北极海冰密集度数值预报及验证评估研究

本文系统地评估了国家海洋环境预报中心于我国第七次北极科学考察期间开展的北极海冰密集度数值预报结果。该预报系统基于麻省理工大学通用环流模式，并采用牛顿松弛逼近（Nudging）资料同化方法，计算输出未来1~5 d的北极海冰密集度预报产品。本文将数值预报结果同卫星观测的海冰密集度、再分析资料和"雪龙"号第七次北极考察期间观测的海冰密集度数据进行了对比分析。结果表明，预报的北极海冰密集度小于卫星观测值，24 h、72 h和120 h预报结果的偏差分别为-2.7%、-3.1%和-3.2%；数值产品的预报技巧好于气候态结果和惯性预报，但是在海冰出现快速融化或冻结时，基于Nudging同化的数值预报技巧仍有不足。另外，相比船测数据，数值预报结果在海冰边缘区的偏差相对较大，24 h、72 h和120 h预报结果的偏差分别为8.8%、12.0%和14.5%。     

极地科学考察中海冰监测和预报的研究应用

本文简单介绍了国家海洋环境预报中心在极地海冰监测和预报研究应用领域开展工作的背景、内容和成果.从卫星遥感监测海冰的方法;卫星接收和图像处理方法;卫星微波资料的处理方法;海冰变化规律及其长期变化的理论方法和长期实时预报的方法四个方面进行了阐述,并叙述了今后工作的方向.     

2005～2006年冬季渤海海冰数值预报

本文概述2005-2006年冬季渤海冰情。介绍该冬季业务化海冰数值预报工作和应用PIC模式开展海冰数值后报试验,其业务化海冰数值预报的客观检验结果满足业务预报精度指标。     

南极中山站海冰综合观测系统的建设

利用我国南极中山站的越冬观测平台,国家海洋环境预报中心自2010年起,在中山站附近海域选取固定海冰观测点,陆续布放各种自动化观测设备,初步建立海冰综合观测系统,开展常规气象要素、辐射、涡动通量、积雪和海冰温度、厚度、海水温盐等多要素的业务化观测。目前每年度的现场观测始于南半球初冬,即3—4月份,持续时间一般为8—10个月,自动观测要素的采样频率一般为1 min,人工观测要素的采样频率一般为7 d。结果表明:获取的高精度、长时间序列的现场数据可以广泛应用于我国的南极海冰数值预报和雪龙船海冰服务保障等工作中,初步解决了极地海冰预报保障对现场海冰观测数据的迫切需求。     

黄,渤海海冰预报

一、前 言 随着海上交通运输、海洋工程及海上石油开发事业的迅速发展,海冰的生消对海上作业带来了一定的危害;尤其在冰情特别严重的年份（1969年）曾发生了历史上罕见的特大冰封以来,为了保证国家财产和人民生命的安全,继而开展了海冰预报服务业务。目前我国海冰预报所使用的方法,主要以经验物理及数理统计预报方法为主,海冰数值预报方法正在进行研究。前两类预报方法,应用于海冰预报工作,已为国民经济服务取得了一定的效果。     

“海洋1号”卫星在海冰监测和预报中的应用

“海洋1号A”卫星是我国发射的第一颗海洋卫星.2002~2003年冬季,该卫星首次应用于我国渤海海冰监测和预报.建立了从卫星1B级数据开始的海冰反演系统,提供海冰遥感图像和海冰密集度、冰厚与冰外缘线数值产品,作为渤海海冰监测和海冰数值预报初始场的重要信息来源,以及海冰预报质量检验的参考依据之一.介绍所发展的“海洋1号A”卫星海冰反演系统的流程、算法和反演参数,海冰反演结果,及其在渤海海冰监测和预报中的应用.     

