南海海盆演变与深部海流

南海在距今34 Ma之前的始新世从陆地变为海洋,古水深不断加深,至距今24 Ma之前的中新世/渐新世之交,由于T60构造运动,南海海盆整体进入深海环境。但是,自中新世以来随着吕宋岛弧向欧亚板块碰撞,南海海盆的半封闭程度在距今10.0、6.5、3.0和1.2 Ma之前加剧,导致南海深部海水只能来自巴士海峡海槛深度2600 m以浅的太平洋。此后,巴士海峡两侧的南海与太平洋深部海水交换,由于全球海平面变化,呈现冰期/间冰期模式。     

Benthic foraminiferal fauna turnover at 2.1 Ma in the northern South China Sea

Quantitative analysis of benthic foraminifera from ODP Site 1146 in the northern South China Sea (SCS) shows that abundance of Bulimina alazanensis, sometimes up to about 90%, decreased gradually since 3.2 Ma, especially at 2.1 Ma. Abundance of other benthic foraminiferal species, Globobulimina sub-globosa and Cibicidoides wuellerstorfi, increased after 2.1 Ma. Comparison with changes in oxygen and carbon isotopes of planktonic and benthic foraminifera shows that high abundance values of B. alazanensis corresponded with lower values of oxygen isotope, but for carbon isotope, high values of the species were consistent with heavier carbon isotope of benthic foraminifera and lighter carbon isotope of planktonic foraminifera, respectively, and vice versa. Considering factors such as uplift of Bashi Strait, expansion of the North Hemisphere Glaciation, strengthening of East Asian winter mon-soon and variations in oxygen and carbon isotope of foraminifera, changes of B. alazanensis in ODP Site 1146 suggest that the source of deep water masses of the northern South China Sea changed from the warm Pacific deep water with high oxygen content to Pacific Intermediate water with low oxygen content at 2.1 Ma. In addition, the strengthened East Asian winter monsoon resulted in increased pri-mary productivity, high nutrient and suboxic bottom water. Variations in species of B. alazanensis seemed to be unable to tolerate environmental stress induced by deep water masses and productivity changes.     

南海中部浮游有孔虫通量的季节变化

南海中部１９９３－１９９５年连续两年的浅层和深层时间系列沉积捕获器试验,揭示游游有孔虫总通量以及Ｇlobigerinoides saculifer,Globigerinoides ruber,Neogloboquadrina dutertrei,Globigerinita glutinata等种的通量和相对百分数在东北季风和西南季风盛行期出现高值,而Globigerina bulloides,Pulleniatina obiquiloculata和Globorotalia menardii等种则仅在冬东北季风盛行期出现高值。此外,还发现浮游有孔虫属种的通量呈现明显的年际变化,研究表明这种季节和和年际变化主要受与东亚季风相关的表层初级生产力和海洋水文条件变化的控制。     

南海表面海温异常对南海季风影响的数值模拟

采用P-σ混合坐标系区域气候模式模拟了4－7月南海季风的爆发、演变过程，并进行了3组敏感性数值试验，研究南海表面海温异常对南海季风的影响，得到以下结论：（1）南海4月份海温异常对南海季风的爆发日期影响不大，但对季风爆发后的强度有所影响，异常增温造成南海季风增强，异常降温则南海季风减弱。（2）南海季风爆发和强度的变化与南海本身的海温变化情况有密切的关系，尤其是5月份南海海温异常。5月份南海异常增温可以使南海季风提前爆发，季风增强，南海海温异常降低时，南海季风爆发的时间推迟，季风减弱。（3）南海海温持续异常可以影响南海及中国大陆的高低空环流变化，海温持续异常增温可以使南海季风提前爆发，显地加强南海季风，并有利于南海季风向北推进，但当海温在6月份进一步持续增温时，则有利于季风维持在较南地区，阻碍季风向北发展；当海温持续异常降低时，南海季风推迟爆发，且明显减弱。     

