Wave-current interaction during Typhoon Nuri(2008)and Hagupit(2008):an application of the coupled ocean-wave modeling system in the northern South China Sea

The northern South China Sea(SCS) is frequently affected by typhoons. During severe storm events, wave-current interactions produce storm surges causing enormous damage in the path of the typhoon. To evaluate the influence of wave-current interactions on storm surge, we used a coupled ocean-atmospherewave-sediment transport(COAWST) modeling system with radiation-stress and vortex-force formulations to simulate two typically intense tropical storms that invaded the SCS, namely Typhoons Nuri(2008) and Hagupit(2008), and compared results with observations from the Hong Kong Observatory. Both radiationstress and vortex-force formulations significantly improved the accuracy of the simulation. Depending on which typhoon and the topography encountered, the influence of surface waves on the oceanic circulation showed different characteristics, including the differences of range and intensity of storm surge between vortex-force and radiation-stress experiments. During typhoon landing, strong sea-surface elevation in concert with wave set-up/set-down caused the adjustment of the momentum balance. In the direction perpendicular to the current, but especially in the cross-shore direction, the pressure gradient and wave effects on the current dominated the momentum balance.

基于命中概率的海警舰炮对海试射问题研究

为研究水面舰艇在维权执法任务中舰炮武器试射问题,提高海警舰艇舰炮武器运用能力,基于舰炮命中概率构建了仿真模型,通过仿真计算得出了不同试射决策下目标分布概率误差随射击距离的变化,并分析了射击命中概率与射击距离的关系,进一步得出了海警舰艇试射决策:即当射击距离小于等于4500 m时不应进行试射,且射击距离小于4000 m时,不试射的命中概率较高与不引入新误差的命中概率几乎一致;当射击距离大于4500 m时,可根据现场情况进行试射。研究成果可以为海警舰艇执行维权任务提供参考。

Water mass of the northward throughflow in the Bering Strait in the summer of 2003

The temperature and salinity data obtained by the Chinese national arctic research expedition （CHINARE2003） are used to study the water structure in the Bering Strait and ambient regions. Four water masses appeared in the research region： the intermediate Bering Sea water mass （IBWM）, the Alaska coastal water （ACW）, the Anadyr water （AW） and the Bering shelf water （BSW）. The AW originates from the IBWM, but the upper layer water has been greatly altered. In the cruise on 28/29 July 2003, there were only the BSW and ACW in a section across the Bering Strait （BS section）, but in the September 12/13 cruise, the AW, BSW and ACW flowed parallelly into the Bering Strait. The upper waters of these water masses were all altered due to ice melting, runoff, solar radiation, and wind mixing. The waters in the central and northern parts of Bering Strait stratified by two uniform layers,were expressed as the typical feature of the water masses originating from the pacific. A two-layer structure also dominated the vertical stratification in most part of the Chukchi Sea. An obvious subseasonal variation was observed in the BS section, which caused varying transportation of fresh water, heat, and substance, and produced a long-term and extensive impact on the Arctic Ocean.

Long-Term Characterization of Sea Conditions in the East China Sea Using Significant Wave Height and Wind Speed

In this study, the statistical characterization of sea conditions in the East China Sea(ECS) is investigated by analyzing a significant wave height and wind speed data at a 6-hour interval for 30 years(1980–2009), which was simulated and computed using the WAVEWATCH Ⅲ(WW3) model. The monthly variations of these parameters showed that the significant wave height and wind speed have minimum values of 0.73 m and 5.15 ms^(-1) and 1.73 m and 8.24 ms^(-1) in the month of May and December, respectively. The annual, seasonal, and monthly mean sea state characterizations showed that the slight sea generally prevailed in the ECS and had nearly the highest occurrence in all seasons and months. Additionally, the moderate sea prevailed in the winter months of December and January, while the smooth(wavelets) sea prevailed in May. Furthermore, the spatial variation of sea states showed that the calm and smooth sea had the largest occurrences in the northern ECS. The slight sea occurred mostly(above 30%) in parts of the ECS and the surrounding locations, while higher occurrences of the rough and very rough seas were distributed in waters between the southwest ECS and the northeast South China Sea(SCS). The occurrences of the phenomenal sea conditions are insignificant and are distributed in the northwest Pacific and its upper region, which includes the Southern Kyushu-Palau Ridge and Ryukyu Trench.

