Volume flux and fresh water transport associated with the East Icelandic Current

The importance of the circulation of fresh water within the Nordic Seas has frequently been pointed out, especially its effect on deep water formation and therefore possibly on the thermohaline circulation. The main source of fresh water is the East Greenland Current entering the Nordic Seas through Fram Strait. The Jan Mayen Polar Current and the East Icelandic Current (EIC) carry a part of the fresh water into the Greenland and Iceland Seas respectively. As a part of the EU project VEINS, Aanderaa current meters were deployed on two moorings within the EIC from June 1997 to June 1998 on a standard CTD section from Langanes, Northeast Iceland, to the central Iceland Sea in the direction towards Jan Mayen. The current was mainly concentrated along the slope where it was baroclinic, while over the deeper part a weak barotropic flow was observed. Geostrophic calculations, referenced to the current meter data, were used for estimating the volume flux and fresh water transport with the current. The total transport over the section towards the east was found to be 2.5 Sv. The fresh water transport relative to a salinity of 34.93, above 170 m, amounted to 5.5 mSv. This is roughly 4% of the fresh water transport through Fram Strait. This transport is put into a long-term perspective using hydrographic data from the Langanes section.     

The Indian Ocean HydroBase: A high-quality climatological dataset for the Indian Ocean

The present study developed a high-quality climatological dataset for the Indian Ocean - the Indian Ocean HydroBase (IOHB) - from a combined dataset including the World Ocean Database 1998 version 2 (WOD98v2). Methods are similar to those used by previous studies for other oceans. Japanese data for the IOHB originated from the Japanese datasets MIRC (Marine Information Research Center) Ocean Dataset 2001 and Far Seas Collection; these datasets contain more Japanese observations than WOD98v2. Water mass properties in the IOHB climatology are consistent with previous studies. Seasonal patterns of properties near the sea surface are well reproduced, and deep-layer properties are consistent with the Reid-Mantyla climatology that is derived from high-quality observations. The isopycnal climatology of the IOHB differs from the World Ocean Atlas 2001 (WOA01) along the fronts associated with the Antarctic Circumpolar Current (ACC). The WOA01 shows a warm and saline intermediate water intrusion from South Africa to the east along the northern edge of the front. Such an intrusion is absent in IOHB where less saline intermediate water extends continuously northward from the southern ocean. The WOA01 shows a continuous belt of low potential vorticity along the ACC. This feature is less distinct in the IOHB climatology and in the Reid-Mantyla climatology. The IOHB consists of a 1° × 1° gridded climatology and the datasets of raw and quality-controlled hydrographic stations. The latter is valuable for quality control of the Argo float salinity data as climatological reference. These datasets are available freely via the Internet.     

9914号台风近海强度增强的主因分析

通过对9914号台风近海强度增强原因的分析后认为：台风中心高层流出场增强，辐散加大及弱冷空气触击台风北侧，是9914号台风近海强度增强的主要原因。     

Individual-based models of copepod populations in coastal upwelling regions: implications of physiologically and environmentally influenced diel vertical migration on demographic success and nearshore retention

We link a two-dimension coastal upwelling circulation hydrodynamic-ecosystem (NPZ) model with an individual-based model (IBM) for an intermediate sized (ca. 2.5 mm) copepod capable of diel vertical migration (DVM) at larger sizes. The NPZ model is that of Franks, Wroblewski and Flierl (1986), with the zooplankton state variable parameterized for macrozooplankton. IBM simulations are done with different scenarios for behavioral responses; the interaction of the organisms with the circulation is evaluated by examining growth/development, reproduction, survival and distribution. Since ocean productivity in coastal upwelling systems is greatest nearshore, zooplankton production is favored by nearshore retention. Model results, using an idealized, intermittently wind-forced, upwelling circulation, indicate that non-migrating copepods are flushed from the nearshore system in offshore zonal surface flow; highest population abundances occur offshore, in a region of relatively low food resources. Conversely, migrating copepods interact with the stratified zonal flow within the upwelling system and are retained nearshore when the amplitude of the DVM is sufficient to place the individuals in near-bottom onshore flow during the day. Environmental features, like deep-extending food resources, and physiological controls, like satiation or body size, that permit copepods to remain deeper, or spend more time away from the surface, favor nearshore retention. Diel vertical migration is one mechanism, which may permit animals to exploit favorable habitats located nearshore in upwelling systems.     

龙口港的假潮及成因探讨

利用 23 a （1964—1986 年）的假潮资料，讨论了龙口港假潮的振幅、频率、周期和持续时间等；给出了导致假潮的各种天气形势和风场；分析了不同气象要素对假潮的贡献；探讨了大和特大振幅假潮的成因。分析结果表明：风场变化是导致龙口港假潮的直接原因；100 cm 左右和 >150 cm 的大和特大振幅假潮，是龙口港特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果，该假潮具有较大危害性。     

南海海洋动力过程观测与模拟研究进展

主要从动力学角度回顾了近年来与南海环流有关的南海物理海洋学调查与模拟研究的进展。目前,对南海上层海洋海盆和次海盆尺度季节性环流的基本模态已经有了比较一致的认识,对特定区域中尺度的环流特征也达成共识。已有的观测和数值模拟研究工作在以下几个方面取得了很大的进展：研究南海准定常涡旋的空间分布,获得其时间演化的主要特征及影响其形成和演化的可能因素;研究行星波动在南海环流建立与调整过程中的作用,获得南海低阶行星波动的速度场分布以及南海环流建立与调整的典型时间尺度;分析并讨论南海与其周边海域,尤其是与西太平洋海域水交换的形式及其影响因素,初步了解海峡水交换的季节差异及其水平和垂向结构,提出黑潮入侵南海的几种形式。未来南海环流的研究方向将扩展到能量学机制方面,并包括热量、动能、动量和涡度等物理量的多时空尺度迁移。     