三亚海洋环境试验站硅藻污损群落初探

【目的】探明海洋工程材料在热带海洋环境试验站硅藻污损群落的组成变化,为研究该海域材料腐蚀、生物污损以及生物多样性提供参考。【方法】取4种材料进行全浸腐蚀试验,定期取出试片冷藏客运到青岛,用次氯酸钠法制成永久封片,在带有微分干涉显微镜下记数,并使用PRIMER 6对硅藻Shannon多样性指数、Pielou’s均匀度指数和Simpson优势度进行计算。【结果】检出污损硅藻16目24科30属61种,其中双眉藻属、菱形藻属和舟形藻属为优势类群;物种多样性指数随时间而增加;热浸锌表面硅藻群落结构变化与其他3种材料有所不同。【结论】在南海热带近岸,材料表面性质对其表面附着的污损硅藻群落有一定影响,其中锌离子的影响较为明显。     

南海东部深海沉积物中孢粉与古环境研究

通过对南海东部294站深海柱状剖面高分辨孢粉、藻类的研究，将294站从下至上划分为7个孢粉组合带,依次为:Ⅰ带:Dacrydium-Pinus-Lithocarpus-Quercus(带绿)-Cyathea-Polypoldiace;Ⅱ带:Castanopsis-Lithocarpus-Dacrydium-Quercus(常绿)-Pinus-Polypodiace;Ⅲ带:Quercus(常绿)-Castanopsis-Podocarpus-Polypodiaceae;Ⅳ带:Polypodiaceae-Cyathea-Pteris-Pinus-Gramineae;Ⅴ带:Quercus(常绿)-Podocarpus-Lithocarpus-Cyathea-Polypodiaceae;Ⅵ带:Pinus-Quercus(常绿)-Palmae-Mangrove pollen-Gramineae;Ⅶ带:Dacrydium-Palmae-Mangrove Pollen-Pinus-Cyperaceae-Cyathea.并相应恢复了南海东部地区12万年以来5个植被、气候演替阶段，依次为：炎热、湿润的热带季雨林——暖热而稍干的热带北缘半常绿季雨林——炎热、湿润的热带季雨林——暖热而稍干的热带北缘半常绿季雨林——炎热、湿润的热带季雨林。结合氧同位素测年资料，对294站地层时代划分作了讨论，为南海古气候、古环境演变研究提供了科学的证据。     

华南前汛期区域持续性暴雨的分布特征及分型

利用广东和广西两省共175个台站的日降水观测资料,采用计算机检索的方法,对1961-2005年间华南前汛期区域持续性暴雨进行了定义。对南海夏季风爆发前后区域持续性暴雨的气候分布特征的分析发现,季风爆发前持续性暴雨频数从60年代至今呈现出正态分布的年代际变化特征,而季风爆发后的区域持续性暴雨频数变化则几乎相反;广东省前汛期区域持续性暴雨降水明显比广西强。此外,通过EOF方法和相关分析得到了夏季风爆发前后出现频率较高的几种分布雨型,它们能较好地代表季风爆发前后华南降水分布的特点。     

东亚夏季风系统和南海台风活动的关系

本文用1981,1982年6—9月东亚与澳大利亚部份测站的常规资料作诊断分析,探讨东亚夏季风系统各主要成员与南海台风活动的关系.结果得到,澳大利亚冷高压加强,105°E附近的越赤道气流跟着增强,南海的ITCZ发展,南海台风生成于澳大利亚冷高压高峰后的衰减时段.西南季风气流是南海台风的重要能量输送带。南支高空东风急流的增强与北支东风急流的动量下传,有利于南海台风生成.西太平洋气旋波移入南海促使南海低压生成.     

南海问题中的日本因素与我国的安全环境

冷战期间日本承认中国对南海的主权,冷战后日本追随美国开始介入南海争端。新世纪,为维护其海上“生命线”安全的需要,保障其经济利益,争夺地区主导权并在钓鱼岛的主权问题和东海划界问题上牵制中国,日本开始介入南海争端,其战略措施有：舆论炒作“中国威胁论”;加强与亚太国家的合作并进一步巩固日美同盟,包括拉拢东南亚国家联盟、建立日越战略合作伙伴关系、加强与印度尼西亚和菲律宾的战略关系;从军事战略上谋划介入南海地区。日本介入南海争端意图推动南海问题的国际化,增加问题解决的难度,阻遏中国走向海洋的步伐,严重地威胁中国领海主权的完整。在解决南海争端的过程中,如何平衡日本因素是中国面临的一大挑战。     

