Mean flow and variability in the southwestern East Sea     

Kyung-Il Chang  Nelson G. Hogg  Moon-Sik Suk  Sang-Kyung Byun  Young-Gyu Kim  Kuh Kim 《Deep Sea Research Part I: Oceanographic Research Papers》2002,49(12)

The Ulleung Basin is one of three deep basins that are contained within the East/Japan Sea. Current meter moorings have been maintained in this basin beginning in 1996. The data from these moorings are used to investigate the mean circulation pattern, variability of deep flows, and volume transports of major water masses in the Ulleung Basin with supporting hydrographic data and help from a high-resolution numerical model. The bottom water within the Ulleung Basin, which must enter through a constricted passage from the north, is found to circulate cyclonically—a pattern that seems prevalent throughout the East Sea. A strong current of about 6 cms⁻¹ on average flows southward over the continental slope off the Korean coast underlying the northward East Korean Warm Current as part of the mean abyssal cyclonic circulation. Volume transports of the northward East Korean Warm Current, and southward flowing East Sea Intermediate Water and East Sea Proper Water are estimated to be 1.4 Sv (1 Sv=10⁻⁶ m³ s⁻¹), 0.8 Sv, and 3.0–4.0 Sv, respectively. Deep flow variability involves a wide range of time scales with no apparent seasonal variations, whereas the deep currents in the northern East Sea are known to be strongly seasonal.  相似文献   

赤潮叉角藻18SrDNA和ITS区序列测定与分析   总被引：20，自引：0，他引：20  

庄丽  陈月琴  李钦亮  屈良鹄 《海洋与湖沼》2001,32(2):148-154

采用PCR及克隆测序的方法，对1998年引发渤海赤潮的叉角藻18SrRNAadldey DNAITS区（Internal Transcribed Spacer Regions)进行了序列测定与分析。并通过因特网从国际分子生物学数据库中获取甲藻另外15个种的18rDNA序列，以Tetrahymena corlissi作为类群，分别采用Neighbor-Joining和Fitch方法构建甲藻较为一致和可靠的进化树图，探讨具有高度多样性和在分类上争议较多的甲藻各类群之间的形态与分子进化关系。结果表明，Prorocentrum(有2个简单的壳板）出现得较早，而大多数多甲藻目（覆盖着多个壳板）、裸甲藻目（大多数不具壳板）和膝沟藻目的成员较晚出现。另外，对叉角藻ITS区的分析表明，ITS区为高变区，是良好的分子标记，可用于叉角藻快速鉴定的专一性核酸分子探针的研制。  相似文献   

用Matlab中的Neural Network Toolbox仿真赤道东太平洋SST的预报模型   总被引：2，自引：0，他引：2  

张韧  蒋国荣  李妍 《海洋科学》2001,25(2):38-42

基于ＮＣＥＰ／ＮＣＡＲ再分析资料和ＣＯＡＤＳ海洋资料中的全球月平均海平面气压场、８５０hPa纬向风场及海洋温度场，利用Ｍatlab中的Ｎeural Network Toolbox仿真环境和ＢＰ模型改进算法比较准确地仿真和反演出了南方涛动指数、赤道纬向风指数和滞后的赤道东太平洋海温之间的动力结构和预报模型。该模型具有很好的拟合精度和可行的预报效果。可在一定时效内预测赤道东太平洋月平均海温的变化趋势。由于所建系统是具有直接因果关系的预报模型，因此不仅可直接用于预测，而且可有效避免类拟非线性微分方程组在积分过程中由于对初值敏感性而可能产生的对预报结果的不确定性。  相似文献   

运用德尔菲调查—灰色统计法确立水库鱼产力综合评价中的指标权重体系   总被引：1，自引：0，他引：1  

焦念志 《海洋湖沼通报》1992,(4)

本文运用德尔菲方法对水库鱼产力综合评价中指标权重的合理分配问题作了专家调查,并采用灰色统计法对调查结果进行归纳处理,从而确立了一个水库鱼产力影响因素诸层次各方面的评价指标权重体系,可供今后的评价工作参考使用。  相似文献   

