Numerical Simulation and Dynamical Analysis for Low Salinity Water Lens in the Expansion Area of the Changjiang Diluted Water

The low salinity water lenses（LSWLes） in the expansion area of the Changjiang diluted water（CDW） exist in a certain period of time in some years. The impact of realistic river runoff, ocean currents and weather conditions need to be taken into account in the dynamical analysis of LSWL, which is in need of research. In this paper, the POM-σ-z model is used to set up the numerical model for the expansion of the CDW. Then LSWL in summer 1977 is simulated, and its dynamic mechanism driven by wind, tide, river runoff and the Taiwan Warm Current is also analyzed. The simulated results indicate that the isolated LSWL detaches itself from the CDW near the river mouth, and then moves towards the northeast region outside the Changjiang Estuary. Its maintaining period is from July 26 to August 11. Its formation and development is mainly driven by two factors. One is the strong southeasterly wind lasting for ten days. The other is the vertical tidal mixing during the transition from neap tide to spring tide.

Study on Reduction of Mixed Water Salinity by Sound Wave <br/>—Toward Water Scarcity Issue-Solving in Isolated Islands in the World

There are so many Isolated Islands (inhabited islands) in the world, including Japan. However, at present islanders, there have been faced with the decline of industries, serious concerns of rapid aging and very low birthrate without children and water scarcity issues etc. It can be said that these situations are under the environment which shows a microcosm of Japanese and/or world survival society in the near future. In this paper, the experimental data on the reduction of the mixed water (seawater & rainwater) salinity by the sound wave when changing the volume ratio were first shown, taking into the characteristics of the Isolated Islands. Next, the main analysis result on the water qualities of mixed water with which sound wave was irradiated was shown and the consideration mainly based on the WHO drinking water quality standards was carried out. Finally, through a simple water quality improvement apparatus using small hydroelectric power, a consideration regarding a possibility of the purification of the water (to be a drinking water) based on the solar circulation energy (regenerative type’s natural energy) such as small hydropower utilization, natural sunlight utilization, natural gravity utilization, natural oscillation utilization has been described in the paper.

Influence of Kuroshio water on the distribution of dissolved oxygen in the northern East China Sea

On the basis of the four-cruise investigation data of the Kuroshio by the R/V "Xiangyanghong 09", this paper lays stress on the discussion of the relationship between the Kuroshio current systems, the distribution of dissolved oxygen in the northern East China Sea (ECS) and seasonal variations.

Simulation and analysis on seasonal variability of average salinity in the Yellow Sea

The CTD (conductivity, temperature and depth) data collected by six China-Korea joint cruises during 1996-1998 and the climatological data suggest that the seasonal variability of average salinity in the Yellow Sea (Sa) presents a general sinusoid pattern. To study the mechanism of the variability, annual cycles of Sa were simulated and a theoretical analysis based on the governing equations was reported.Three main factors are responsible for the variability: the Yellow Sea Warm Current (YSWC), the Changjiang (Yangtze) River diluted water (YRDW) and the evaporation minus precipitation (E-P). From December to the next May, the variability of Sa is mainly controlled by the salt transportation of the YSWC. But in early July,the YSWC is overtaken and replaced by the YRDW which then becomes the most important controller in summer. From late September to November, the E-P gradually took the lead. The mass exchange north of the37°N line is not significant.

Influence of a Flood Event on Salinity and Nutrients in the Changshan Archipelago Area (Northern Yellow Sea)

River discharge can deliver nutrients to the coastal zone and change the hydrologic properties of the water column. Soon after a flash flood from the Yalu River (Northeast China) in August 2010, we investigated the salinity and nutrient concentrations, as well as other environmental conditions in the Changshan Archipelago area, located approximately 100 km west of the river mouth in the northern Yellow Sea. Diluted water was mainly observed in the upper layers shallower than 15 m, with surface salinity between 18.13 and 30.44 in the eastern study area and between 28.16 and 29.72 in the western area. Surface salinity showed a significant negative correlation with concentrations of dissolved nutrients (P < 0.05), but not with that of Chlorophyll-a (Chl-a), dissolved oxygen (DO), particulate materials or pH. The average concentrations of nitrite, nitrate, and silicic acid decreased from the surface layer to bottom layer and were significantly higher in the east area than in the west area (P < 0.05). In contrast, average ammonium and phosphate concentrations were highest in the bottom layer of both areas, with no significant spatial differences. DO varied between 6.06 and 8.25 mg L-1 in the surface layer, and was significantly higher in the eastern area than in the western area in the surface and middle layers. Chl-a concentration was constantly below 4.09 μg L-1. Our work demonstrated the strong influences of Yalu River on proportions of various nutrient components in the Changshan Archipelago area. Silicic acid and total inorganic nitrogen levels were significantly elevated comparing to phosphate in the eastern area. Such changes can potentially induce phosphate limit to phytoplankton growth.

