共查询到20条相似文献，搜索用时 15 毫秒
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The Localized Weighted Ensemble Kalman Filter(LWEnKF) is a new nonlinear/non-Gaussian data assimilation(DA) method that can effectively alleviate the filter degradation problem faced by particle filtering, and it has great prospects for applications in geophysical models. In terms of operational applications, along-track sea surface height(AT-SSH), swath sea surface temperature(S-SST) and in-situ temperature and salinity(T/S) profiles are assimilated using the LWEnKF in the northern South China ... 相似文献
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日本新任首相安倍晋三于2006年10月8日访华。他就任后第一次出访就到中国,说明很重视与中国和亚洲的外交关系,旨在改变小泉时代留下的政治后遗症——中日关系冷淡,日本亚洲外交危机。安倍访华期间中日发表联合公报,其内容包括坚持东海磋商,加快共同开发步伐,寻求双方都能接受的方案等。安倍访华标志着中日紧张关系开始缓和,但并不等于中日东海问题就此迎刃而解。中日东海问题是长期形成的,错综复杂的,不可能通过一两次首脑访问就能解决根本问题,充其量只能起到遏制势头恶化的作用。以笔者之见,在东海问题上日方仍然掌握着主动权,海上保安厅出动武装舰船和飞机始终控制着我国固有领土——钓鱼岛及其周边海域。至今没有任何迹象表明日本政府要收回授权民间企业在东海试开采的成命,强行试钻的可能性依然存在。中日双方虽然就东海共同开发达成继续进行磋商的一致意见,但从发展趋势分析最终仍有利日方。 相似文献
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Bias correction of sea surface temperature retrospective fore-casts in the South China Sea 总被引：2，自引：1，他引：1
Guijun Han Jianfeng Zhou Qi Shao Wei Li Chaoliang Li Xiaobo Wu Lige Cao Haowen Wu Yundong Li Gongfu Zhou 《海洋学报(英文版)》2022,41(2):41-50
Offline bias correction of numerical marine forecast products is an effective post-processing means to improve forecast accuracy. Two offline bias correction methods for sea surface temperature(SST) forecasts have been developed in this study: a backpropagation neural network(BPNN) algorithm, and a hybrid algorithm of empirical orthogonal function(EOF) analysis and BPNN(named EOF-BPNN). The performances of these two methods are validated using bias correction experiments implemented in the South... 相似文献
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夏威夷历史海啸记录包含远距离和当地产生的海啸,由这些事件引起的人员伤亡和对建筑、环境造成的破坏与损失是惊人的,但是在近来才有一些对历史海啸沉积事件的综合性的研究.夏威夷多岩石的海岸线的演变主要是海啸和风暴的贡献,然而区分风暴和海啸是很难的,特别是相关的小的历史海啸事件.因此夏威夷海啸的研究往往关注于大的古海啸沉积事件.研究表明远距离产生的事件,如1946年阿留申海啸对瓦胡岛岩石岸线的演变具有重要影响.活火山也有助于岩石岸线的形成,且容易引发当地海啸.现代活动的Kilauea火山南侧海域的逐步沉降并没有引起太平洋范围内的破坏性的大海啸,但引发了局部一系列重要的海啸事件,这些事件的周期被估计认为是200年. 相似文献
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以印度洋深层海水,用柴油和石油作为混合碳源经富集培养、分离获得一株具有很强的柴油降解能力的茵株P40.茵株P40革兰氏染色阴性,接触酶和氧化酶为阳性,能还原硝酸盐,不能还原亚硝酸盐.16S rDNA Blastn 结果表明其与 Alcanivorax dieselolei B-5T(柴油食烷茵)及 A.dieselolei NO1A具有最高相似性,均为99.8%.茵株P40的gyrB序列与 A.dieselolei NO1A同源性也高达99.2%.而与A.dieselolei B-5T只有86.9%.此外,从茵株P40中克隆到两个烷烃羟化酶alkB基因片断,分别命名为P40-alkB1和P40-alkB2.其中P40-alkBl与报道的 A.dieselolei B-5T 中的 alkB 同源性较高,达96.3%,而与同为深海来源的茵株NO1A的alkB的同源性更是达100%,P40-alkB2则与A.borkumensis SK2T(泊库岛食烷茵)的alkB1同源性最高,但仅为65%. 相似文献
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保障渔民合法权益是深化海洋管理工作面临的重要课题 总被引：2，自引：0，他引：2
舟山是我国唯一以群岛设立的地级市,区域总面积2.22万km2,其中海域面积2万hm2余,“港、景、渔”等海洋资源十分丰富,是名副其实的海洋大市。 相似文献
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YU Yue-min 《中国海洋工程》2021,35(2):301-307
The performance of dual perforated floating plates in a rectangular tank is investigated based on the model tests under different external excitations for different filling rates.It is found that dual perforated floating plates in the tank can remarkably mitigate violent resonant sloshing responses compared with the clean tank,especially when the external excitation frequency is in the vicinity of the first-order resonant frequency.Next,the parametric studies based on different filling rates and external excitation amplitudes are performed for the first-order resonant frequencies.The presence of dual perforated floating plates seldom shifts the sloshing natural frequencies.Further,dual perforated floating plates change the sloshing modes from the standing-wave mode in the clean tank to the Utube mode,which can arise from the sloshing reduction to some extent. 相似文献
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GPU-Based DEM Simulations of Global Ice Resistance on Ship Hull During Navigation in Level Ice 总被引：1，自引：0，他引：1