华贵栉孔扇贝三倍体的研究   总被引：2，自引：1，他引：2  

曾志南  陈木等 《台湾海峡》1995,14(2):155-162

本文报道了用细胞松驰素B、高温和低温休克等方法诱导华贵栉孔扇贝（Chlamys nobilis）三倍体的实验结果。在26.0～28.0℃条件下，选用不同浓度的细胞松驰素B0.1、0.3、0.5、0.7和1.0mg/dm^3，在受精后15min，处理受精卵15min，三倍体诱导率分别为12.5%、37.5%、68.0%、66.6%和81.0%，其中0.5～1.0mg/dm^3浓度的细胞松驰素B对改变倍性最有效。高温休克选用31.0、33.0、35.0和37.0℃处理受精卵，最高三倍体诱导率达46.7%（33.0℃,处理15min）。低温休克选用6.0、8.0、10.0和12.0℃处理受精卵，最高三倍体诱导率为40.7%（10.0℃，处理20min）。实验结果表明，随着处理强度的增大和处理时间的延长，三倍体诱导率增高、但孵化率下降，畸型率上升。用高温休克处理的实验组幼虫生长速度较对照组快。作者认为，在商业性生产中，温度休克是诱导扇贝三倍体的一种简便、有效的方法。文中还就细胞松驰素B与温度休克诱导三倍体的机制进行了讨论。  相似文献   

Circulation and currents in the southwestern East/Japan Sea: Overview and review     

K.-I. Chang  W.J. Teague  S.J. Lyu  H.T. Perkins  D.-K. Lee  D.R. Watts  Y.-B. Kim  D.A. Mitchell  C.M. Lee  K. Kim 《Progress in Oceanography》2004,61(2-4):105

A review is made of circulation and currents in the southwestern East/Japan Sea (the Ulleung Basin), and the Korea/Tsushima Strait which is a unique conduit for surface inflow into the Ulleung Basin. The review particularly concentrates on describing some preliminary results from recent extensive measurements made after 1996. Mean flow patterns are different in the upstream and downstream regions of the Korea/Tsushima Strait. A high velocity core occurs in the mid-section in the upstream region, and splits into two cores hugging the coasts of Korea and Japan, the downstream region, after passing around Tsushima Island located in the middle of the strait. Four-year mean transport into the East/Japan Sea through the Korea/Tsushima Strait based on submarine cable data calibrated by direct observations is 2.4 Sv (1 Sv = 10⁶ m³ s⁻¹). A wide range of variability occurs for the subtidal transport variation from subinertial (2–10 days) to interannual scales. While the subinertial variability is shown to arise from the atmospheric pressure disturbances, the longer period variation has been poorly understood.Mean upper circulation of the Ulleung Basin is characterized by the northward flowing East Korean Warm Current along the east coast of Korea and its meander eastward after the separation from the coast, the Offshore Branch along the coast of Japan, and the anticyclonic Ulleung Warm Eddy that forms from a meander of the East Korean Warm Current. Continuous acoustic travel-time measurements between June 1999 and June 2001 suggest five quasi-stable upper circulation patterns that persist for about 3–5 months with transitions between successive patterns occurring in a few months or days. Disappearance of the East Korean Warm Current is triggered by merging the Dok Cold Eddy, originating from the pinching-off of the meander trough, with the coastal cold water carried Southward by the North Korean Cold Current. The Ulleung Warm Eddy persisted for about 20 months in the middle of the Ulleung Basin with changes in its position and spatial scale associated with strengthening and weakening of the transport through the Korea/Tsushima Strait. The variability of upper circulation is partly related to the transport variation through the Korea/Tsushima Strait. Movements of the coastal cold water and the instability of the polar front also appear to be important factors affecting the variability.Deep circulation in the Ulleung Basin is primarily cyclonic and commonly consists of one or more cyclonic cells, and an anticyclonic cell centered near Ulleung Island. The cyclonic circulation is conjectured to be driven by a net inflow through the Ulleung Interplain Gap, which serves as a conduit for the exchange of deep waters between the Japan Basin in the northern East Sea and the Ulleung Basin. Deep currents are characterized by a short correlation scale and the predominance of mesoscale variability with periods of 20–40 days. Seasonality of deep currents is indistinct, and the coupling of upper and deep circulation has not been clarified yet.  相似文献   