Impact of tropical cyclone Matmo on mixed zone of the Yellow and Bohai Seas

The Bohai Sea is a low-lying semi-enclosed sea area that is linked to the Yellow Sea via the Bohai straits(mixed zone). Its of fshore seabed is shallow, which makes it vulnerable to serious marine meteorological disasters associated with the northward passage of Pacific tropical cyclones. Analyses on data of remote sensing and buoy of the mixed zone of the Yellow and Bohai seas indicate that all the wind speed, significant wave height, and salinity(SAL) increased, sea surface temperature decreased, and wind energy density changed considerably during the passage of tropical cyclone Matmo on July 25, 2014. It was found that the SAL inversion layer in the mixed zone of the Yellow and Bohai Seas was caused by the tropical cyclone. Furthermore, it was found that the tropical cyclone transported the northern Yellow Sea cold water mass(NYSCWM) into the mixed zone of the Yellow and Bohai Seas. The NYSCWM has direct influence on both the aquaculture and the ecological environment of the region. Therefore, further research is needed to establish the mechanism behind the formation of the SAL inversion layer in the mixed zone, and to determine the influence of tropical cyclones on the NYSCWM.

漳州盆地水热系统的氢氧稳定同位素研究

本文对我国东南沿海地区温度最高的典型花岗岩裂隙热水盆地——漳州盆地水热系统的地下热水及各类相关的其它类型天然水的氢氧稳定同位素(δD和δ^(18)O)特征进行了研究。对漳州地区的大气降水线、地下热水起源、地下热水的补给源(区)以及影响地下热水同位素成分的形成与演化的海水与大气降水的混合等地球化学作用问题进行讨论。

长江口外羽状锋的屏障效应及其对水下三角洲塑造的影响

Based on data obtained from the survey of the Yangtze River Estuarine front, a detailed analysis of the frontal surface structure, position, intensity and seasonal variations is presented. From the frontal surface structure and water densities of both sides of the front, a formula of frontal surface barrier force is deduced based on the hydrostatic principle, which suggests the barrier effects of estuarine plume front. Furthermore, the correlation analysis between barrier effects and underwater topography indicates the plume front effects on the submerged delta development. That is, the average frontal surface position prevents the submerged delta from further extending eastward, the front movement with flood and ebb causes the submerged delta to slant eastward gently, and the seasonal variations of frontal intensity restricts the submerged delta cycle of summer deposition/winter erosion.

滨海盐碱地刺槐(Robinia pseudoacacia)混交林土壤水盐动态

以固氮树种刺槐与绒毛白蜡、榆树、臭椿三树种的混交林及其纯林为研究对象,研究了刺槐与不同树种混交对土壤水分、盐分年动态变化的影响。研究结果表明：（1）刺槐与3个树种混交,刺槐臭椿混交林生长最好,均高于各自纯林。（2）混交林一定程度改善了土壤含水量及层次分布,土壤含水量整体趋势均表现出0~60cm表层土中含水量高于各自纯林,而深层土壤含水量低的特点,只有8月份纯林和混交林的土壤含水量没有显著差别。不同树种在具体层次上略有差异;（3）混交林降低了土壤含盐量,改变了土壤盐分层次分布和年变化规律。不同月份间土壤含盐量随土壤深度、混交树种的变化而变化。深层土壤含盐量高,表层土壤含盐量低,混交林含盐量低于纯林且存在树种差异。混交林与纯林含盐量均雨季低,旱季高;但在某一具体月份各层次含盐量差别不大;不同土层含水量、含盐量与天然降水之间有明显的相关性,天然降水是混交林及纯林土壤水分的主要来源。