Structure and resilience of overwintering habitats of Calanus finmarchicus in the Eastern Norwegian Sea

Very high concentrations of overwintering Calanus finmarchicus were found in the eastern Lofoten Basin of the Norwegian Sea close to the shelf break in January 2001–2002. A coupled 3D hydrodynamic and ecological model was used to study the formation of this deep overwintering aggregation and its stability. The ecological model includes nutrients, phytoplankton and microzooplankton in addition to a stage-structured model of C. finmarchicus. Using a Eulerian approach, the model was initiated with an overwintering stock evenly distributed in the oceanic regions of the Norwegian Sea, i.e. where depths>600 m. Spawning and development of the new generation take place in response to vertical mixing and phytoplankton development. Animals are assumed to begin their descent to overwintering depths of 700–1000 m as late stage Vs. Model results show that, in late summer, high concentrations of animals were found at overwintering depths near the shelf break north of the North Sea, off the northeastern Vøring Plateau and in the eastern Lofoten Basin along the slope of the Barents Sea shelf. They remained there for months due to deep eddies and southward, deep currents along the Norwegian shelf. The simulation experiments indicate that the combined effect of deep anticyclonic circulation and vertical migration behavior of the animals may explain the high concentrations of overwintering C. finmarchicus found in field surveys in the Eastern Lofoten Basin, close to the shelf break.     

黄、渤海沿岸港湾的假潮及成因探讨

本文通过对日照港以北黄、渤海沿岸18个港湾8～27年假潮资料的分析,给出了不同区域港湾的假潮状况和成因.在该区域只有龙口港可时常发生100cm左右的大振幅假潮和＞150cm甚至＞300cm的特大振幅假潮,属假潮特别严重和唯一发生较大危害性假潮港湾;其余分属假潮相对较重、较轻和无假潮港湾,其假潮基本不具危害性或无危害性.分析结果表明其突然而剧烈的风场变化是导致各港湾假潮的直接原因,地理环境差异是造成港湾假潮强弱的关键因素;龙口港100cm左右和＞1 50cm的大和特大振幅假潮,是其特殊地理环境、港湾及附近大范围海域骤猛的向港爆发性大风,尤其强雷暴大风涌水在港内骤然积聚和海水惯性振荡的综合结果.     

A deep cyclonic gyre in the Australian–Antarctic Basin

The traditional image of ocean circulation between Australia and Antarctica is of a dominant belt of eastward flow, the Antarctic Circumpolar Current, with comparatively weak adjacent westward flows that provide anticyclonic circulation north and cyclonic circulation south of the Antarctic Circumpolar Current. This image mostly follows from geostrophic estimates from hydrography using a bottom level of no motion for the eastward flow regime which typically yield transports near 170 Sv. Net eastward transport of about 145 Sv for this region results from subtracting those westward flows. This estimate is compatible with the canonical 134 Sv through Drake Passage with augmentation from Indonesian Throughflow (around 10 Sv).A new image is developed from World Ocean Circulation Hydrographic Program sections I8S and I9S. These provide two quasi-meridional crossings of the South Australian Basin and the Australian–Antarctic Basin, with full hydrography and two independent direct-velocity measurements (shipboard and lowered acoustic Doppler current profilers). These velocity measurements indicate that the belt of eastward flow is much stronger, 271 ± 49 Sv, than previously estimated because of the presence of eastward barotropic flow. Substantial recirculations exist adjacent to the Antarctic Circumpolar Current: to the north a 38 ± 30 Sv anticyclonic gyre and to the south a 76 ± 26 Sv cyclonic gyre. The net flow between Australia and Antarctica is estimated as 157 ± 58 Sv, which falls within the expected net transport of 145 Sv.The 38 Sv anticyclonic gyre in the South Australian Basin involves the westward Flinders Current along southern Australia and a substantial 33 Sv Subantarctic Zone recirculation to its south. The cyclonic gyre in the Australian–Antarctic Basin has a substantial 76 Sv westward flow over the continental slope of Antarctica, and 48 ± 6 Sv northward-flowing western boundary current along the Kerguelen Plateau near 57°S. The cyclonic gyre only partially closes within the Australian–Antarctic Basin. It is estimated that 45 Sv bridges westward to the Weddell Gyre through the southern Princess Elizabeth Trough and returns through the northern Princess Elizabeth Trough and the Fawn Trough – where a substantial eastward 38 Sv current is hypothesized. There is evidence that the cyclonic gyre also projects eastward past the Balleny Islands to the Ross Gyre in the South Pacific.The western boundary current along Kerguelen Plateau collides with the Antarctic Circumpolar Current that enters the Australian–Antarctic Basin through the Kerguelen–St. Paul Island Passage, forming an energetic Crozet–Kerguelen Confluence. Strongest filaments in the meandering Crozet-Kerguelen Confluence reach 100 Sv. Dense water in the western boundary current intrudes beneath the densest water of the Antarctic Circumpolar Current; they intensely mix diapycnally to produce a high potential vorticity signal that extends eastward along the southern flank of the Southeast Indian Ridge. Dense water penetrates through the Ridge into the South Australian Basin. Two escape pathways are indicated, the Australian–Antarctic Discordance Zone near 125°E and the Geelvinck Fracture Zone near 85°E. Ultimately, the bottom water delivered to the South Australian Basin passes north to the Perth Basin west of Australia and east to the Tasman Basin.     

大连湾小孤山养殖海域富营养评价及牡蛎死因分析

根据大连湾小孤山养殖海域环境调查结果，评价了养殖海域环境现状，分析了牡蛎死亡的可能原因，讨论了预防牡蛎暴发性死亡的对策。