青藏高原中部湖泊沉积物中Zr/Rb值及其环境意义   总被引：14，自引：1，他引：14  

陈诗越  王苏民  金章东  沈吉 《海洋地质与第四纪地质》2003,23(4):35-38

由于青藏高原及其周边地区构造复杂,湖泊沉积物中的粒级差别很大,单一的测量方法往往难以奏效。Rb、Zr是表生地球化学过程中的稳定元素,但它们之间也存在显著差别,Rb一般富集在细颗粒中,Zr则在粗颗粒中含量较高。研究发现,湖泊沉积物中Zr/Rb比值与粘土(<2μm)含量存在显著相关,Zr/Rb值反映了湖泊沉积物的粒度大小。Zr/Rb比值所揭示的青藏高原中部280万年来经历的3次大的环境演化过程与岩性变化、孢粉指标反映的环境特征是一致的。  相似文献   

Biogeochemical Variation in Dimethylsulfide, Phytoplankton Pigments and Heterotrophic Bacterial Production in the Subarctic North Pacific during Summer     

Kazushi Aranami  Shuichi Watanabe  Shizuo Tsunogai  Masato Hayashi  Ken Furuya  Toshi Nagata 《Journal of Oceanography》2001,57(3):315-322

Dimethylsulfide (DMS), chlorophyll a (Chl-a), accessory pigments (fucoxanthin, peridinin and 19-hexanoyloxyfucoxanthin), and bacterial production (BP) were measured in the surface layer (0–100 m) of the subarctic North Pacific, including the Bering Sea, during summer (14 July–5 September, 1997). In surface sewater, the concentrations of DMS and Chl-a varied widely from 1.3 to 13.2 nM (5.1 ± 3.0 nM, mean ± S.D., n = 48) and from 0.1 to 2.4 µg L^–1 (0.6 ± 0.6 µg L^–1, n = 24), respectively. In the subarctic North Pacific, DMS to Chl-a ratios (DMS/Chl-a) were higher on the eastern side than the western side (p < 0.0001). Below the euphotic zone, DMS/Chl-a ratios were law and the correlation between DMS and Chl-a was relatively strong (r ² = 0.700, n = 27, p < 0.0001). In the euphotic zone, DMS/Chl-a ratios were higher and the correlation between DMS and Chl-a was weak (r ² = 0.128, n = 50, p = 0.01). The wide variation in DMS/Chl-a ratios would be at least partially explained by the geographic variation in the taxonomic composition of phytoplankton, because of the negative correlation between DMS/Chl-a and fucoxanthin-to-Chl-a ratios (Fuc/Chl-a) (r ² = 0.476, n = 26, p = 0.0001). Furthermore, there was a positive correlation between DMS and BP (r ² = 0.380, n = 19, p = 0.005). This suggests that BP did not represent DMS and dimethylsulfoniopropionate (DMSP) removal by bacterial consumption but rather DMSP degradation to DMS by bacterial enzyme.  相似文献   

伪卫星关键技术分析     

毛悦  孙付平 《海洋测绘》2006,26(2):69-72

对伪卫星实际应用中所面临的几项关键技术进行了论述,并重点研究了伪卫星空中基站的自身定位问题。从陆地上空伪卫星和海上伪卫星两个方面进行了仿真计算,分析了其几何精度因子随定位星座布局变化的规律,设计了最终的定位方案。  相似文献   

一种高效率的软件开发方法--以用户为中心的软件开发方法(UCD)     

郑蕾 《海洋技术学报》2006,25(1):54-57

软件开发是海洋监测技术与设备研究与开发的一个重要的环节,软件开发质量的高低直接关系到海洋监测仪器和设备的质量。文中阐释了以用户为中心的软件开发方法的概念、特点以及其实施中的基本原则和关键活动,并对传统的软件开发方法和以用户为中心的软件开发方法进行了比较研究。该方法不仅提高了用户的生产效率和生产质量,而且还减少了企业支持和培训方面的费用,提高了产品和服务的竞争力。  相似文献