Benthic Habitat Quality Assessment Based on Biological Indices in Xiaoqing River Estuary and Its Adjacent Sea of Laizhou Bay,China

Based on the macrofauna data(2008-2011) in Xiaoqing River estuary and its adjacent sea, Laizhou Bay of Bohai Sea, China, the AZTI Marine Biotic Index(AMBI) and Multivariate AMBI(M-AMBI) were used for benthic habitat quality(BHQ) assessment. Results showed that BHQ presented an obvious trend of improvement along the direction of stream channel and river mouth, and in the coastal areas. AMBI and M-AMBI were significantly related to environmental pressure gradient data. Therefore, the two indices can well indicate BHQ in the studied area. However, there were significant differences between results of the two indices. In the cases of low taxa number and high abundance of single species, AMBI might overestimate BHQ. We thus adjusted its thresholds to solve this problem. And M-AMBI might overestimate BHQ when benthic assemblage was dominated by the opportunistic species. Then we could raise the weight of AMBI in the calculation of M-AMBI to handle the problem.

Suspended Sediment Transport and Deposition in the Zhoushan Archipelago Sea Area

The transport mechanism and settlement characteristics of suspended sediments are analyzed in this article on the basis of measured data. Results indicate that the concentration and flux of suspended sediments decrease sharply from Hangzhou Bay to the offshore area. Suspended sediment transport is mainly controlled by advection transport and gravitational circulation transport. The settling velocity of suspended sediments gradually decreases from Hangzhou Bay to the offshore area. The settlement of suspended sediments mainly takes place during the turning phase of the tidal currents.

Numerical simulation of the Kuroshio intrusion into the South China Sea by a passive tracer

Owing to lack of observational data and accurate definition,it is difficult to distinguish the Kuroshio intrusion water from the Pacific Ocean into the South China Sea（SCS）.By using a passive tracer to identify the Kuroshio water based on an observation-validated three-dimensional numerical model MITgcm,the spatio-temporal variation of the Kuroshio intrusion water into the SCS has been investigated.Our result shows the Kuroshio intrusion is of distinct seasonal variation in both horizontal and vertical directions.In winter,the intruding Kuroshio water reaches the farthest,almost occupying the area from 18°N to 23°N and 114°E to 121°E,with a small branch flowing towards the Taiwan Strait.The intrusion region of the Kuroshio water decreases with depth gradually.However,in summer,the Kuroshio water is confined to the east of 118°E without any branch reaching the Taiwan Strait; meanwhile the intrusion region of the Kuroshio water increases from the surface to the depth about 205 m,then it decreases with depth.The estimated annual mean of Kuroshio Intrusion Transport（KIT） via the Luzon Strait is westward to the SCS in an amount of –3.86×106 m3/s,which is larger than the annual mean of Luzon Strait Transport（LST） of –3.15×106 m3/s.The KIT above 250 m accounts for 60%–80% of the LST throughout the entire water column.By analyzing interannual variation of the Kuroshio intrusion from the year 2003 to 2012,we find that the Kuroshio branch flowing into the Taiwan Strait is the weaker in winter of La Ni？a years than those in El Ni？o and normal years,which may be attributed to the wind stress curl off the southeast China then.Furthermore,the KIT correlates the Ni？o 3.4 index from 2003 to 2012 with a correlation coefficient of 0.41,which is lower than that of the LST with the Ni？o 3.4 index,i.e.,0.78.

The shallow meridional overturning circulation in the South China Sea and the related internal water movement

The structure of the annual-mean shallow meridional overturning circulation （SMOC） in the South China Sea （SCS） and the related water movement are investigated, using simple ocean data assimilation （SODA） outputs. The distinct clockwise SMOC is present above 400 m in the SCS on the climatologically annual-mean scale, which consists of downwelling in the northern SCS, a southward subsurface branch supplying upwelling at around 10°N and a northward surface flow, with a strength of about 1x 108 ma/s. The formation mechanisms of its branches are studied separately. The zonal component of the annual-mean wind stress is predominantly westward and causes northward Ekman transport above 50 m. The annual-mean Ekman transport across 18°N is about 1.2×106 m^3/s. An annual-mean subduction rate is calculated by estimating the net volume flux entering the thermocline from the mixed layer in a Lagrangian framework. An annual subduction rate of about 0.66×106 ma/s is obtained between 17° and 20°N, of which 87% is due to vertical pumping and 13% is due to lateral induction. The subduction rate implies that the subdution contributes significantly to the downwelling branch. The pathways of traced parcels released at the base of the February mixed layer show that after subduction water moves southward to as far as 1 I^N within the western boundary current before returning northward. The velocity field at the base of mixed layer and a meridional velocity section in winter also confirm that the southward flow in the subsurface layer is mainly by strong western boundary currents. Significant upwelling mainly occurs off the Vietnam coast in the southern SCS. An upper bound for the annual-mean net upwelfing rate between 10° and 15°N is 0.7×108 ma/s, of which a large portion is contributed by summer upwelling, with both the alongshore component of the southwest wind and its offshore increase causing great upwelling.

