全球Stokes 漂流的时空分布特征研究

利用海浪模式WWIII(Wave Watch III)2008年的模拟结果对海面Stokes漂流、Stokes输运、Stokes深度以及全球Langmuir数的年平均分布特征和季节平均分布特征分别进行了详细的研究与分析。结果表明,海面Stokes漂流和Stokes输运均呈现高纬度偏大的特征,以南极绕极流海域最为突出。全球大部分海域Stokes漂流影响深度在20 m以内,呈现大洋东部偏大,西部偏小的分布特征。全球大部分海域的混合作用是剪切不稳定性和Langmuir湍效应并存的状态,甚至有些海域是以Langmuir湍效应为主。因此,在进行大尺度的海洋数值模拟时,应该考虑波浪导致的混合效应。     

Stokes漂流对全球海表面温度模拟的影响

Stokes漂流对海洋上混合层中的流场和温度场结构具有不可忽视的作用。本文基于WAVEWATCHⅢ海浪模式模拟的海浪要素计算得到Stokes漂流,将其引入SBPOM模式的动量方程中,从体积输运的角度研究Stokes漂流对全球海表面温度的影响。分析发现Stokes漂流与Stokes输运在全球呈现高纬度强于中低纬度的带状分布特征,且这种流动与输运对全球海表面温度具有降温作用,该降温作用的分布与全球Stokes输运强度相对应,高纬降温作用大于中低纬度,特别是南极绕极流海域平均降温明显大于其余海域,最大降温可达1.5℃,且全球月平均降温超过0.1℃。     

Stokes漂流对海洋上层混合层的影响研究

在总结前人研究的基础上,对N-S方程进行波浪平均,得到新的包括Stokes漂流影响的三维数值模型,并将其应用到三维环流模式POM中。对方程无因次化,选定了3个主要参数进行研究,分别为Rossby数,Langmuir数和Hoe-nikker数。利用新的POM模型,设计理想实验进行研究。结果表明,混合方案等外部条件不变时,大、中尺度对应的混合系数和湍动能变化较小。Langmuir数越小,Stokes漂流的贡献越大,对平均流的影响越大,垂向不稳定性越强,混合系数越大。Hoenikker数为负值时,温度降低,混合系数值变大,混合深度变深。Hoenikker数为正值时,上层海水温度升高,混合系数值变小,混合深度变浅。     

台风过程中浪致Stokes漂流对海洋上层温度影响的数值模拟

Stokes漂流对海洋上层温度变化具有重要影响。本文以"麦德姆(Matmo)"台风过程为例,基于浪流耦合模型,通过对比分析考虑和未考虑Stokes漂流的模拟结果,研究了台风过程中浪致Stokes漂流及其效应对海洋上层温度变化的影响。研究表明Stokes漂流及其效应与海浪大小的分布密切相关,海浪越大, Stokes漂流、Stokes输运和Ekman-Stokes数相对越大。Stokes漂流在台风过程中起降低海表面温度的作用,台风路径处的Stokes漂流及其效应较大,降温较明显,最大降温约2°C。产生降温的原因是Stokes漂流造成海表流场改变,以及Stokes输运引起海水辐散等作用加强了上下层海水质量和能量的交换。利用Argo资料进行验证,发现考虑了Stokes漂流作用的海洋上层温度模拟结果与Argo测量结果更接近。     

Stokes漂流近似公式对海洋表层流场估算的影响

本文采用波浪订正的Ekman模型,研究分析了三种Stokes漂流近似公式(单波公式、e指数公式、Phillips谱近似公式)对海洋表层流场估算的影响。海表总流场由海表面高度(SSH)数据计算的地转流和海浪模式WAVEWATCH Ⅲ输出结果计算的非地转流组成,并采用拉格朗日浮标观测数据对计算结果进行了验证。研究表明,随着Stokes漂流近似公式精度的提高,其计算的拉格朗日流速更接近于谱积分公式的计算结果,更贴近拉格朗日浮标观测数据。与谱积分公式计算的海表拉格朗日流速相比,单波公式的平均相对偏差为0.0834,e指数公式的平均相对偏差为0.0392,Phillips谱近似公式的平均相对偏差为0.0101,说明Phillips谱近似公式在不同风速下均能对谱积分公式有良好的近似效果。在低风速条件下,由Stokes漂流近似公式精度引起的海洋表层流场估算误差可以忽略不计,但随着风速增加,由近似公式精度引起的偏差逐渐变大,此时应该选择Phillips谱近似公式计算Stokes漂流,来减小误差。     

