Spatial Distribution of Contourites in Global Ocean and Its Paleoclimatic Significance—The Contribution of International Ocean Drilling to the Studies of Contourites

Contourite is one of the most important type of sediments in the global ocean, which has recorded significant information on paleoclimatic changes. It is also of great importance for ocean engineering and marine hydrocarbon exploration. The development of scientific ocean drilling, especially the “Integrated Ocean Drilling Program” and the undergoing “International Ocean Discovery Program”, has made great contribution in mapping the spatial distribution of contourites and revealing contourite-related paleoclimatic information, through coring and geophysical exploration in the global ocean. It is found that the global distribution of contourites is controlled predominantly by the global deep-water circulation while its distribution in a specific region can be affected by the intensity of deep currents, tectonic activities, sediment supply, and so on. The geological changes in the global deep-water circulation is, however, further affected by tectonic activities, origins of water masses, as well as climate changes, e.g. the Cenozoic global cooling, changes in the size of the northern hemisphere ice caps, and intensity of monsoon. The main controlling factors of deep water circulation vary with different regions.     

A painting type of flexible piezoelectric device for ocean energy harvesting

Energy harvesting using piezoelectric materials can be realised by periodic external force. Piezoelectric material directly converts strain energy into electric power to capture a wasted ambient kinetic energy. This recovered energy can be used for operating wireless sensors, such as those found in environmental monitoring, mechanical sensing and structural diagnostic. In our previous work, a flexible piezoelectric device, FPED, was proposed and developed as an energy harvester for generating electric power from flow-induced vibration in ocean and wind environments. In this study a FPED with a painted piezoelectric layer, highly durable in order to withstand extreme bending and weathering caused by waves and currents, is proposed and developed by spray coating for use as an ocean energy harvester. A numerical method is developed to predict electro-fluid–structure interactions and to evaluate electrical performance and mechanical behaviours of the painted FPED. Additionally, validation of the numerical model is provided through several experimental tests. This study also investigates the relationship between the stiffness of the painted FPED and the vibrated frequency, as well as determining their influence on the electrical performance. Finally, the outcomes from a field test, conducted in real ocean space, is presented to provide information on electrical performance, mechanical behaviours and durability of painted FPEDs. The paper shows that a painted FPED is a useful and robust energy harvester for generating electric power from harsh environments.     

Oceanographic influences on the distribution and relative abundance of market squid paralarvae (Doryteuthis opalescens) off the Southern and Central California coast

Market squid (Doryteuthis opalescens) are ecologically and economically important to the California Current Ecosystem, but populations undergo dramatic fluctuations that greatly affect food web dynamics and fishing communities. These population fluctuations are broadly attributed to 5–7‐years trends that can affect the oceanography across 1,000 km areas; however, monthly patterns over kilometer scales remain elusive. To investigate the population dynamics of market squid, we analysed the density and distribution of paralarvae in coastal waters from San Diego to Half Moon Bay, California, from 2011 to 2016. Warming local ocean conditions and a strong El Niño event drove a dramatic decline in relative paralarval abundance during the study period. Paralarval abundance was high during cool and productive La Niña conditions from 2011 to 2013, and extraordinarily low during warm and eutrophic El Niño conditions from 2015 to 2016 over the traditional spawning grounds in Southern and Central California. Market squid spawned earlier in the season and shifted northward during the transition from cool to warm ocean conditions. We used a general additive model to assess the variability in paralarval density and found that sea surface temperature (SST), zooplankton displacement volume, the log of surface chlorophyll‐a, and spatial and temporal predictor variables explained >40% of the deviance (adjusted r² of .29). Greatest paralarval densities were associated with cool SST, moderate zooplankton concentrations and low chlorophyll‐a concentrations. In this paper we explore yearly and monthly trends in nearshore spawning for an economically important squid species and identify the major environmental influences that control their population variability.     