Inversion Study on Pollutant Discharges in the Bohai Sea with the Adjoint Method

The adjoint method is presented which could be used to estimate the time-varying contamination concentration(CC) from pollution source(PS). Then the pollutant flux is calculated. In order to guarantee the continuity of pollutant distribution and make the calculated results more accurate, the independent point(IP) scheme is proposed. The contamination concentrations(CCs) at some time steps are selected as the independent points(IPs), and only CCs at these IPs are optimized while CCs at other points are calculated through linear interpolation of the independent CCs. In twin numerical experiments, all the given distributions are successfully inverted with the adjoint method. The cost functions and the mean absolute errors(MAEs) in concentrations and pollutant fluxes decrease greatly after assimilation, and the cost functions are reduced by about 5 orders of magnitude compared with their initial values. The results indicate that the adjoint method is computationally efficient to recover CCs from PS. It is easier to invert the given distribution which is less complex. The inversion efficiency with IP scheme is raised compared to that without this scheme. The IP scheme is significant for the inversion result, in which appropriate IP number could yield better inversion results. More work will be done to apply this method to real experiment.

Seasonal Cycle Analysis of the Nitrate Nitrogen and Nitrite Nitrogen in the Bohai Sea

During 1985-1987, the concentration of nitrate nitrogen was higher in the Laizhou Bay and the Bohai Bay while that of nitrite nitrogen was higher in the Liaodong Bay and the Bohai Bay. The concentration of nitrate nitrogen was highest in winter and lowest in summer while that of nitrite nitrogen was highest in autumn and lowest in spring. The seasonal variation of the concentration of nitrate nitrogen was maximum in the Laizhou Bay and the Bohai Bay while that of the concentration of nitrite nitrogen was maximum in the Liaodong Bay. There was a great difference in the concentration of nitrate nitrogen between the surface and the bottom in autumn and in the concentration of nitrite nitrogen between the surface and the bottom in summer. The main reason for the seasonal variations of the concentration of nitrate nitrogen and nitrite nitrogen was the marine biochemical process. The nitrate nitrogen and nitrite nitrogen in the Bohai Sea basically maintained a quasi-equilibrium state seasonal cycle. The quasi-equilibrium state seasonal cycle of nitrate nitrogen and nitrite nitrogen at the bottom was stable while that at the surface was liable to variations caused by other factors.

Research on the Propagation Acting of the Equatorial Planetary Waves on the Western Equatorial Pacific Warm Pool Heat

Based on the long-term buoy data from the Tropical Atmosphere Ocean ( TAO ) —array during the TOGA ( Tropical Ocean and Global Atmosphere ) Program (19801996), the propagation acting of the Equatorial planetary waves on the Western Equatorial Pacific warm pool heat is analyzed. Results show that the zonal heat transmission in the Western Equatorial Pacific takes palace mainly in the subsurface water and spreads eastwards along the thermocline; while the seasonal westward-spreading heat change structure occurs in the mixed layers in the middle and western Pacific. The standing-form transmission in the western Pacific appears in the thermocline layer, while in the eastern pacific, it exists in the mixed layer as well as in the thermocline layer. The standing-form and eastward-spreading sign of zonal heat transmitting in the upper water is predominant and strong, and the westward sign is weak.The component force of Kelvin Equatorial wave pressure runs through the western and eastern Equatorial pacific, and transmits heat energy eastwards. And the heat transmitted by zonal current component occurs mostly in the western Pacific; The heat transmitted by the component force of Rossby wave pressure mainly appears in the eastern and middle areas of the Pacific, while the zonal current component transmitting occurs mainly in the western Pacific; Mixed-Rossby gravity wave’s action on the zonal current is stronger than that of the thermocline layer. In the mean state, the standing wave model of Equatorial Pacific up layer ocean temperature confines the transport of western Pacific warm pool heat to the eastern Pacific. Under abnormal conditions, the standing wave model of Equatorial Pacific up layer ocean temperature weakens, the eastwardly transmitting model enhances, and subsequently n^the El Ni o event occurs.