三种基于均生函数的统计模型在厄尔尼诺预测中的应用

为了探究厄尔尼诺的预测方法,提高其预报准确度与预报时效,本文基于均生函数的基本原理,在普通均生函数模型中分别加入气候序列的本征模函数和预报因子变量,构建了基于EEMD(Ensemble EmpiricalModeDecomposition)的均生函数模型和多变量均生函数模型;并应用三种方案对NINO3区海温指数进行了预报试验。结果表明,两种改进模型对厄尔尼诺的预报效果好于普通均生函数模型,是提高预报准确度的有效手段;同时,利用统计的预报模型,可以在一定程度上有效延长厄尔尼诺的预报时效,具有一定实践意义。     

海洋沉积证据在低纬过程气候变化中的应用及展望

在国内外研究的基础上, 对印太暖池区的沃克环流和厄尔尼诺-南方涛动（ENSO）、热带辐合带（ITCZ）等低纬过程的空间分布和随时间的变化规律及其研究方法进行初步归纳,并指出研究中存在的问题。本文论述了厄尔尼诺-南方涛动变率在全新世早期及中世纪气候异常期（1 000～700 a BP）的晚期逐渐增强,介绍了热带辐合带在BA暖期（Bølling-Allerød Warm Period）和前北方期（pre-Boreal,10.3～9.5 ka BP）的北移,以及在新仙女木事件（Younger Dryas Event,12.5～11.5 ka BP）和北大西洋冷期（距今7.5～5 ka BP）期间的南移。对低纬过程长时间尺度轨道周期的探讨表明, 末次冰盛期赤道东太平洋出现了较偏南的热带辐合带锋面系统,甚至在1.65 Ma冰期,热带辐合带也有快速南移的证据。海洋沉积的粒度、黏土矿物、陆源粉尘、元素和同位素、有孔虫分析等研究方法在推测厄尔尼诺-南方涛动和热带辐合带位移中有很好的应用,建议以陆源生态系统对气候的响应为切入点、以孢粉为手段来探讨陆源植被、气候、火灾和海-陆大气环流等低纬过程的变化特征,进而反演沃克环流（或厄尔尼诺-南方涛动）演化和热带辐合带位移的影响。     

微藻在海水鱼类苗种培育过程中的作用

主要从营养、促摄食以及益生作用三方面来综述微藻在海水鱼类苗种培养过程中的作用。在海水鱼类苗种培育过程中,微藻(microalgae)已得到广泛应用。由于绿藻的应用常使养殖水体呈现绿色,被形象地称为绿水养殖(green water culture)模式。微藻的作用首先是作为营养源直接供给仔鱼营养,或通过轮虫(Brachionus plicatilis)等生物饵料的富集或载体作用间接为仔鱼传递营养物质;微藻还可以通过提供微量营养元素在仔鱼摄食行为的建立、调节以及消化生理的刺激等方面发挥作用。除营养作用外,添加微藻还具有改善水质、增加水体混浊度和光对比度的作用,从而提高食饵的背景反差,增加海水仔鱼的摄食率。此外,微藻也可以调节养殖水体以及仔鱼肠道的微生态系统,维持水体及仔鱼肠道的菌群平衡,通过发挥益生作用减少病原菌的暴发。     

营养盐在东海春季大规模赤潮形成过程中的作用

为研究营养盐在东海大规模赤潮形成过程中的作用,分别于2004,2005年春季在东海赤潮爆发前进行了2个航次的海上调查。调查结果显示:DIN,PO4-P,SiO3-Si浓度分别高达15,0.55,15μmol.L-1以上,调查海域整体上处于富营养化状态;受陆源输入影响,调查区域营养盐分布呈现出近岸高、外海低,等值线走向与岸线基本平行的特点。同2004年相比,2005年春季调查海域营养盐高值区明显外扩,营养盐水平整体升高:其中DIN浓度升高9%、PO4-P升高18%、SiO3-Si升高60%,硅磷比上升60%,硅氮比上升了47%。研究结果表明,较高的营养盐浓度水平,较高的硅酸盐含量以及较高的硅磷比、硅氮比值是2005年春季优先爆发大规模硅藻赤潮的重要原因之一。     