The ice resistance on a ship hull affects the safety of the hull structure and the ship maneuvering performance in icecovered regions.In this paper,the discrete element method(DEM)is adopted to simulate the interaction between level ice and ship hull.The level ice is modeled with 3D bonded spherical elements considering the buoyancy and drag force of the water.The parallel bonding approach and the de-bonding criterion are adopted to model the freezing and breakage of level ice.The ship hull is constructed with rigid triangle elements.To improve computational efficiency,the GPU-based parallel computational algorithm was developed for the DEM simulations.During the interaction between the ship hull and level ice,the ice cover is broken into small blocks when the interparticle stress approaches the bonding strength.The global ice resistance on the hull is calculated through the contacts between ice elements and hull elements during the navigation process.The influences of the ice thickness and navigation speed on the dynamic ice force are analyzed considering the breakage mechanism of ice cover.The Lindqvist and Riska formulas for the determination of ice resistance on ship hull are employed to validate the DEM simulation.The comparison of results of DEM,Lindqvist,and Riska formula show that the DEM result is between those the Lindqvist formula and Riska formula.Therefore the proposed DEM is an effective approach to determine the ice resistance on the ship hull.This work can be aided in the hull structure design and the navigation operation in ice-covered fields. 相似文献
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以长海县1993年和2005年Landsat-TM数据为基础,运用遥感软件ENVI,经噪音剔除、主成分变换、彩色合成、分类处理、差值运算提取出长山列岛新增建设用地,生成新增建设用地矢量数据,结合GIS软件MapInfo,经过投影转换、叠加分析、缓冲区分析、空间信息统计,分析新增建设用地的空间分布及影响机制,结果表明:长海县的建设用地在1993-2005年不同程度地增加,人口及经济发展是建设用地增加的主要促进因子;交通干线对新增加的建设用地具有空间吸引效应;新增建设用地有向港口等基础设施集中的特征;新增建设用地空间分布受到已有产业功能分区的影响.研究表明,RS&GIS支持下,利用TM数据分析海岛建设用地变化具有一定的应用前景. 相似文献
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LI Dong ZHAO Jun LIU Chenggang SUN Chengjun CHEN Jianfang PAN Jianming HAN Zhengbing HU Ji 《海洋湖沼学报（英文）》2020,(3):619-633
Knowledge about organic carbon loadings(ratio of sedimentary organic carbon(SOC)content to specific surface area(SSA))and the fate of organic carbon(OC)is critical to understand the marine carbon cycle.We investigated the variations in the patterns of OC loadings and the preservation capacities of sedimentary OC in the Yap Trench and other marine environments.The average OC loading in sediment cores from various marine environments decreases with increasing water depth at a rate of^0.06 mg OC/(m^2·km)(R^2=0.23,P<0.01).Distinct low OC loadings(0.09±0.04 mg OC/m^2)were observed in the Yap Trench,with the lowest values as^0.02 mg OC/m^2.A further comparative analysis indicated that OC/SSA=0.2 mg OC/m^2 is a good indicator to distinguish between oxic deep-sea regions and suboxic energetic deltaic areas.Regression analysis between OC loading and bulk carbon isotope compositions indicates that marine OC(δ13C^-20.4‰to-18.6‰)dominates the lost OC within the Yap Trench and does not differ from that of the abyssal zone.In contrast,terrestrial OC withδ13C values of approximately-27.4‰to-20.5‰was the major source of remineralized OC in the sublittoral zone.The ratios of OC loadings in the bottom layer relative to those in the top layers of sediment cores indicate that the preservation capacities of hadal trenches are much lower than those of other environments,and only approximately 30%of the SOC deposited in hadal trenches is finally buried.The value is equivalent to 0.066%of the primary production-derived OC and much lower than the global ocean average(~0.3%).Overall,the hadal zone exhibits the lowest OC loading and preservation capacity of SOC of the different marine environments investigated,despite the occurrence of a notable funneling effect. 相似文献
