基于多期遥感影像的砂质岸线提取方法——以海阳沙滩为例

文章提出一种基于发展多期影像和归一化水体指数(NDWI)的砂质岸线自动提取方法,以山东半岛海阳沙滩为实验区,应用2005年多个月份的7景Landsat 5TM遥感影像为数据源,提取实验区砂质岸线。利用908专项修测岸线对提取的海岸线进行精度检验。结果表明,岸线偏差距离为20.9m、均方根误差(RMSE)为33.6m。该方法可为砂质岸线的提取与变迁分析研究提供参考依据。     

厦门海岸线遥感动态监测研究

海岸线是指多年大潮高潮位时的海陆界线。不同类型海岸有各自的地貌特征,它们在遥感影像上的解译标志与提取方法也存在差异。目前大部分海岸线自动提取研究只是解译出遥感影像中的水边线,即卫星在过顶时刻所记录的海水与陆地的瞬时交界线,并不是真正意义上的海岸线。本文以厦门地区海岸影像为研究对象,根据不同海岸类型的地貌特点采用不同的海岸线解译方法,提取出1987年、1997年和2007年的海岸线,并进行岸线变迁原因分析。实践表明：人工海岸、基岩海岸、砂质海岸及红土海岸的海岸线解译标志明显,提取效果较好,基本能够实现计算机自动提取;淤泥质海岸在遥感图像上呈现复杂的边缘,仍没有理想的线性特征自动提取技术,是海岸线提取中的难点。     

基于机载LiDAR与潮汐推算的海岸带自然岸线遥感提取方法研究

海岸线对于海岸带保护与管理具有重要意义。海岸线现场测绘施测周期长且在地形复杂的区域施测难度大,基于遥感影像的海岸线判绘对解译人员的要求高,难以获取严格意义的海岸线。针对上述问题,本文提出一种基于机载LiDAR与潮汐推算的自然岸线遥感提取方法:基于机载LiDAR系统获取的航空正射影像解译瞬时水边线,应用LiDAR系统提取的DEM和建立的高程系统转换模型,通过潮汐数据推算研究区域的海岸线。通过与“908专项”航空遥感调查岸线结果比对,按本文方法所提取的3种自然岸线(砂质岸线、基岩岸线和淤泥质岸线)的均方根误差分别为1.66,5.23和32.48 m。结果表明,该方法可用于砂质岸线和基岩岸线的提取,且具有无需开展现场测量工作的优势,可提高海岸线提取的效率。     

基于边缘引导约束的高分辨率遥感影像海岸线提取

针对海岸线的影像特征,提出一种基于边缘引导约束的海岸线提取方法。该方法是在遥感影像进行中值滤波处理,去除噪声的基础上,通过交互方式对遥感影像进行灰度拉伸,以增强海岸线特征;再利用梯度算子卷积运算得到梯度影像;然后通过边缘像素点和灰度差阈值引导种子点进行生长,进而提取包括滩涂在内的水域或其他地物;最后通过轮廓跟踪提取生长区域的边界,即海岸线。试验表明,该方法可准确提取出海岸线位置,效果较好。     

高分影像砂质海岸线精细提取及校正方法

通过遥感影像稳定获取大范围、连续性海岸线数据,是开展海岸带研究的重要手段之一.针对传统边缘检测算法处理高分辨率遥感影像存在的噪声敏感性、阈值不稳定性等问题,引入一种强鲁棒性的结构森林边缘检测(Strected?Forests?Edge?Detection,?SE)算法,对海口市西海岸砂质岸线进行识别,并提出基于Bruu...     

基于多光谱数据的黄河三角洲岸线自动提取

基于多光谱数据对海岸线自动提取的问题研究已久。针对国内外岸线提取方法较为单一的现状,提出兼顾光谱特征与空间关系的海岸线自动提取方法:将2014年黄河三角洲Landsat8-OLI影像与实测地物反射率光谱对比,选择敏感波段建立提取模型,之后对研究岸段进行分类并自动提取,同时基于908专项山东省修测海岸线标准的目视解译方法对实验部分的海岸线进行提取,最后通过ROC曲线原则对提取结果分别进行0.5与1像元精度评价,实验证明该方法在1个像元精度(提取置信度均高于90%)范围内能快速、准确地提取黄河三角洲复杂地貌类型地区的海岸线,所得到的矢量岸线可直接用于地理信息系统(GIS)分析。     

基于遥感影像提取山东半岛复杂海岸线及海岸线多年变迁研究

海岸线变迁的研究有助于对海岸带保护和可持续发展提供科学依据.本文针对山东半岛复杂的海岸线类型,选取1984-2018年的6期Landsat系列遥感影像,采用改进的归一化差异水体指数(Modified NDWI)和边缘检测算法(Canny)对图像进行阈值分割实现海陆分离,使用面向对象法提取了山东半岛海岸线,并结合高分影像...     

基于天绘一号卫星多光谱影像的海岸线自动提取方法

针对常规人工海岸线测量方法耗费人力物力、效率低、工作环境相对危险,难以快速反映海岸线动态变化的问题,提出一种基于天绘一号卫星多光谱影像的海岸线自动提取与分类方法。所提方法首先结合NDWI指数和水平集模型实现全自动水边线提取,然后采用面向对象分割技术和空间拓扑关系提取临海地物基元,最后结合遥感影像海岸线解译标志建立决策树完成临海基元的分类与海岸线提取。实验表明,海岸线提取结果能够作为1∶2.5万海图测制与更新的参考数据。     

海岸水边线提取方法在GF-2卫星影像中的适应性研究

准确提取海岸水边线是海岸线变迁研究中必不可少的基本工作。本文以海南省陵水黎族自治县2016年的GF-2影像为数据源,在大气校正和正射校正等预处理的基础上,结合数学形态学处理等方法,采用NDWI (Normalized Difference Water Index)阈值法、ISOADTA (Iterative Self-Organizing Data Analysis Technique Algorithm)、SVM (Support Vector Machine)和面向对象法（Object-Oriented Classification,OOC）等4种不同方法来对海岸水边线进行提取,并对其提取结果进行定性和定量评估,进而分析比较了这4种方法在提取人工海岸、砂质海岸和基岩海岸等3种不同海岸类型的水边线时的提取效果和提取精度。结果表明,SVM方法在3种海岸水边线上的总体提取效果最好,总体提取精度最高。     

GF-3号SAR卫星遥感围填海监测方法研究——以大连金州湾为例

依据不同围填海类型在高分三号(GF-3)合成孔径雷达(synthetic aperture radar,SAR)卫星遥感影像上可分性,建立围填海遥感分类体系及相应的围填海类型解译标志,进而分析SAR图像岸线提取方法,构建GF-3围填海监测技术流程。采用几何主动轮廓模型进行GF-3 SAR影像自动提取海岸线,获得围填海专题图。通过外业精度调查验证GF-3 SAR卫星遥感影像可以有效获取围填海信息。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.