Possible Density Change of the Origin of North Pacific Intermediate Water Due to Double Diffusion in the Mixed Water Region     

Ryuichiro?InoueEmail author  Jiro?Yoshida 《Journal of Oceanography》2005,61(5):871-883

In this study we test Talley's hypothesis that Oyashio winter mixed-layer water (26.5–26.6σ _θ) increases its density to produce the North Pacific Intermediate Water (NPIW) salinity minimum (26.7– 26.8σ_θ) in the Mixed Water Region, assuming a combination of cabbeling and double diffusion. The possible density change of Oyashio winter mixed-layer water is discussed using an instantaneous ratio of the change of temperature and salinity along any particular intrusion (R _l ). We estimate the range of R _l ^DD required to convert Oyashio winter mixed-layer water to the NPIW salinity minimum due to double diffusion, and then assume double-diffusive intrusions as this conversion mechanism. A double-diffusive intrusion model is used to estimate R _l ^DD in a situation where salt fingering dominates vertical mixing, as well as to determine whether Oyashio winter mixed-layer water can become the NPIW salinity minimum. Possible density changes are estimated from the model R _l ^DD by assuming the amount of density change due to cabbeling. From these results, we conclude that Oyashio winter mixed-layer water contributes to a freshening of the lighter layer of the NPIW salinity minimum (around 26.70σ_θ) in the MWR.  相似文献   

印度洋东部金枪鱼延绳钓渔业研究--大眼金枪鱼(Thunnus obesus)的生物学特征   总被引：4，自引：0，他引：4  

叶振江  王艳君  高天翔 《中国海洋大学学报(自然科学版)》2003,33(3):343-348

根据作者在印度洋东部海域的延绳钓生产实践,对渔获的大眼金枪鱼群体的群体构成、摄食、繁殖等基本生物学特征进行了初步探讨.结果表明,渔获群体由纯重10～115kg、叉长80～195cm个体组成,纯重与叉长关系式w=2.000×10-5×L2.969;渔获物以3～5龄个体为主,雄性个体所占比例明显高于雌性个体,且随年龄增长雄性个体所占比例逐步提高.鱼群在该海域产卵期较长,不同年龄组性腺发育节律有明显差异.  相似文献   

气溶胶的光学厚度与反射率比的处理方法   总被引：2，自引：0，他引：2  

高飞 《海洋技术学报》2003,22(1):25-28

气溶胶光学厚度与气溶胶反射率比都是大气校正所需的重要大气参数，同时也是海洋水色卫星主要的数据产品，它们的测量精度将直接到卫星数据产品正演的精度和卫星数据产品的应用。文章在简述气溶胶光学厚度与气溶胶反射率比的基本测量原理和处理方法的基础上，结合多次试验数据结果进行简要的评价。  相似文献   

Paleoenvironment and sea-level change in the early Cretaceous Barents Sea—implications from near-shore marine sapropels     

Uwe?LangrockEmail author  Ruediger?Stein  Marcus?Lipinski  Hans-Jürgen?Brumsack 《Geo-Marine Letters》2003,23(1):34-42

The late Volgian (early "Boreal" Berriasian) sapropels of the Hekkingen Formation of the central Barents Sea show total organic carbon (TOC) contents from 3 to 36 wt%. The relationship between TOC content and sedimentation rate (SR), and the high Mo/Al ratios indicate deposition under oxygen-free bottom-water conditions, and suggest that preservation under anoxic conditions has largely contributed to the high accumulation of organic carbon. Hydrogen index values obtained from Rock-Eval pyrolysis are exceptionally high, and the organic matter is characterized by well-preserved type II kerogen. However, the occurrence of spores, freshwater algae, coal fragments, and charred land-plant remains strongly suggests proximity to land. Short-term oscillations, probably reflecting Milankovitch-type cyclicity, are superimposed on the long-term trend of constantly changing depositional conditions during most of the late Volgian. Progressively smaller amounts of terrestrial organic matter and larger amounts of marine organic matter upwards in the core section may have been caused by a continuous sea-level rise.  相似文献   

Evidence of NW extension of the North Anatolian Fault Zone in the Marmara Sea: a new interpretation of the Marmara Sea (Izmit) earthquake on 17 August 1999     

Erkan G?ka?an  Cem Gazio?lu  Bedri Alpar  Zeki Yücel  ?ükrü Ersoy  O?uz Gündo?du  Cenk Yalt?rak  Buser Tok 《Geo-Marine Letters》2002,21(4):183-199