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Large-scale interceptors constitute the main structure of offshore self-driven floating marine litter collection devices,and the structural stability of such interceptors under the action of waves directly influences the overall safety of the device.When the ratio of the diameter of a horizontal cylinder in such interceptors to the incident wavelength is larger than 0.25,the wave force can be calculated by using the diffraction theory,by considering the problem as that of the interaction between the waves and a partially immersed large-scale horizontal cylinder.In this study,an analytical approach to calculate the wave force on a partially immersed large-scale horizontal cylinder was formulated by using the stepwise approximation method.Physical model tests were conducted to investigate the effects of different factors(wave height,period,and immersion depth)on the wave force on a large-scale horizontal cylinder under conditions involving short-period waves.The results show that both horizontal and vertical wave forces on the cylinder increase as the wave height(immersion depth)increases in most cases.The vertical wave force decreases with the decrease of the period.For the horizontal wave force,it increases with the decrease of the period when the wavelength is larger than the diameter of the cylinder and decreases with the decrease of the period when the wavelength is smaller than the diameter of the cylinder. 相似文献
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Compared with bottom-fixed wind turbines,the supporting platform of a floating offshore wind turbine has a larger range of motion,so the gyroscopic effects of the system will be more obvious.In this paper,the mathematical analytic expression of the gyroscopic moment of a floating offshore wind turbine is derived firstly.Then,FAST software is utilized to perform a numerical analysis on the model of a spar-type horizontal axis floating offshore wind turbine,OC3-Hywind,so as to verify the correctness of the theoretical analytical formula and take an investigation on the characteristics of gyroscopic effect.It is found that the gyroscopic moment of the horizontal axis floating offshore wind turbine is essentially caused by the vector change of the rotating rotor,which may be due to the pitch or yaw motion of the floating platform or the yawing motion of the nacelle.When the rotor is rotating,the pitch motion of the platform mainly excites the gyroscopic moment in the rotor’s yaw direction,and the yaw motion of the platform largely excites the rotor’s gyroscopic moment in pitch direction,accordingly.The results show that the gyroscopic moment of the FOWT is roughly linearly related to the rotor’s inertia,the rotor speed,and the angular velocity of the platform motion. 相似文献
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Using sea surface salinity(SSS)observation from the soil moisture active passive(SMAP)mission,we analyzed the spatial distribution and seasonal variation of SSS around Changjiang River(Yangtze River)Estuary for the period of September 2015 to August 2018.First,we found that the SSS from SMAP is more accurate than soil moisture and ocean salinity(SMOS)mission observation when comparing with the in situ observations.Then,the SSS signature of the Changjiang River freshwater was analyzed using SMAP data and the river discharge data from the Datong hydrological station.The results show that the SSS around the Changjiang River Estuary is significantly lower than that of the open ocean,and shows significant seasonal variation.The minimum value of SSS appears in July and maximum SSS in December.The root mean square difference of daily SSS between SMAP observation and in situ observation is around 3 in both summer and winter,which is much lower than the annual range of SSS variation.In summer,the diffusion direction of the Changjiang River freshwater depicted by SSS from SMAP is consistent with the path of freshwater from in situ observation,suggesting that SMAP observation may be used in coastal seas in monitoring the diffusion and advection of freshwater discharge. 相似文献
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我国是管理海域辽阔,海岸线漫长,资源丰富的海洋大国。大力发展海洋事业,事关国家的长治久安和经济社会的可持续发展。加强对海洋的观测和了解,准确预报海洋灾害,合理开发利用海洋资源,努力保护海洋生态环境,有效维护国家海洋主权与权益,是广大海洋工作者和海洋管理部门的神圣使命和战略任务。国家海洋局从建局以来,就一直积极发展海洋科学技术,着力强化海洋观测系统建设,不断提高对海洋的持久观测能力,为海洋事业实现跨越式发展提供了强有力的支撑。 相似文献
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2011年9月17日是国际海岸清洁日。由辽宁省盘锦市保护斑海豹志愿者协会发起,盘锦市180多名环保志愿者来到辽河入海口的斑海豹栖息地三道沟和六道沟海岸,捡拾海边不可降解的白色垃圾。这是盘锦市第一次组织和参与国际海岸清洁日活动。这次活动早在8月就在盘锦市保护斑海豹志愿者协会论坛上发帖通知,并在《辽河晚报》发布了征召志愿者的公告。协会会员和广大志愿者积极报名参加,上至70多岁的老人,下至7、8岁的孩童,有的是一家三口自驾车参加活动。17日是个周末, 相似文献