海南岛南渡江三角洲的废弃与侵蚀

讨论了海南岛南渡江三角洲由发展到废弃的演化过程,分析了不同废弃阶段的河口平面形态由东向西变化等特征,对比活动三角洲与废弃三角洲的显着地貌差异.此外还讨论了活动三角洲前缘潮流在岸外较深水区的侵蚀作用和泥沙的向东搬运,以及波浪在近岸较浅水区的侵蚀作用和泥沙的向西和向岸的搬运.     

从海南岛全新世孢粉研究看海滨红树林的演化

海南岛是我国第二大岛,位于18°09'～21°10'N,108°03'～110°03'E北隔琼州海峡与雷州半岛相望.海岸线长达1500km,全岛面积为33900km2,四周地形低,中南部山地耸立,海拔100m以下的台地、平原占全岛面积的近2/3.     

基于数据分析方法的有居民海岛分类评价研究

海岛是我国国土重要的组成部分,是具有特殊性质的独立地理单元。海岛进行分类评价对海岛的开发和保护意义重大。文章选择30个海岛,从环境保护、经济发展和社会发展3个方面建立16个指标,通过聚类分析、主坐标分析和主成分分析,对海岛进行分类,同时研究海岛不同指标之间的关系。研究发现,海岛可以分为经济发展型、环境发展型和传统发展型...     

A 2D-numerical modeling of the generation and propagation of internal solitary waves in the Luzon Strait

The wide presence of internal solitary waves (ISWs) in the northern South China Sea (SCS) has been confirmed by both Synthetic Aperture Radar (SAR) images and in situ observations. These ISWs are believed being generated over the varying topography in the Luzon Strait. They typically propagate westwards into the SCS with a diurnal or semidiurnal period. Their generation sites are, however, not yet solidly identified. To obtain a clear picture of the ISWs, we designed numerical experiments to analyze the generation and propagation of the ISWs in the Luzon Strait using a 2-dimensional non-hydrostatic model. The model current is forced by barotropic or baroclinic currents imposed at open boundaries. The experiments show that the tidal current serves as a kind of triggering force for the ISWs over the submarine ridges in the strait. Under the forcing of tidal currents, depressions are formed near the ridges. The ISWs then split from the depressions through a process different from lee-wave generation mechanism. The appearance of the ISWs is influenced by the strength and period of the forcing current:the ISWs are more likely to be generated by a stronger tidal current. That is why the ISWs in the Luzon Strait are frequently observed during spring tide. Compared with diurnal tidal current, the ISWs generated by semidiurnal tidal current with the same amplitude is much more energetic. It is partly because that the wave beams in diurnal frequency have a larger angle with the vertical direction, thus are more likely to be reflected by the topography slope. The impact of the Kuroshio to the ISWs is also analyzed by adding a vertical uniform or shear current at boundaries. A vertically uniform current may generate ISWs directly. On the other hand, a vertically shear current, which is more realistic to represent the Kuroshio branch, seems to have little influence on the generation process and radiating direction of the ISWs in the Luzon Strait.     

不同SST资料在海南岛和北部湾珊瑚白化预警中的适用性比较

近年来,受全球气候变化及极端天气的影响,全球范围频繁出现珊瑚礁白化现象,遥感SST已广泛应用于珊瑚白化的监测和预警中。海南岛近岸及北部湾海域的珊瑚礁近年也倍受白化压力,然而,遥感SST在海南岛近岸及北部湾海域珊瑚白化预警中的适用性尚不清楚。为此,本研究比较了3种常用的遥感SST数据(OISST、GHRSST和CoralTemp)在研究海域的异同及其在夏季珊瑚白化预警中的适用性。结果表明,GHRSST的SST最高、CoralTemp次之、OISST最低,OISST的偏差在2013年以前比较明显,GHRSST和CoralTemp在2003年之后比较接近;与浮标的现场观测值相比,2006—2020年CoralTemp的平均偏差和均方根误差分别为0.03℃和0.92℃,GHRSST为0.08℃和0.96℃,OISST为-0.25℃和1.21℃,CoralTemp在研究区域内更为准确;3种遥感SST计算的DHW与使用现场SST计算的趋势一致,CoralTemp的结果更为接近现场SST。因此,3种遥感SST资料中,CoralTemp相对来说更适用于研究海域。     

