南海南部近50万年来沉积物特点及古环境意义

对南海南部MD05-2897孔沉积物的分析显示,该孔涵盖氧同位素1~12期,底界年龄约为50万年。碳酸钙含量曲线形态基本与底栖有孔虫氧同位素曲线平行,即碳酸钙高值对应氧同位素轻值,呈现典型的大西洋型碳酸钙分布模式。碳酸钙含量在冰消期的高值出现及含量变化均领先于氧同位素,证明低纬海区"碳酸钙泵"对大气二氧化碳浓度和温度的作用。粒度分析显示,3~5μm组分含量曲线的变化与氧同位素曲线基本平行,说明它主要受海平面升降变化控制,可作为海平面变化的间接指标。而1.5~2.5μm粒级颗粒主要通过河流的悬浮搬运,直接受亚洲夏季风及其所带来降雨的影响,可间接反映夏季风的强弱变化。南海南部深海沉积中的季风记录具有0.1 Ma偏心率周期,40 ka斜率周期,20 ka岁差和10 ka半岁差周期等丰富的频谱,显示出低纬度海区气候变化对轨道周期的良好响应。     

Crustal Structures of the Northernmost South China Sea: Seismic Reflection and Gravity Modeling

The South China Sea (SCS) is a marginal sea off shore Southeast Asia. Based on magnetic study, oceanic crust has been suggested in the northernmost SCS. However, the crustal structure of the northernmost SCS was poorly known. To elaborate the crustal structures in the northernmost SCS and off southwest Taiwan, we have analyzed 20 multi-channel seismic profiles of the region. We have also performed gravity modeling to understand the Moho depth variation. The volcanic basement deepens southeastwards while the Moho depth shoals southeastwards. Except for the continental margin, the northernmost SCS can be divided into three tectonic regions: the disturbed and undisturbed oceanic crust (8–12 km thick) in the southwest, a trapped oceanic crust (8 km thick) between the Luzon-Ryukyu Transform Plate Boundary (LRTPB) and Formosa Canyon, and the area to the north of the Formosa Canyon which has the thickest sediments. Instead of faulting, the sediments across the LRTPB have only displayed differential subsidence offset of about 0.5–1 s in the northeast side, indicating that the LRTPB is no longer active. The gravity modeling has shown a relatively thin crust beneath the LRTPB, demonstrating the sheared zone character along the LRTPB. However, probably because of post-spreading volcanism, only the transtension-shearing phenomenon of volcanic basement in the northwest and southeast ends of the LRTPB can be observed. These two basement-fractured sites coincide with low gravity anomalies. Intensive erosion has prevailed over the whole channel of the Formosa Canyon.     

Comparison among four kinds of data of sea surface wind stress in the South China Sea

By using remote sensing (ERS) data, FSU data, COADS data and Hellerman & Rosen-stein objective analysis data to analyze the sea surface wind stress in the South China Sea, it is found that the remote sensing data have higher resolution and more reasonable values. Therefore we suggest that remote sensing data be chosen in the study of climatological features of sea surface wind stress and its seasonal variability in the South China Sea, especially in the study of small and middle scale eddies.     

渤、黄、东海夏季环流的三维斜压模型

基于拉格朗日时均观点描述环流，建立起潮流与准定常流共同占优势系统中的陆浅海环流模型，并诊断计算了夏季渤、黄、东海的三维环流图。模拟结果较好地再现了渤、黄、东海主要流系的特征。对照冬季结果，对渤、黄、东海环流的季节变化做了阐述。从环流垂向分量的分布图上，可发现渐闽近海、长江口外存在较明显的上升流区。另外，对夏季渤、黄、东海的热盐环流和潮致余流分别进行了模拟，发现它们均能在黄海构成一逆时针向的五流系统，这对形成和维持夏季黄海冷水团的存在有重要作用。热盐环流的模拟结果表明，黄海冷水团环流含有“热成流”的成分；通过Lagrange余流的计算发现环绕黄河冷水团的环流还含有“潮成流”的成分。     

南沙群岛海域水体漫衰减系数Kd(490)的特性研究

对南沙群岛海区水体Kd(490）的特性进行了深入分析和探讨,研究结果表明：Kd（490）的垂直分布与同步测量的海水叶绿素a浓度的垂直分布有很强的相关性;Kd（490）的垂直分布反映出该区域海水存在较强的分层现象,研究中还发现上行辐亮度漫衰减系数KL（490）与Kd（490）垂直变化趋势相当一致,但是以二者达到最大值的深度为界,上层水体的KL（490）值稍大于Kd(490）值,在这一深度以下则相反。     

非线性共轭梯度法在东海黑潮流计算中的应用

基于现有的几种海流计算方法,根据与P矢量法相同的动力特性和内在假设,对海流计算提出了一种简单、高效、易扩展、适用范围广的新方法:非线性共轭梯度法.利用1989年4月以来的"中日黑潮合作调查研究"6个航次的CTD资料,对东海黑潮流区域应用非线性共轭梯度法进行了海流计算.通过与船载ADCP实测结果比较表明,非线性共轭梯度法是可行的.     

北方地区秋季日本对虾室内高密度精养的试验

为充分利用每年的8月以后直到翌年3月份都处于休闲状态的育苗场设施资源，笔者于1999年8月在河北黄骅进行日本对虾室内高密度精养的试验。在水温23－28℃、盐度28－32下，8月27日放苗，11月24日收成，养殖时间87d，单位水体产量平均为0．818kg/m^3，平均存活率为50．1％，旬生长率平均为0．75cm，成虾体长平均8cm，饵料系数为2．51，投入与产出比为2．5，平均单位水体创利63．83元／m^3，其结果说明本养殖模式不仅是可行的，而且具有利用率和效益高、实用性强的优点。本文还就相关问题进行了讨论。     

南海晚第四纪硅藻遗体及其地质意义Ⅵ.硅藻的2个新种和7个新记录

本文记述了南海晚第四纪沉积物中发现的两个新种[线形辐环藻（Actinocyclus lineatus Liu,Cheng et Lan sp.nov.）、星圆筛藻（Coscinodiscus aster-aeus Cheng,Liu et Lan sp.nov.）]以及在我国首次记录的圆筛藻的7个种。     

南海晚第四纪硅藻遗体及其地质意义：Ⅷ.几个问题的讨论

本文根据分析结果阐述了两种不同样品处理方法所获得的硅藻丰度和微型硅藻的人主要种类和相对百分含量。研究表明洗涤富集法所获得的硅藻丰度存在较大误差；微型硅藻的含量普遍介于１０％－２０％之间，最高可达４２．３１％，最低为５．６６％，并指出了在微型硅藻相对含量大于２０％的样品中 ，其主要种类为具槽直链藻和条纹小环藻等沿岸底格格不入中，并成群体产出。     

Circulations east of Taiwan and in East China Sea and east of Ryukyu Islands during early summer 1985

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