Structural styles of Albian rafts in the Espírito Santo Basin (SE Brazil): Evidence for late raft compartmentalisation on a ‘passive’ continental margin

In recent years, hydrocarbon exploration offshore SE Brazil has been focusing on Lower Cretaceous strata deformed by gravity gliding above Aptian salt. A three-dimensional (3D) seismic volume from the Espírito Santo Basin, SE Brazil is here used to: a) test the parameters considered to control raft tectonics on a margin tectonically reactivated in the Cenozoic, and b) investigate the impact of prolonged halokinesis on raft deformation. Offshore Espírito Santo, the combined effects of halokinesis and multiple (Andean) tectonic phases are expressed by local collapse, fault reactivation and late segmentation of Albian rafts. As a result of this deformation we observe four main raft geometries: a) rolled-over rafts, b) tabular rafts, c) collapsed rafts, and d) folded and tilted rafts on the flanks of salt rollers. This work shows that salt rollers formed buttresses to moving Albian-Cenomanian rafts, with withdrawal of salt from underneath some of the rafts leading to their collapse and welding onto pre-salt strata. This process occurred in the studied part of the Espírito Santo Basin with minimum control of post-raft overburden thickness on raft compartmentalisation. Salt withdrawal from underneath the rafts is an important phenomenon as it enhanced connectivity between pre-salt and post-salt units, potentially promoting the migration of hydrocarbons from syn-rift source units into post-salt reservoirs.     

Transport and transformation of surface water masses across the Mascarene Plateau during the Northeast Monsoon season

The Mascarene Plateau lies in the south-west Indian Ocean between the islands of Mauritius and the Seychelles Bank, and is characterised by a series of shallow banks separated by deep (>1 000 m), narrow channels. The plateau acts as an obstruction to the general ocean circulation in this region, separating the westward-flowing South Equatorial Current (SEC) into two branches downstream of the plateau. In this article, we present the results of a survey conducted along the entire Mascarene Plateau during the Northeast Monsoon, in October–November 2008. In addition, data from Argo floats were used to determine the origin of water masses entering this region. The plateau contains three gaps through which branches of the SEC are channelled. The northern, central and southern gaps receive 14.93 Sv, 14.41 Sv and 6.19 Sv, respectively. Although there are differences in water-mass properties to the west and east of the Mascarene Plateau due to mixing, the SEC acts as a sharp boundary between water masses of southern and northern Indian Ocean origin. Mixing occurs in the central gap between intermediate water masses (Red Sea Water [RSW] and Antarctic Intermediate Water [AAIW]) as well as in the upper waters (Subtropical Surface Water [STSW] and Indonesian Throughflow Water [ITW]). Through the northern gap, mixing occurs between Arabian Sea High-Salinity Water (ASHSW), ITW and Tropical Surface Water (TSW), while through the southern gap, mixing occurs between STSW and ITW. North Indian Deep Water (NIDW) is present in the region but the plateau appears to have no effect on it.     

基于地学知识的大尺度土地利用/土地覆盖精细化分类方法研究

人类活动对生态环境具有显著影响,大尺度土地利用/覆盖变化（Land Use/Cover Change,LUCC）作为人类活动最直接的表征,能够很好地反映这一过程,因此进行精确而迅速的大尺度土地利用/覆盖分类与提取方法研究尤为关键。全球覆盖产品GlobCover（2005/2006）数据已经具有良好的空间精度和数据准确度,但仍然存在一些分类误差。为提高地表覆被分类精度,本文以GlobCover（2005/2006）的巴西数据为例,以2005年Landsat TM/ETM影像为主要信息源,结合相应地学知识与辅助数据,利用人机交互逐栅格修改方法得到2005年土地利用数据产品。结果表明：通过对GlobCover数据和本次成果数据进行精度评价与对比分析,GlobCover数据巴西地区的总体精度为67.17%,Kappa系数为0.58,改进后产品总体精度为93.39%,Kappa系数为0.91。此外,改进后数据显示巴西常绿阔叶林面积最大,面积比例达45.67%;农地/自然植被镶嵌面积次之,比例为19.19%;封闭灌丛面积最小,比例为12.34%。农地/自然植被镶嵌和灌丛与草地2种地类的修改比例最大,其中混合像元地类比例减少3.54%,灌丛与草地比例增加3.81%。综上,改进方法可以有效地提高土地利用/覆盖分类的效率和精度,为后续大尺度LUCC产品的制作和以LUCC产品为基础的相关研究提供参考。     