2002～2003渤海海冰数值预报

海冰数值预报是海冰业务预报的主要方法之一。国家海洋环境预报中心建立了业务化的渤海海冰数值预报系统，并进行了多年的业务化运行。随着我国卫星遥感事业和数值天气预报技术的发展，海冰预报系统也在不断发展中。本文介绍了2002～2003冬季应用HY—1卫星海冰遥感和T213数值天气预报模式产品对该海冰数值预报系统的改进，对2002～2003冬季海冰数值预报的结果进行了分析和比较。     

海冰密集度卫星遥感反演研究进展

海冰密集度是海冰的重要参数之一,在冰区导航、海上作业、海冰模式验证和气候模型改进等方面具有重要意义。卫星遥感具有覆盖范围广、重访周期短、成本相对低等优势,已成为获取海冰密集度的主要观测手段。本文从主被动微波遥感和光学遥感的角度,回顾了现阶段海冰密集度卫星遥感反演研究进展情况,包括海冰监测传感器、海冰密集度反演算法和海冰密集度产品等。结果表明,被动微波遥感是目前获取海冰密集度的主要方式,已发展出许多成熟的业务化算法;主动微波遥感数据已成为制作冰情图的主要数据源,海冰密集度反演算法由合成孔径雷达SAR（Synthetic Aperture Radar）图像分类向深度学习算法发展;光学遥感海冰密集度算法较为成熟,但受限于云层和夜晚限制,其反演结果多用于其他海冰密集度产品的验证。受传感器硬件限制,3种观测手段各有其长处与不足。为获得高精度、高时空分辨率的海冰密集度数据,开展多源数据融合研究是解决传感器性能瓶颈的有效手段。大数据时代,基于深度学习的海冰密集度卫星遥感反演技术快速发展,需要深度融入海冰密集度卫星遥感领域知识。海冰密集度卫星遥感反演应着力于海冰预报服务,致力于提高我国的海冰预报能力。     

海冰数值预报方法研究通过鉴定和验收

国家海洋环境预报中心承担的“七五”科技攻关项目──“76-02-07”海冰数值预报方法研究取得突破性进展,顺利通过专家鉴定和国家验收。 海冰是我国重要的灾害性海况之一,在我国渤海北部,历史上曾出现过严重的海上冰封,致使平台被冰推翻,拉筋被割断,既使素有不冻港之称的秦皇岛由于冰封长达月余之久,从天津港口进出的一百多艘货船被冰阻挡无法航行,经济损失惊人。由此可见,随着海事活动的日益频繁,海冰已成为海上生产作业和航行不可轻视的天敌。从1958年开始,用30多年的时间、逐步建了立适合我国国情的海冰观测,调查和预报系统,但这种经验加统计的定性趋势预报方法,远不适应当前经济建设的发展,给海上施工、生产、交通、航运带来严重的影响。1986年以吴辉碇副教授为首的海冰专题科技攻关研究组,克服海冰观测资料奇缺,预报系统不健全的种种困难,经过5年的艰苦攻关,以我国海冰前期预报和科研为基础,博国际数十年海冰预报和研究之经验,采美国、芬兰、瑞典和苏联等国的先进的海冰模式,结合渤海的气候,水文和冰情特点,就海冰的生、消、增长漂移及海冰本身的许多物理特性作了大量理论和数值试验,合理地考虑海冰动力-热力特性、海冰大气、海冰与海洋的相互作用,采用塑性-粘性结构原理计算冰内力。推出了适     

MODIS渤海海冰遥感资料反演

鉴于渤海海冰监测和预报对海冰卫星遥感数字化产品的迫切需求,本文利用MODIS的1B级数据进行渤海海冰参数反演,提供海冰遥感图像和海冰密集度、冰厚数值产品,作为渤海海冰监测和海冰数值预报初始场的重要信息来源,以及海冰预报质量检验的参考依据之一。反演结果表明,其各通道对海冰性质有很好的反映,资料信号比较稳定,对不同密集度和厚度的冰有较好的区分,相对NOAA/AVHRR和HY-1A资料有更好的实际应用价值;Terra/MODIS和HY-1A/COCTS海冰遥感反演结果对比也为HY-1A系列卫星海冰遥感的改进和提高提供有益的启示。     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.     

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。     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

<正>~~     

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,