南海夏季风活动激发的大气遥相关型

北半球夏季,南海地区是全球大气热状况变化最为激烈的区域之一,而南海夏季风则是该地区最为活跃的天气事件,它的演变必将导致其它地区大气环流的响应．通过相关计算、合成分析等手段,揭示与南海夏季风活动相关联的北半球大气遥相关型的存在．该波列状的遥相关型与东亚地区相连,经北太平洋延伸至北美西岸．最高的相关位于西太平洋副热带高压区域,因而它可能对我国旱涝天气产生重要影响．     

黑潮对中国近海热盐输运的季节和年际变化

应用垂向混合坐标系海洋模式（HYCOM）,对赤道以及北太平洋进行了气候态模拟和1990-1999年的模拟.给出了黑潮对我国近海热量和盐量输运的定量结果,并对其季节和年际变化特征进行了分析.气候态模拟的结果表明,黑潮对东海的热量输运与该区域的海表面热通量同量级,且呈反向变化,热量输运冬季最大,夏季最小,7月为-9×1013W,2月为2.5×1014W,春、秋为过渡季节.黑潮向南海输运的热量除夏季为负值外,其它季节均为正值.黑潮年均向东海输运热量1.67×1014 W,向南海输运热量1.5×1014W.盐量输运的变化趋势与热量一致.对1990-1999年的模拟结果进行小波分析表明,黑潮对东海热量和盐量输运具有4~7年的显著周期,且与厄尔尼诺现象密切相关.厄尔尼诺年,黑潮向东海输运的热量和盐量均有明显减小.黑潮对南海热量和盐量输运的周期约为3~4年.黑潮对南海的热量输运也与厄尔尼诺现象存在负相关关系.     

Characteristics of hydrocarbon accumulation and exploration potential of the northern South China Sea deepwater basins

Although the huge potential of the northern South China Sea deepwater basins has been proven by a series of discoveries that followed the exploration breakthrough of well LW 3-1-1, recent drilling and other studies have demonstrated the uniqueness and complicated nature of hydrocarbon accumulations of the deepwater basins there. Based on a review of previous work and the latest exploration activities and studies, the purpose of this paper is to discuss the critical controls for hydrocarbon accumulations in the deepwater basins of the northern South China Sea. A terrestrial-marine transitional coal-bearing source rock is proposed to be the primary source rock for the deepwater basins. A marine source rock, which was first identified as contributing to hydro-carbon generation in this region, probably plays a significant role in the deep-and ultra-deep water basins south to the Pearl River Mouth and Qingdongnan basins. The shelf margin delta depositional systems in the Baiyun Sag, sourced from the Pearl River, are currently primary exploration targets in the deepwater part of the Pearl River Mouth Basin, whereas the western Red River delta-ic-submarine fan depositional systems, initially proven by drilling, are the possible major exploration reservoirs in the Qing-dongnan deepwater areas. Current deepwater exploration targets at the large-sized structural traps and deep and ultra-deep areas in the south of the Pearl River Mouth and Qingdongnan basins will be the future exploration focus. Deepwater exploration activities and relevant fundamental studies, supporting and promoting each other, are of great importance to the national energy supply of China, the basic regional studies of the South China Sea, advancements in technology, and development of related deepwater industries, and will safeguard national sovereignty and territorial integrity.     

Simulation or meridional overturning in the upper layer of the South China Sea with an idealized bottom topography

The large-scale upper circulations and meridional overturning in the upper layer of the South China Sea (SCS) with idealized bottom topography in winter and summer are investigated. Simulations with the GFDL general circulation model are carried out under the conditions of open or enclosed boundary regarding transport in the Luzon Strait. The intrusion area of Kuroshio, its impact on the meridional overturning in the upper layer of the SCS and seasonal characteristic of this impact are explored, respectively. The model is forced by climatological wind stress and relaxed to monthly mean climatological temperature and salinity. The resultant meridional overturning is non-enclosed, wit htransporting from north to south in the surface and returning to north at the depth of about 500 m in winter, about 200 m in summer, with amplitudes of 10^5 m^3/s. It shows the transporting path of intermediate water of the SCS and offers an idealized reference for further study on dynamics of wind-driven and thermohaline circulation of the SCS.