东海环流的一个两层模式

本文用一个两层原始方程数值模式，对东海的环流现象进行了机制性的探讨。从整体上来看，海区的一些主要流态特征彼此密切相关，且在动力上都是比较稳定的。黑潮在台湾东北的入侵主要表现在下层。底斜联合效应（ＪＥＢＡＲ）、惯性效应、摩擦效应都是这支入侵流态的发生机制，而底形与行星β效应则使它表现出向岛强化的特征。下层黑潮入侵后，大部分作反气旋回转，成为台湾暖流（ＴＷＣ）下层的外海分支。ＴＷＣ下层沿岸分支能否形成，则取决于黑潮入流上下流速比γ的大小，以及上层海峡入流是否北上。ＴＷＣ上层流动的形成是海峡水入侵后在β效应作用下的结果，它在温州外海也将分出一支向外海流去。文章指出，台湾东北的冷水块不是“尾涡”所致，而是下层黑潮舌状入侵的具体表征；台湾北部的暖涡则是上层ＴＷＣ北上时与冷水块相互作用的结果。此外，本文对钓鱼岛以北的锋涡与逆流现象也作了一些初步的分析与讨论。     

Spillover effect offsets the conservation effort in the Amazon

Diverse conservation efforts have been expanding around the globe, even under the stress of increasing agricultural production. A striking example is the supply-chain agreements put upon the Amazon forest which had reduced deforestation by 80% from the early 2000s (27,772 km²) to 2015 (6207 km²). However, evaluation of these conservation efforts usually focused on the impacts within the Amazon biome only, while the effects that spill over to other areas (e.g., displacement of environmental pressure from one area to another) were rarely considered. Ignoring spillover effects may lead to biased or even wrong conclusions about the effectiveness of these conservation efforts because the hidden cost outside the target area of conservation may offset the achievement within it. It is thus important to assess the spillover effects of these supply-chain agreements. In this study, we used the two supply-chain agreements (i.e., Soy Moratorium and zero-deforestation beef agreement) implemented in the Amazon biome as examples and evaluated their spillover effects to the Cerrado. To achieve a holistic evaluation of the spillover effects, we adopted the telecoupling framework in our analysis. The application of the telecoupling framework includes the interactions between distant systems and extends the analytical boundaries beyond the signatory areas, which fill the gap of previous studies. Our results indicate that the supply-chain agreements have significantly reduced deforestation by half compared to projections within the sending system (i.e., Pará State in the Amazon, which exports soybeans and other agricultural products), but at the cost of increasing deforestation in the spillover system (i.e., a 6.6 time increase in Tocantins State of the Cerrado, where deforestation was affected by interactions between the Amazon and other places). Our study emphasizes that spillover effects should be considered in the evaluation and planning of conservation efforts, for which the telecoupling framework works as a useful tool to do that systematically.     

Variation of the North Equatorial Current,Mindanao Current,and Kuroshio Current in a High-Resolution Data Assimilation during 2008–2012

Outputs from a high-resolution data assimilation system,the global Hybrid Coordinate Ocean Model and Navy Coupled Ocean Data Assimilation （HYCOM＋NCODA） 1/12° analysis,were analyzed for the period September 2008 to February 2012.The objectives were to evaluate the performance of the system in simulating ocean circulation in the tropical northwestern Pacific and to examine the seasonal to interannual variations of the western boundary currents.The HYCOM assimilation compares well with altimetry observations and mooring current measurements.The mean structures and standard deviations of velocities of the North Equatorial Current （NEC）,Mindanao Current （MC） and Kuroshio Current （KC） also compare well with previous observations.Seasonal to interannual variations of the NEC transport volume are closely correlated with the MC transport volume,instead of that of the KC.The NEC and MC transport volumes mainly show well-defined annual cycles,with their maxima in spring and minima in fall,and are closely related to the circulation changes in the Mindanao Dome （MD） region.In seasons of transport maxima,the MD region experiences negative SSH anomalies and a cyclonic gyre anomaly,and in seasons of transport minima the situation is reversed.The sea surface NEC bifurcation latitude （NBL） in the HYCOM assimilation also agrees well with altimetry observations.In 2009,the NBL shows an annual cycle similar to previous studies,reaching its southernmost position in summer and its northernmost position in winter.In 2010 and 2011,the NBL variations are dominantly influenced by La Ni（n）a events.The dynamics responsible for the seasonal to interannual variations of the NEC-MC-KC current system are also discussed.     

宁夏银川湿地现状及保护对策

在对银川市湿地资源调查的基础上,分析了银川市湿地面积、类型、区域分布特点,总结了湿地保护管理的现状和存在的问题,提出了湿地保护管理的措施和对策,为银川市湿地保护管理和合理利用提供参考。