生态因子在黄海绿潮生消过程中的作用

2008–2017年南黄海海域连续10 a发生绿潮,影响周边沿海城市养殖、旅游和航运安全等。研究绿潮生消过程及其影响因素对于理解黄海绿潮分布特征,开展绿潮灾害的预防与治理有重要意义。本文主要采用MODIS L1B数据,通过归一化植被指数提取绿潮信息。根据逐年绿潮覆盖面积的变化特征,将绿潮生消过程分为3个阶段:触发阶段、快速发展阶段、消衰阶段,分析了海表温度、降水和光照在绿潮生消过程中的作用。结果表明:在触发阶段,温度达到15°C后,有效降水可以刺激绿潮的触发,在降水后的半个月内可以通过MODIS影像发现绿潮。在快速发展阶段,绿潮所在位置海表面温度为16～21°C,适宜绿潮的快速生长;太阳短波辐射集中在250～280 W/m2范围内;降水量是影响绿潮生长规模的一个重要因素,降水量少时绿潮覆盖面积峰值明显较小,而出现绿潮覆盖面积最大值的2016年降水量也极高。在消衰阶段,海表温度上升至22～26°C,绿潮在卫星影像中消失时,平均海表温度超过26°C,最高温度可达27.48°C,较高的海表面温度是导致绿潮消亡的主要原因之一;太阳短波辐射集中在240～260 W/m2,略低于快速发展阶段光照范围;降水量在该阶段相对充足不再影响绿潮的生长。     

南太平洋副热带偶极子对南太平洋辐合带的影响

为研究南太平洋副热带偶极子的局地气候效应,利用Hadley中心的海温数据集Had ISST以及NCEP-NCAR的大气再分析数据,分析了南太平洋副热带偶极子(South Pacific Subtropical Dipole,SPSD)对南太平洋辐合带(South Pacific Convergence Zone,SPCZ)的影响,并探讨了相应的物理过程。研究结果显示,南太平洋副热带偶极子事件线性独立于ENSO(El Ni?o-Southern Oscillation)事件,有明显的季节锁相,于12~2月达到峰值并显著影响SPCZ降水带的位置。其中,正偶极子事件(简称"正事件")期间偶极子东北极区域(暖海温)水汽辐合上升,降水增多;而在偶极子西南极区域(冷海温)水汽辐散下沉,降水减少,因此SPCZ降水带偏北。负偶极子事件(简称"负事件")则相反,东北极降水减少的同时西南极降水增多,从而SPCZ降水带偏南。本研究关于SPSD与SPCZ关系的分析,将有助于更好地理解南太平洋的年际气候变异和海气相互作用。     

Preliminary study on decadal variations of EI Nino-associated adjustment in the tropical Pacific thermocline

Statistical analysis about ENSO index represented by SSTA in Nino3 with several datasets shows obviously decadal changes in the dominant period and amplitude of ENSO. Correlation analysis about the composite El Nino events before and after 1976 exhibits obviously decadal changes in the propagation and intensity of the oceanic anomaly related to the variation of SSTA in Nino3. In the composite El Nino before 1976, the coherence is relatively weak between the oceanic anomaly in the tropical Pacific and the SSTA in the Nino3 region; the area with significant correlation coefficient is relatively small; the oceanic anomaly related to Nino3 SSTA propagates faster. The above changes correspond well to the decadal changes of ENSO cycles. Some preliminary explanations are given based on the analysis of the decadal changes in the thermocline. The tropical thermocline shoals after 1976 except in the equatorial far East Pacific and the inclination of the tropical thermocline deep west and shallow east patterns wea     

