration for acoustic transversely isotropic media with a vertical axis of symmetry

In multi-parameter ray-based anisotropic migration/inversion, it is essential that we have an understanding of the scattering mechanism corresponding to parameter perturbations. Because the complex nonlinearity in the anisotropic inversion problem is intractable, the construction of true-amplitude linearized migration/inversion procedures is needed and important. By using the acoustic medium assumption for transversely isotropic media with a vertical axis of symmetry and representing the anisotropy with P-wave normal moveout velocity, Thomsen parameter δ and anelliptic parameter η, we formalize the linearized inverse scattering problem for three-dimensional pseudo-acoustic equations. Deploying the single-scattering approximation and an elliptically anisotropic background introduces a new linear integral operator that connects the discontinuous perturbation parameters with the multi-shot/multi-offset P-wave scattered data. We further apply the high-frequency asymptotic Green's function and its derivatives to the integral operator, and then the scattering pattern of each perturbation parameter can be explicitly presented. By naturally establishing a connection to generalized Radon transform, the pseudo-inverse of the integral operator can be solved by the generalized Radon transform inversion. In consideration of the structure of this pseudo-inverse operator, the computational implementation is done pointwise by shooting a fan of rays from the target imaging area towards the acquisition system. Results from two-dimensional numerical tests show amplitude-preserving images with high quality.     

基于桩间土滑动特性的合理桩间距研究

为研究抗滑桩合理桩间距以及荷载传递机制,首先以桩侧摩阻力为拱脚时的破裂面推导出以桩身为拱脚时的破裂角计算公式;然后引入对数螺旋线法确定桩间土体的滑移深度,以土拱效应为基础建立计算模型,求解考虑桩间土体滑移深度的合理桩间距表达式;最后对桩间净距的主要影响因素进行分析,包括滑坡推力、黏聚力、桩截面宽度以及高度。研究结果表明：由桩身和桩侧摩阻力同时作为土拱拱脚更符合实际受力状态,同时求得的土拱拱圈厚度和矢高小于以桩身为拱脚条件下相应值而大于以桩侧摩阻力为拱脚条件下的相应值,并且随桩埋深的增加而增大。     

SH波水平入射穿越垂直断层隧道动力响应分析

结合黏弹性人工边界的时域波动输入方法和显式有限元法,设计了含垂直断层三维场地的SH波输入方法。基于建立的输入方法,研究了垂直断层对隧道地震响应的影响,并通过自由场算例验证了该方法具有较好精度。数值模拟结果表明:对于断层迎波侧的隧道结构,断层会对其地震动响应产生显著的放大作用,对于断层逆波侧的隧道结构,断层会对其产生隔离地震动的作用;相对周围围岩,断层介质的剪切波速越小,其产生的放大效应和隔震效果也会越显著;断层宽度越小,其对隧道地震动响应的影响范围也就越小,但是断层宽度的变化对于断层两侧隧道的地震动响应的影响并不明显。     

南极格罗夫山陨石岩石学特征Ⅰ:非平衡L3型普通球粒陨石

我国第16次南极科学考察队在格罗夫山区域的蓝冰表面回收到28块陨石,其中有6块属于非平衡型(即3型)普通球粒陨石。它们保存了原始的岩石矿物学特征,包括非常清晰的球粒结构、基质未重结晶和不透明、橄榄石和低钙辉石颗粒具有明显的成分环带和极不均一的化学组成等。Fe-Ni合金含量、含Fe总量和橄榄石成分综合分析表明这6块陨石全部属于低铁群(L)。因为非平衡普通球粒陨石橄榄石成分变化的PMD(Fa)值与岩石类型亚型有良好的相关性,因此,根据橄榄石Fa的PMD标准这6块陨石被划分为如下亚型:GRV 99019为3.6型,GRV99020、GRV 99021和GRV 99026为3.5型,GRV 99001为3.4型,GRV 99022为3.0—3.4型。