Subtropical sea surface salinity maxima in the South Indian Ocean

Subtropical sea surface salinity(SSS)maximum is formed in the subtropical South Indian Ocean(SIO)by excessive evaporation over precipitation and serves as the primary salt source of the SIO.Spaceborne SSS measurements by Aquarius satellite during September 2011-May 2015 detect three disconnected SSS maximum regions(>35.6)in the eastern(105°E-115°E,38°S-28°S),central(60°E-100°E,35°S-25°S),and western(25°E-40°E,38°S-20°S)parts of the subtropical SIO,respectively.Such structure is however not seen in gridded Argo data.Analysis of Argo profile data confirms the existence of the eastern maximum patch and also reveals SSS overestimations of Aquarius near the western and eastern boundaries.Although subjected to large uncertainties,a mixed-layer budget analysis is employed to explain the seasonal cycle of SSS.The eastern and central regions reach the highest salinity in February-March and lowest salinity in August-September,which can be well explained by surface freshwater forcing(SFF)term.SFF is however not controlled by evaporation(E)or precipitation(P).Instead,the large seasonal undulations of mixed layer depth(MLD)is the key factor.The shallow(deep)MLD in austral summer(winter)amplifies(attenuates)the forcing effect of local positive E-P and causes SSS rising(decreasing).Ocean dynamics also play a role.Particularly,activity of mesoscale eddies is a critical factor regulating SSS variability in the eastern and western regions.

Huffman与LZW算法在海洋观测浮标通信数据压缩中的应用研究

在现有两种比较主流无损压缩算法基础上(Huffman算法和LZW算法),根据海洋观测浮标采集的观测数据特点,比较两种压缩算法的优缺点,并通过布放在西太平洋海域的一套观测浮标数据进行数据验证。结果表明,使用Huffman算法和LZW算法分别对海洋观测浮标数据进行压缩,两者的压缩率都基本可达50%左右甚至更低,Huffman算法压缩率较优,而LZW算法复杂度较优。通过分析,可证明这两种无损压缩算法都能有效地提高深远海通信效率和降低通信成本,同时也提高了科学观测数据的安全性和保密性,可根据实际情况选择在深远海观测浮标数据通信中应用。

黄河口及邻近海域浮游植物群落分布特征及与水环境的关系

根据2011—2014年5和8月黄河口及邻近海域浮游植物及水环境数据,探讨了研究海域浮游植物群落的空间分布特征及与水环境的关系。结果表明:调查期间共发现浮游植物108种,隶属于3门46属,其中硅藻门85种,占物种总数的78.7%,甲藻门22种,占20.4%,金藻门1种,占0.9%。5月的浮游植物细胞丰度(2.29×107个/m3)远小于8月(6.83×108个/m3),5和8月浮游植物Shannon-Winner多样性指数(H’)平均值分别为1.79和2.39。通过聚类分析将浮游植物群落和水环境划分为特征差异显著的两个区域(p<0.01):黄河口北部及东部离岸海域(Ⅰ组)和黄河口南部沿岸海域(Ⅱ组)。5月Ⅰ组温度(T)、pH、氮磷比(N:P)和化学耗氧量(COD)显著小于Ⅱ组(p<0.05),而水深(Depth)和溶解氧(DO)显著大于Ⅱ组(p<0.05),Ⅰ组优势种有斯氏根管藻、圆筛藻、具槽帕拉藻和印度翼根管藻,Ⅱ组优势种有斯氏根管藻和圆筛藻;8月Ⅰ组的水深、盐度(S)和透明度(SD)显著大于Ⅱ组(p<0.05),而无机氮(DIN)、COD和石油烃(TPH)显著小于Ⅱ组(p<0.05),Ⅰ组的优势种包括拟扭链角毛藻、佛氏海线藻、角毛藻和旋链角毛藻,Ⅱ组优势种包括柔弱角毛藻、中肋骨条藻、垂缘角毛藻、角毛藻、佛氏海线藻、拟扭链角毛藻和圆筛藻。调查海域水环境因子与优势种丰度的RDA结果表明,影响5月黄河口北部及东部离岸海域和南部沿岸海域浮游植物优势种空间分布差异的主要水环境因子为T、pH和COD,影响8月浮游植物优势种在2个区域分布差异的主要水环境因子有S和COD。