东海黑潮表层盐度分布特征及其影响因素

利用美国国家海洋大气管理局2007年发布的全球海域温、盐数据库资料,美国地球物理数据中心2006年发布的海底地形数据库资料以及日本海洋科学与技术机构2003年发布的1997—2002年东海地区月平均降水量资料,研究东海黑潮表层盐度的月季分布特征,并分析其影响因素。结果表明,东海黑潮表层盐度存在明显的月季变化特征。总体而言,12月至次年3月表层盐度高,6—9月表层盐度低,4、5月和10、11月为过渡阶段;表层盐度高值分布在东海黑潮主段靠近东边界一侧;6—9月入口段的表层盐度高于出口段的表层盐度,其他月份入口段的表层盐度低于出口段的表层盐度。东海黑潮表层盐度主要受表层温度、降水、径流的影响。冬、春、秋季的表层盐度分布在黑潮主段靠近陆架一侧区域受表层温度影响大;降水对东海黑潮表层盐度产生局部小范围的影响,时间主要集中在1月和6—8月份,区域分布在低纬25°N以南和30°N附近。长江冲淡水夏季对东海黑潮表层盐度的影响大于其他季节对东海黑潮表层盐度的影响,7月长江径流量达到最大值时,对应的黑潮扇形区的盐度最低。

用氢氧稳定同位素揭示闽江河口区河水、地下水和海水的相互作用

为了揭示闽江河口两岸的地下水形成演化规律以及河口区河水、地下水和海水的相互作用,分别于2009年枯水期(10至11月)和2010年丰水期(7至8月),在闽江河口区采集了河水、地下水和海水样品,测定了水样的氢氧稳定同位素组成和盐度。研究结果表明:(1)闽江河口两岸的浅层地下水主要接受降水补给,北岸地下水还接受山区基岩裂隙水补给,南岸浅层地下水在枯水期还接受经过蒸发作用的灌溉水补给;(2)闽江河口区,枯、丰水期河水与地下水的补排关系始终表现为地下水补给河水,枯水期南岸地下水在河口混合中的贡献明显增大;(3)海岸带含水层基本上不存在海水入侵,仅局部含水层有微弱的海水入侵迹象;(4)丰水期和枯水期的淡咸水混合带在河口中的位置和混合类型存在明显差异。

微咸水与再生水混灌对作物生理特性的影响

为了探讨淡水资源匮乏地区微咸水与再生水的安全合理利用,通过盆栽上海青试验,以清水灌溉为对照,设置再生水灌溉(T1)、微咸水—再生水1∶2灌溉(T2)、微咸水—再生水1∶1灌溉(T3)、微咸水灌溉(T4)4种灌溉方式,研究了不同比例微咸水与再生水混合灌溉对土壤水盐、作物生物量(地上部和地下部)、叶片叶绿素含量、可溶性蛋白含量、丙二醛(MDA)含量、过氧化氢酶(CAT)活性、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性的影响。结果表明:(1)上海青收获后,不同比例微咸水与再生水混合灌溉处理土壤含水率和含盐量较清水灌溉(CK)均有所升高,其中T1、T2、T3处理土壤含水率与CK差异不显著,T4处理土壤含水率较CK差异显著(P<0.05),而各处理土壤含盐量与CK均差异显著;与T1处理相比,随着灌溉水中微咸水比重的升高,土壤含水率逐渐升高,且至T4处理时差异显著。(2)微咸水与再生水混灌对上海青地上部鲜重有一定影响,而对地上部干重以及地下部生物量无显著影响。与T1相比,T2、T3、T4处理上海青地上部鲜重均显著降低(P<0.05),降幅为24.78%~26.36%,地上部干重亦均降低,但差异不显著,降幅为19.14%~24.54%,地下部鲜重和干重无显著性变化。(3)微咸水与再生水混灌对上海青生理指标(叶绿素含量、可溶性蛋白含量、MDA含量、POD活性、CAT活性)没有显著影响,对SOD活性具有显著的提升作用。与T1相比,T2、T3、T4处理叶绿素a含量分别降低4.98%,3.82%和9.26%,叶绿素b含量分别降低10.88%,8.20%和13.46%,叶绿素总量分别降低9.76%,6.12%和10.15%,CAT活性分别提高8.51%,8.51%和-19.15%,POD活性分别提高1.92%,17.24%和-2.87%,SOD活性分别提高104.07%,62.20%和41.67%。随着混合液中微咸水比重的升高,上海青可溶性蛋白含量先降低后升高,MDA含量先升高后降低。(4)基于第二代综合生物响应指数(integrated biological response version 2,IBR v2),综合考虑土壤水盐、作物生理指标以及再生水资源本身的局限性,在淡水资源匮乏地区利用微咸水灌溉时,可以考虑用再生水作为替代清水水源与微咸水配合使用,微咸水—再生水混灌比例以1∶1为宜。研究结果可为淡水不足地区利用微咸水(3 g/L)灌溉提供参考。