超强台风“灿都”(2021年)对黑潮入侵吕宋海峡的影响

探究台风“灿都”经过吕宋海峡附近时的海洋变化过程及其对黑潮入侵吕宋海峡的影响。基于涡尺度海洋再分析资料和中国气象局台风最佳路径数据,研究台风“灿都”经过吕宋海峡附近时海洋热力和动力结构的变化,及吕宋海峡输运对台风的响应。台风“灿都”经过菲律宾东部海域的次表层暖涡维持其强度并发展至巅峰阶段,沿途造成海温降低、海表高度降低、混合层加深等。台风位于吕宋海峡中线附近时,其右侧的暖涡与其发生相互作用,暖涡整体结构被打破。台风到达台湾岛东侧时,遇到其东侧的冷涡并使其加强,强化的负反馈机制使台风强度迅速减弱。在吕宋海峡附近,台风增强了从南海的输出流,抑制了黑潮向南海的入侵流。海峡剖面热能输送的变化与水体输运的变化较一致,而热含量的变化主要受到台风引起的输运异常的间接影响。中尺度涡旋在台风“灿都”发展过程中发挥着重要的作用,台风与暖涡的作用可能打破暖涡结构,与冷涡相遇则会使其加强。台风改变吕宋海峡输运结构主要是抑制中部入侵流和促进南侧输出流,激发出的海峡剖面上的输运异常波动在深层领先于浅层。     

2008年8—9月份吕宋海峡西南侧锚定ADCP的斜压海流观测

2008年8月份在吕宋海峡西侧大约4000m深的海域首次布放了两套深水潜标,对上层海洋进行了为期一个月的高频率ADCP海流采样。对数据进行了多重处理,分解得到平均流和逐层潮流,并分析了具有斜压性海流的频率分布。调和分析结果表明,该海域以不规则日周期潮流为主,潮流椭圆随深度旋转。海流的功率谱分析表明,内潮能量在温跃层附近最大,并随深度减小,同时海流有明显的近惯性振荡信号。该观测为了解吕宋海峡深层海洋的潮流、近惯性运动以及海峡水交换提供了第一手的资料。     

福建平潭岛的风沙地貌与海岸演变

在台湾海峡众多的海岛中,平潭岛以风大、沙多著称.风沙作用发生在2400a B.P.左右至今,风沙作用使该岛增加了90km^2的土地.本文论述的海岛东部风沙地貌系列受NNE优势风控制,是泥砂在风和水动力作用下复合搬运与沉积的产物,以堆积型为主,伴生侵蚀-刻蚀型.风沙在七里埔、苍海造就了约14km2的土地,在岛的中部建造了淡水湖泊“岚湖”,在田美沃留下了风蚀刻痕微地貌.此外,风沙活动还影响了海岛东部地区海岸沙滩的冲淤变化.平潭岛风沙地貌系列是台湾海峡一个独特的地质景观,其对海岸带环境变化的影响在中国东部极具代表性,在我国沿海风沙地层学和地貌学上均有较高的科研价值.     

芝罘岛北岸海湾砾滩侵蚀研究

对位于芝罘岛北岸婆婆口东侧海湾潮间带砾滩进行了研究,通过2004年5月和2007年5月2次野外调查结果分析,获得了2次采样时砾滩的特征及其空间的变化特征.调查统计表明,2004年5月的砾滩属于正常的砾滩,砾滩的结构较完整,发育2道滩脊;2007年5月的砾滩不完整,部分滩面基岩裸露.海滩砾石的形态特征统计,能反映海滩横剖面与纵剖面的变化.平均粒径38mm的等值线,在砾潍上呈现出随时间变化而向海的方向推移.由于砾石在3年中的磨损有限,砾石特征参数的空间变化主要是由于海洋异常动力变化,而促使砾石的组成及结构发生急剧调整的结果.海滩砾石调整事件可能与2007年3月的特大风暴潮有关.     

On generation source sites of internal waves in the Luzon Strait

This effort aims to determine the generation source sites in the Luzon Strait for energetic, long-crest, transbasin internal waves （IW） observed in the northern South China Sea （NSCS）. The roles of islands distributed on eastern side of the strait, Kuroshio, submarine ridges, shoaling thennocline, and strait configuration played in the IW generation are examined using the cruise data analysis, satellite data interpretation, and dynamical analysis. The islands and channels on eastern side of the strait are excluded from a list of possible IW source sites owing to their unmatched horizontal dimensions to the scale of IW crest line length, and the relative low Reynolds number. The Kuroshio has a potential to be a radiator for the long-crest IW disturbances, meanwhile, the Kurosbio west （east） wing absorbs the eastward （westward） propagating IW disturbance. Namely, the Kuroshio blockades the outside west-east propagating IW disturbances. The 3-D configuration of the Luzon Strait is characterized by a sudden, more than one order widening of the cross-section areas at the outlets on both sides, providing a favorable condition for IW type initial disturbance formation. In the Luzon Strait, the thermocline is featured by a westward shoaling all the year around, providing the dynamical conditions for the amplitude growth （declination） to the westward （eastward） propagating IW type disturbance. Thus, the west slope of western submarine ridge at the western outlet of the Luzon Strait is a high possibility source sites for energetic, long-crest, transbasin IWs in the NSCS. The interpretation results of satellite SAR images during a 13 a period from 1995 to 2007 provide the convincing evidence for the conclusions.