秦皇岛近岸海域保守污染物漂移的数值模拟与分析

采用FVCOM数值模型的水动力模拟结果为拉格朗日粒子追踪漂移模型提供背景潮流场,模拟了秦皇岛近岸7个河口保守污染物在风和潮流作用下的漂移轨迹,分析了两种作用对污染物在近岸运移轨迹的影响关系。结果表明:无风状态下,以金山嘴为界,金山嘴以南各河口粒子漂移距离相对较长,受到近岸潮流的影响,粒子运动轨迹与秦皇岛近岸流场走向相符;1级风力下,漂移轨迹顺着潮流的方向移动,漂移距离甚至会小于无风状态,尤其是1级风力下的NE风和NWN风;在2-3级风力下,风的去向即为粒子漂移的方向,风力越大漂移距离越远、漂移范围也越大。

鄂尔多斯盆地伊盟隆起上古生界储层孔隙结构特征及评价

储层是油气赋存的载体,其孔渗性能决定着后期油气开采难度以及可采数量。在众多影响储层孔渗性能的因素当中,储集层的孔隙结构发挥了关键的作用。通过对鄂尔多斯盆地伊盟隆起上古生界储层岩性以及孔渗参数进行分析,结果表明:石盒子组孔喉连通性及渗流性能最好,其次是山西组,太原组最差;依据压汞资料和毛细管压力曲线形态,孔隙结构类型可以划分为4类;通过孔渗资料统计分析,上古生界砂岩划分4类,并以Ⅱ类和Ⅲ类储层为主;砂体主要为冲积扇辫状水道砂体,曲流河、辫状河河道砂坝砂体以及三角洲平原分流河道砂体。研究结果可以为伊盟隆起区上古生界的油气开发提供依据。

北查尔斯王子山贝恩梅达特煤系煤层的煤岩学与煤化学特征

贝恩梅达特煤系是南极北查尔斯王子山地区发育的一套二叠纪含煤地层。在中国31次南极考察期间,从该地层单元的格洛索普特里斯冲沟段和麦金农段共采集了11件煤样品。为了了解这些煤的基本特征,开展了煤的煤岩学分析、工业分析和元素分析。煤的煤岩组分结果表明,两地层的煤均以有机组分为主(格洛索普特里斯冲沟段和麦金农段有机总量平均值分别为85.5%和91.1%),且镜质组和惰性组占主要比例;无机组分含量在两地层单元的煤中均较低且以黏土和氧化物(石英)为主,硫化物只出现在麦金农段局部煤中;两地层单元煤的最大反射率基本一致,平均值均为0.64%;工业分析结果表明麦金农段的煤具有特低-高灰分(9.85%~84.16%)、低-特低全水分(2.38%~6.18%)、高-特高挥发分(38.98%~66.76%)、低-特低硫(0.23%~0.68%)和中等-特低固定碳(5.26%~55.01%)特征;格洛索普特里斯冲沟段的煤具有中灰分(21.05%~29.40%)、低-中等全水分(7.44%~9.94%)、高挥发分(40.99%~43.67%)、特低硫(0.38%~0.44%)和低-特低固定碳(39.77%~46.59%)特征。两地层单元煤的焦渣特征为2。元素分析结果表明,麦金农段的煤属于低-特低磷(0.005%~0.019%)、低-高氟(108~829μg/g)、特低-高氯(0.017%~0.535%)和一级含砷(0~7μg/g)煤;格洛索普特里斯冲沟段的煤属于低-特低磷(0.006%~0.024%)、高氟(260~478μg/g)、中氯(0.007%~0.208%)和一级含砷(1~6μg/g)煤;格洛索普特里斯冲沟段煤属于褐煤,而麦金农段煤类型复杂,泥煤和烟煤均发育,类似于印度默哈讷迪盆地的煤。

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。

巴拿马运河扩建下的运河通行费博弈

巴拿马运河是世界主要运河之一,其扩建对全球航运市场影响巨大。文章建立竞争博弈模型,以巴拿马运河管理局和苏伊士运河管理局为博弈主体,对巴拿马运河扩建后双方运河通行费的调整策略进行博弈模型分析和赋值仿真。研究表明:巴拿马运河扩建后,巴拿马运河管理局应采取通行费小幅降价的策略,以吸引更多船舶通货量,尽快收回扩建成本;苏伊士运河的航运市场份额将有所缩减,但苏伊士运河管理局仍应维持现有通行费水平;双方以长远利益为目标选择策略,才能获得更高收益。

青岛某膜法海水淡化厂工艺设计

介绍了10万m^3/d规模青岛某膜法海水淡化厂的设计。其工艺采用了自动清洗微孔过滤+超滤膜预处理系统,两级反渗透除硼系统,能量回收系统,二氧化碳+饱和石灰水后处理系统,浓盐水排海系统等,产水与自来水1∶5混合后进入市政给水管网。