Decline of Terebralia palustris in South African mangroves

Terebralia palustris (Linnaeus, 1767), the giant mangrove whelk, is a prominent component of mangrove ecosystem malacofauna in the Indo-West-Pacific region. On the east coast of Africa, the range of T. palustris extends from Kenya to the south-eastern region of South Africa. Here we confirm reports that, in the past three decades, South African populations of T. palustris have declined. Terebralia palustris was recorded from only two estuarine mangrove forests during a survey conducted in 2013/2014, compared with six estuaries in the mid-20th century. At Kosi Bay, the average density was 186 ind. m^-2 (SD 106) in comparison to only 7.1 ind. m^-2 (SD 2.5) at Durban Bay. Additionally, the average shell height of individuals at Durban Bay (60.3 mm; SD 13.6) was larger than at Kosi Bay (31.84 mm; SD 16.09), indicating the absence of juvenile snails at Durban. In South Africa there have been no previous ecological assessments for T. palustris and, aside from one detailed survey in the early 1960s, most of the occurrence records are vague and incomplete. The ultimate causes for the decline of this charismatic gastropod in South Africa are unknown, although habitat loss and degradation are suspected. Further research is urgently required, particularly into aspects concerning its disappearance at the limit of its global distribution.     

Neon distribution in South Atlantic and South Pacific waters

We present and assess the distribution of neon in South Atlantic and South Pacific waters, on the basis of more than 3000 mostly new neon data which were obtained primarily under the hydrographic program of the World Ocean Circulation Experiment (predominantly southern summer to fall cruises). Data precision is better than±0.5%, and the set is internally consistent within±0.3% and partly better, and compatible with reported high-quality neon values. Using suitably averaged data (precision 0.1–0.3%), we find that the total range of neon anomalies relative to a solubility equilibrium with atmospheric neon at the observed potential temperature and salinity (using the solubilities of Weiss, J. Chem. Eng. Data 16 (1971) 235) is approximately 0–4%, and below 2000 m depth, 3–4% only. We consistently observe two types of neon depth profiles, one for the temperate-latitudes ocean, which is characterized by a near-surface maximum and a minimum in Antarctic Intermediate Water, and one for the Southern Ocean that essentially displays a steady increase with depth. The neon distribution reflects the influence of air injected by submerged air bubbles, the areal distribution of atmospheric pressure, seasonal temperature changes in the mixed layer and solar heating below it, and interaction with sea ice and glacial ice, largely in keeping with previous work. However, it appears that interaction with sea ice reduces neon anomalies distinctly less than the literature suggests. The temperate-ocean shallow maxima point to widespread subsurface heating in the course of the summer season by roughly 1 K. Among the major source water masses of the deep waters, the neon anomalies are lowest in Antarctic Intermediate Water (∼1.5%), intermediate in North Atlantic Deep Water (∼3%, confirming previous work) and similarly in Circumpolar Deep Water, and highest in Antarctic Bottom Water (∼3.8%). The anomalies in Southeast Pacific deep waters (>2500 m) are comparatively less (only∼3.3%), as a result of the contribution of Antarctic Intermediate Water. The present study is the first attempt to deal with the oceanic distribution of neon in a systematic fashion. The results can serve to assist assessments of the oceanic distributions of other dissolved gases.     

全新世时期热带太平洋西部表层温度和盐度的降低

在现今的气候条件下,热带太平洋西部(WTP)的表层水盐度偏低,向该盆地的东部有增加的趋势。热带太平洋表层水的盐度被认为受大气层对流、降雨、蒸发和大洋动力等综合因素的控制,而年间时间表上的明显变化多与厄尔尼诺-南方涛动(ENSO)循环有关,然而,人们很少知道这个大洋-大气耦合系统在百年、千年时间表上的变化情况。     