M_2分潮对夏季长江冲淡水扩展影响的数值研究

利用σ坐标系下的斜压浅海环流模式，研究M2分潮对夏季长江冲淡水扩展的影响。在“准定常流”作用下，模拟出能反映夏季长江冲淡水扩展的盐度场，并模拟出与黄、东海实测资料相符的M2分潮。在此基础上，用两种方案讨论M2分潮对冲淡水的影响。第一种方案，仅考虑M2分潮，计算它对冲淡水扩展的影响。第二种方案，将M2分潮和“准定常流”耦合，计算冲淡水扩展的变化。结果表明，从分潮对冲淡水扩展有一定影响，其中包括潮混合和定向输运。

西南季风不同阶段南海北部珠江口外断面水文调查分析

根据2000年7月及2001年5月南海北部珠江口外断面CTD调查资料、同期气象资料,并结合该海域历史资料,对调查断面珠江冲淡水扩展范围、跃层变动情况及上升流特征进行了分析,观察到对应于夏季西南季风的不同阶段,调查断面跃层分布与珠江冲淡水影响范围均发生明显变动,升降流的影响也呈现出不同特征:(1)西南季风较强时,断面陆架区上表层受冲淡水影响明显,海区的层化结构明显加强;(2)西南季风较强时,调查断面出现上升流和下降流。研究结果表明:(1)局地风应力与热通量的变化控制了调查断面跃层或混合层的温度和深度的变化,影响着珠江冲淡水的扩展范围,西南季风较强时珠江冲淡水扩展范围变大,调查断面跃层或混合层强度变大,深度变深;(2)夏季西南季风强时调查断面存在上升流,其形成机制为风产生的离岸水体Ekman输运的补偿效应,底地形的变化虽然也造成较弱的外海次表层水涌升,但可能只是加强了上升的速度或强度;(3)夏季西南季风强时调查断面上存在上升流区与下降流区毗邻的现象,下降流成因可能有二,一为近岸流和陆坡流呈相反方向运动形成弱的反气旋涡,二为“上升与下降因相互水体补充的需要而共生”。

湖相深水细粒物质的混合沉积作用探讨

沉积物的混合是自然界的普遍现象,湖盆中广泛发育的深水细粒沉积岩本身就是一类混积岩。以东营凹陷古近系沙河街组三段下亚段—沙河街组四段上亚段细粒沉积岩为研究对象,通过厘米级岩心观察描述、小型沉积构造解剖、岩石薄片观察、X射线衍射全岩矿物分析及微量元素测试等方法,研究细粒物质的产出状态和混合方式;分析湖盆流体、气候及水体性质对细粒物质迁移、混合、沉积的控制作用,尝试探讨细粒物质的混合沉积机制。结果表明,湖相深水细粒沉积岩既有物质成分上的混合,也有结构的混合,且在宏观与微观的不同尺度均存在混合;混合沉积作用有均匀混合、纹层叠置混合、不均匀团块状混合等类型。纹层叠置混合沉积是最主要的混合沉积方式,依据纹层接触关系、所占比例及矿物产出状态可分为泥砂—灰纹层叠置混合型、泥—灰纹层叠置混合型、泥砂粒序—灰纹层叠置混合型、灰—泥—云纹层叠置混合型等。湖相深水细粒物质的混合沉积作用类型多且往往受多个因素同时控制,气候及水动力条件是控制细粒混合沉积岩发育的最主要因素,不同流体(浊流和底流)作用下的细粒沉积物混合作用存在差异。气候引起湖水性质变化及水体分层,从而控制不同类型细粒物质的絮凝沉降及化学沉积。不同构造部位、不同水体深度的混合作用不同;相同构造部位在垂向上也存在混合沉积方式的差异。

