划分变性水团边界的温盐点聚对照法与东海西部海区变性水团的分析     

苏育嵩 《中国海洋大学学报(自然科学版)》1989,(Z1)

温盐点聚对照法是根据温盐点聚图而确定变性水团边界的一种分析方法。用这种方法分析东海西部海区中的变性水团,可以得到如下结果:在该海区中除四个原型水团之外,还有两个变性水团。具有区域性特征的变性回归线,仅在寒冷季节存在。可以看出,变性交换区与顺时针环流的存在密切相关。提出了检验该海区各变性水团消长变化的模式。最后,描述了混合带与中心渔场位置之间的关系。  相似文献   

Small turbidite systems in a complex tectonic setting (SW Mediterranean Sea): morphology and growth patterns   总被引：1，自引：0，他引：1  

Beln Alonso  Gemma Ercilla 《Marine and Petroleum Geology》2002,19(10)

Three small turbidite systems (Almeria, Sacratif, and Guadiaro), each tens of kilometres long, are developed in the complex morpho-structural setting of the northern Alboran Sea and have similar primary architectural elements (canyons, channel-levee systems, lobes). However, comparison reveals differences in the axial gradients of their canyons, depth/physiographic location, morphological framework, and lateral and longitudinal sedimentary shifts of turbidite deposition. The depositional architecture and sedimentary evolution from late Pliocene to Quaternary seems to be conditioned by number of submarine feeding sources (canyons), sea-level fluctuations and local tectonic (e.g. margin/canyon-channel gradients, faults). We group the Alboran turbidite systems into two models: mud/sand-rich submarine point-source and mud/sand-rich multiple submarine source ramp.  相似文献   

南海中北部海域晚更新世以来沉积速率及其变化机制     

许志峰 《台湾海峡》1995,14(4):356-360

本文根据沉积速率变化受沉积环境制约机理，计算了南海中北部海域晚更新世以来沉积速率的变化，分析该海域沉积环境的特征。通过７个粒状样沉积速率的计算与分析，认为晚更新世以来沉积速率明显高于典型的大洋沉积环境的沉积速率，平均为１０．２ｃｍ／ｋａ，北部海域平均沉积速率为１１．３ｃｍ／ｋａ，南部海域平均沉积速率为６．０ｃｍ／ｋａ，表现为近陆区沉积速率高，远离大陆速率低的特点。  相似文献   

Deep Seabed Mining: Past Failures and Future Prospects   总被引：8，自引：0，他引：8  

G. P. Glasby 《Marine Georesources & Geotechnology》2002,20(2):161-176

The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U.N. Convention on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining. Attention then focused on Co-rich manganese crusts from seamounts. Since the mid-1980s, a number of new players have committed themselves to long-term programs to establish the viability of mining deep-sea manganese nodules. These programs require heavy subsidy by the host governments. Au-rich submarine hydrothermal deposits located at convergent plate margins are now emerging as a more promising prospect for mining than deep-sea manganese deposits.  相似文献   

大气对外强迫低频遥响应的数值模拟 Ⅰ:对赤道东太平洋SSTA的响应   总被引：3，自引：0，他引：3  

肖子牛  李崇银 《大气科学》1992,(6)

本文通过在IAP-GCM上实现的数值模拟,研究了大气对赤道东太平洋地区暖SSTA的响应,着重讨论了大气遥响应的性质和演变过程. 数值模拟清楚地表明,大气对异常外源的响应主要是一种具有30—60天周期的低频遥响应.分析不同地区和不同季节这种强迫响应的30—60天低频振荡的结构及活动,可以清楚看到它与大气中实际存在着的30—60天振荡极为相似.因此也可以认为,大气对海温异常的强迫遥响应是激发产生全球大气30—60天振荡的重要机制.  相似文献   