南太平洋南极中层水的中尺度特征

The Argo float observations are used to investigate the mesoscale characteristics of the Antarctic Intermediate Water(AAIW) in the South Pacific in this paper. It is shown that a subsurface mesoscale phenomenon is probably touched by an Argo float during the float's ascent-descent cycles and is identified by the horizontal salinity gradient between the vertical temperature-salinity profiles. This shows that the transportation of the AAIW may be accompanied with the rich mesoscale characteristics. To derive the spatial length, time, and propagation characteristics of the mesoscale variability of the AAIW, the gridded temperature-salinity dataset ENACT/ENSEMBLE Version 3 constructed on the in-situ observations in the South Pacific since 2005 is used. The Empirical Mode Decomposition method is applied to decompose the isopycnal-averaged salinity anomaly from26.8 σθ–27.4 σθ, where the AAIW mainly resides, into the basin scale and two mesoscale modes. It is found that the first mesoscale mode with the length scale on the order of 1 000 km explains nearly 50% variability of the mesoscale characteristics of the AAIW. Its westward-propagation speeds are slower in the mid-latitude(around 1cm/s) and faster in the low latitude(around 6 cm/s), but with an increasing in the latitude band on 25°–30°S. The second mesoscale mode is of the length scale on the order of 500 km, explaining about 30% variability of the mesoscale characteristics of the AAIW. Its westward-propagation speed keeps nearly unchanged(around 0.5cm/s). These results presented the stronger turbulent motion of the subsurface ocean on the spatial scale, and also described the significant role of Argo program for the better understanding of the deep ocean.     

南太平洋海浪特点的统计分析

根据1950-1995年的南太平洋气象船舶报资料,对5°×5°网格统计的风浪和涌浪的要素进行分析,得出了南太平洋风浪和涌浪的变化规律和分布特点.南太平洋海浪场与北半球各大洋相比,季节变化不显著,但仍有明显的季节变化,低纬常年盛行东南向浪,高纬则盛行偏西向浪,本文通过分析每月风浪、涌浪的盛行方向、波高及周期等值线图,研究阐明了南太平洋各要素的分布规律,为船舶远洋交通运输、远洋出访和科学实验提供了较翔实的海浪资料及变化规律.     

太平洋南部菲尼克斯海岭的年代学

菲尼克斯岩石圈板块是太平洋中面积最大的板块之一。它从侏罗纪就开始形成,然后沉降于俯冲区。如今菲尼克斯板块只剩下位于菲尼克斯海岭古扩张轴、南设得兰海槽俯冲区和赫洛、沙克尔顿转换断层之间不大的一块地方。     

Geographic variation in the assemblages of leptocephali in the western South Pacific

A sampling survey was carried out to study the distribution and ecology of leptocephali in several different areas of the western South Pacific between 160 and 175°E during August and September of 1995. The survey included transects of stations across the westward flowing South Equatorial Current (SEC) region to the northwest of Fiji and south to 30°S, a transect to the north of the Tasman Front, and a transect that passed through the Solomon Islands. A total of 2362 leptocephali of at least 94 species of 13 families of eels and other elopomorph fishes were collected. The most abundant leptocephali in the region were of the marine eel families Serrivomeridae, Congridae, Nemichthyidae, and Muraenidae of the order Anguilliformes. The leptocephali of shallow water eels of the Chlopsidae, Moringuidae, Muraenidae, and Ophichthidae were most abundant and present at a wide size range in the low salinity “Fresh Pool”, which is also located closest to the major islands in the SEC region. Anguillid leptocephali were also most abundant in the SEC region and several species appeared to be spawning at that latitude. Cluster analysis and ordination of the catch rates of leptocephali suggested there were four regional assemblages related to the offshore spawning of mesopelagic serrivomerid eels, the presence of anguillid leptocephali in the SEC region and the relationship between the regional ocean current patterns and the geography of islands where shallow water marine eels live and probably spawn nearby. More impoverished assemblages were found in the southern regions where there are fewer islands, colder, higher salinity surface waters, and predominantly eastward flow. These findings support the hypothesis that various taxa of anguillid and marine eels use different spawning and recruitment strategies in the western South Pacific region as has been suggested by studies on leptocephali in the Northern Hemisphere.     

Law and order at sea in the South Pacific: the contribution of the Pacific Patrol Boat project

Under the Pacific Patrol Boat (PPB) program, Australia has supplied twenty-two 31.5 m patrol boats to 12 island countries in the South Pacific. While the primary task of these boats is fisheries protection, they have also been used for a range of other national tasks, including search and rescue, medical evacuations, hydrographic surveying, anti-smuggling and sovereignty patrols. As well as the boats themselves, the program comprises resident maritime surveillance and technical advisers, crew training and through-life logistic support. The PPB program has proven to be highly successful with the benefits of the program exceeding those originally sought by the Australian Department of Defence in establishing the program.