2004年夏初、秋末长江口外海区冲淡水及羽状锋的盐度特征

用国家海洋局东海环境监测中心2004年夏初(6月)和秋末(11月)对长江口外海区现场观测资料,用Matlab计算机编程语言对观测资料进行质量控制、插值网格化,绘制研究海区盐度立体分布图,显示夏初、秋末两季的盐度分布特征。将2004年夏、秋两季长江口外海区冲淡水和羽状锋的分布与以往观测研究结果对比,可得:(1)长江口外海区冲淡水的盐度值主要在5—31之间,冲淡水前缘盐度锋面的盐度值为18—28;盐度值20—28的盐度锋面基本体现该海区羽状锋的特征及变化。(2)夏初长江口外海区冲淡水范围明显大于秋末,夏初该海区以冲淡水为主,秋末冲淡水的范围收缩,紧贴沿岸一带。相应地,夏初该海区羽状锋呈倾斜锋面,占据较大的海区;秋末则为垂直锋面,介于122.50°E—122.70°E海区。

强潮河口环境和生态需水及其计算方法

针对钱塘江河口以海域来沙为主的强潮河口特点,提出其环境和生态需水,包括维持河口冲淤平衡需水、防止河口咸水入侵需水、维持河口水功能区水质达标需水及最小生态需水。研究了各部分需水的计算方法,在一定计算条件下给出了定量的计算结果。根据分时段考虑原则、兼容性原则和区域性原则,对环境和生态需水的综合计算方法进行了探讨。研究表明,钱塘江河口环境和生态需水年总量主要由维持河口冲淤平衡需水决定,占多年平均来水量的80%,而年内不同时期需水的主要控制因素不同,并随计算条件发生转化。

长江口及其邻近海区环流和温、盐结构动力学研究Ⅳ盐度结构

盐度的数值模拟结果表明:一年四季长江口及其邻近海区的盐度分布均为近岸低,外海高,近岸与外海盐差大。冬季近岸和外海的上层盐度呈垂直均匀分布,陡坡及外海的底层出现层化;近岸特别是长江口及其以南近岸盐度的水平变化显著,外海变化缓慢。春季在长江口以北,近岸至外海的表层至近底层盐度呈垂直均匀分布,近岸至外海的底层存在一个向北延伸的盐舌;长江口及其以南近岸和外海的表层至次表层盐度呈垂直均匀分布,在近岸稍远的表层至次表层形成盐跃层,其强度自近岸至外海和自表层至底层逐渐减弱;在陡坡区的底层盐度几乎呈均匀分布,并保持高盐特征。夏季除长江口及其以南近岸浅水区盐度呈垂直均匀分布外,其它区域盐度均出现剧烈分层,在长江冲淡水区形成强盐跃层,其强度自表层至底层迅速减弱,陡坡至外海的底层盐度大致呈均匀分布且保持高盐特征。秋季长江口以北近岸浅水区表层盐度低且出现层化,表层以下盐度高且呈垂直均匀分布;近岸以远自表层至底层呈垂直均匀分布,在外海上层盐度低且呈垂直均匀分布,而底层盐度高并出现分层;长江口及其以南近岸浅水区盐度呈垂直均匀分布,陡坡区出现层化,其盐度为表层低,底层高;层化自表层至底层逐渐增强,并随陡坡至外海的减弱,上层又逐渐变为垂直均匀分布。

长江口外低盐水团发展的正压不稳定机制分析

针对长江冲淡水扩展区域低盐水团现象,开展正压不稳定机制研究。基于1977年夏季低盐水团的演变特征分析,将初始形成的低盐水团看成小扰动,建立小扰动方程描述低盐水团运动,采用WKBJ方法求解小扰动方程,讨论了快波过程(重力惯性波)和慢波过程(余流作用)对低盐水团的影响,并给出了受慢变波包影响的能量演变方程。研究表明,快波过程对低盐水团基本没影响,低盐水团从口门向口外东北海域运动过程中,由于水深加大,慢波过程有利于低盐水团发展。

潮致余流和潮混合对长江口外东北海域低盐水团的作用

长江冲淡水对黄海、东海水文环境有重要影响,它主要以羽状形态向外海扩展,在某些年份的特殊时间段也存在孤立的低盐水团现象。在低盐水团的动力机制研究中,风、径流量、台湾暖流、天文潮和斜压不稳定的作用已得到讨论。天文潮对冲淡水及低盐水团的影响主要包括潮致余流和潮混合,潮致余流作用仍缺乏讨论。本文对1983年8月低盐水团的动力机制进行数值模拟分析,重点讨论了潮致余流和潮混合的影响。结果表明:潮致Lagrange余流促使一部分冲淡水从口门向北输运,在32°N附近呈舌状转向东,有利于在口外东北海域形成低盐水团;小潮转大潮的垂向混合作用加强,浅水区表层盐度升高的速度快于较深水区,也有利于在口外东北海域形成低盐水团。