云开地区燕山期岩浆活动与金银矿化关系   总被引：1，自引：0，他引：1  

甘志邦 《矿产与地质》1992,6(5):380-386

通过对广西云开地区岩浆活动与金银矿化关系的研究表明,金银矿主要是燕山期岩浆作用形成的;矿化岩体与金银矿化在空间位置上存在“东向性”和“定距性”规律;岩浆岩岩石化学成分、岩浆分异程度、成因类型的不同,导致了金银成矿的显著差异;燕山期岩浆活动对金银成矿,既提供了成矿热液,也提供了主要的物质来源。  相似文献   

A Multiple Criteria Decision Modelling approach to selection of estimation techniques for fitting extreme floods     

L. Duckstein  B. Bobée  F. Ashkar 《Stochastic Hydrology and Hydraulics》1991,5(3):227-238

The problem of fitting a probability distribution, here log-Pearson Type III distribution, to extreme floods is considered from the point of view of two numerical and three non-numerical criteria. The six techniques of fitting considered include classical techniques (maximum likelihood, moments of logarithms of flows) and new methods such as mixed moments and the generalized method of moments developed by two of the co-authors. The latter method consists of fitting the distribution using moments of different order, in particular the SAM method (Sundry Averages Method) uses the moments of order 0 (geometric mean), 1 (arithmetic mean), –1 (harmonic mean) and leads to a smaller variance of the parameters. The criteria used to select the method of parameter estimation are:

–	- the two statistical criteria of mean square error and bias;
–	- the two computational criteria of program availability and ease of use;
–	- the user-related criterion of acceptability.

These criteria are transformed into value functions or fuzzy set membership functions and then three Multiple Criteria Decision Modelling (MCDM) techniques, namely, composite programming, ELECTRE, and MCQA, are applied to rank the estimation techniques.  相似文献   

资源三号01星GPS天线相位中心变化在轨估计及对精密定轨的影响     

袁俊军  赵春梅 《大地测量与地球动力学》2018,38(10):1043-1047

利用资源三号01星（ZY3-01）实测GPS数据，基于简化动力学定轨方法和残差法估计该星GPS天线的在轨相位中心变化（phase center variation，PCV）模型，并分析该星PCV对精密定轨的影响。实验表明，通过考虑PCV模型，ZY3-01星定轨结果在重叠弧段对比上，三维位置RMS值有4.5 mm的精度提升，SLR检核RMS值有1.2 mm的精度提升，且各SLR测站检核结果也均有不同程度的精度提升。  相似文献   

A Kinematical Calibration of the Galactocentric Distance     

Ming Shen  Zi Zhu Department of Astronomy  Nanjing University  Nanjing   《中国天文和天体物理学报》2007,7(1):120-128

1 INTRODUCTION The distance to the Galactic center R0 is a fundamental constant for astronomy and astrophysics. Most determinations of astronomical quantities are directly connected with the Galactic distance scale, e.g., the rotational speed of our Galax…  相似文献   

Search for radio pulsations in four anomalous X-ray pulsars and discovery of two new pulsars     

Marta Burgay  Nanda Rea  GianLuca Israel  Andrea Possenti  Luciano Burderi  Tiziana Di Salvo  Nichi D’Amico  Luigi Stella  Elisa Nichelli 《Astrophysics and Space Science》2007,308(1-4):531-534

We have performed deep searches for radio pulsations from four southern anomalous X-ray pulsars (AXPs) to investigate their physical nature in comparison with the rotation powered pulsars. The data were acquired using the Parkes radio telescope with the 1.4 GHz multibeam receiver. No pulsed emission with periodicity matching the X-ray ephemeris have been found in the observed targets down to a limit of ∼0.1 mJy. A blind search has also been performed on all the 13 beams of the multibeam receiver (the central beam being pointed on the target AXP), leading to the serendipitous discovery of two new radio pulsars and to the further detection of 18 pulsars. Also a search for single dispersed pulses has been performed in the aim to detect signals similar to those of the recently discovered rotating radio transients.   相似文献