Active faults aligning in NW–SE direction and forming flower structures of strike-slip faults were observed in shallow seismic data from the shelf offshore of Avcılar in the northern Marmara Sea. By following the parallel drainage pattern and scarps, these faults were traced as NW–SE-directed lineaments in the morphology of the northern onshore sector of the Marmara Sea (eastern Thrace Peninsula). Right-lateral displacements in two watersheds of drainage and on the coast of the Marmara Sea and Black Sea are associated with these lineaments. This right-lateral displacement along the course of these faults suggests a new, active strike-slip fault zone located at the NW extension of the northern boundary fault of the ?ınarcık Basin in the Marmara Sea. This new fault zone is interpreted as the NW extension of the northern branch of the North Anatolian Fault Zone (NAFZ), extending from the ?ınarcık Basin of the Marmara Sea to the Black Sea coast of the Thrace Peninsula, and passing through B üy ük ?ekmece and K ü ? ük ?ekmece lagoons. These data suggest that the rupture of the 17 August 1999 earthquake in the NAFZ may have extended through Avcılar. Indeed, Avcılar and İzmit, both located on the Marmara Sea coast along the rupture route, were strongly struck by the earthquake whereas the settlements between Avcılar and İzmit were much less affected. Therefore, this interpretation can explain the extraordinary damage in Avcılar, based on the newly discovered rupture of the NAFZ in the Marmara Sea. However, this suggestion needs to be confirmed by further seismological studies.  相似文献   

ODP与冲绳海槽海底热水活动研究   总被引：2，自引：1，他引：2  

高爱国 《海洋科学》1996,20(3):25-30

本文简要介绍了ＯＤＰ与海底热水活动研究，冲绳海槽中部现代海底热水活动区热水活动研究简况及其热水活动特征；就冲绳海槽中部热水活动研究中存在的问题与ＯＤＰ在冲绳海槽热水区钻探的科学目标进行了讨论。  相似文献   

太平洋西部3个岩芯沉积物的粒度组成及其天然湿容重和含水量的变化     

徐善民  周秀廷  高申禄  阎军 《海洋科学》1992,16(1):64-68

本文讨论了太平洋西部3个岩芯孔的粒度组成、天然湿容重和含水量的变化。沉积物组成以粉砂和粘土细粒为主,砂粒含量很少,而且多为有孔虫介壳。容重与沉积物粒度呈正相关,含水量则呈负相关。当粒度组成不变时,容重随岩芯埋藏深度的增加而增大,而含水量则减少。  相似文献   

海上平台桶形基础模型压力压贯与负压沉贯试验研究   总被引：1，自引：0，他引：1  

朱儒弟  何生厚 《海岸工程》1999,18(1):60-66

介绍了海上平台桶形基础模型（模型桶）压力压贯和负压沉贯的试验概况,对比分析了两者贯入力的巨大差异和产生的原因,给出了模型桶压力压贯中贯入深度与压力的关系,负压没贯负压与贯入深度,抽吸泵流量,基土渗流量,桶内土塞隆起之间的关系,试验结果表明,负压沉贯可以大大降低以砂质粉土为基土的土抗力,为在胜利油田类似基土海域海上平台应用桶形基础提供了试验依据,为海上现场导管架桶形基础平台的安装就位施工和控制提供了  相似文献   

绒螯蟹种质资源研究进展   总被引：1，自引：1，他引：1  

张秀梅  柳广东  高天翔 《中国海洋大学学报(自然科学版)》2002,32(4):533-542

本文综述了近年来有关绒螯蟹属在形态学、遗传学和育种学方面的研究进展 ,着重介绍了同工酶、RAPD和 mt DNA技术在绒螯蟹群体遗传学中的应用 ,提出遗传学分类标准的建立是绒螯蟹属分子分类的关键所在。  相似文献   

斑节对虾(Penaeus　monodon)蛋白质的氨基酸分析     

梁亚全  孙谧  韩阿寿  高淳仁 《海洋科学》1995,(3)

１９９３年分析了不同大小斑节对虾肌肉中游离氨基酸含量和肌肉蛋白质 的氨基酸组成。虾体肌肉中有各种游离氨基酸存在，但数量很少，而且比例与肌肉 中结合氨基酸不一致。不同大小斑节对虾，其肌肉中氨基酸组成基本一样，不同的 是小虾的半胱氨酸、蛋氨酸含量比中虾、成虾的低；成虾的缬氨酸、异亮氨酸含量比 小虾、中虾的低，而酪氨酸、苯丙氨酸、天门冬氨酸较高。随着虾体的长大，甘氨酸、 丙氨酸的含量逐渐下降，而脯氨酸的含量升高。雌雄虾的氨基酸组成基本一致，只 是雄虾的甘氨酸含量偏低，精氨酸含量偏高。  相似文献