基于长期观测的辽东湾口东部海域水动力特征研究

辽东湾口东部海域是辽东湾与渤海中部进行物质和能量交换的主要通道之一。本文利用坐底式海床基平台获取的近8个月的水动力连续观测资料,通过谱分析和调和分析方法对该海域的潮汐、潮流特征进行分析,并讨论了余流及底层温度的季节变化规律。研究结果表明:该海域潮汐属于不规则半日潮,平均潮差为0.95 m,最大可能潮差为2.27 m。潮流属于不规则半日潮流,M₂分潮流为其优势分潮流。主要分潮流运动形式为往复流,最大流速方向为西南-东北向。余流的季节性特征较为明显:秋季,余流流速在中层达到最大,流向以西南向为主;冬季,余流流速垂向变化较小,并呈西南偏西向流动;春季,流速随深度增加而减小,流向从表层至底层呈现逆时针旋转的特征。受底层潮流、水平温度梯度及海面温度日变化的影响,底层温度表现出短期的高频变化特征:秋季,短期振荡以半日周期信号为主;冬季,全日周期信号较为显著;春季,短期振荡的现象较弱。     

海洋上层暖水在热带气旋迅速增强中的作用:基于台风威马逊(1409)的个例研究

在登陆海南岛之前,台风威马逊在南海北部从热带风暴级别迅速增强成为超强台风。观测数据的分析结果显示,海洋上层的异常暖水在威马逊的迅速增强过程中扮演了重要的角色。威马逊期间,南海北部的海表面温度相比于气候态海表面温度暖很多。这部分异常暖水为威马逊提供了更多的能量,从而导致了威马逊的迅速增强。数值模拟结果进一步证明,南海北部的暖水在台风威马逊的迅速增强过程中起重要作用。如果没有这团异常暖水的影响,威马逊只增强25 hPa,仅为有暖水影响条件下增强程度的58.1%。     

2001年秋季风对坦帕湾盐度平衡的影响

利用三维高分辨率有限体积的近海海域模型FVCOM来分析2001年秋季期间风作用对坦帕湾区域盐度平衡的影响。为了区分风的影响,分别设计了两个实验：一个由潮汐和河流作为驱动,另一个由潮汐、河流以及风场共同驱动。结论如下：首先,风作用会使盐度产生变化,能够明显地使坦帕湾内的盐度增加,并导致水平和垂直方向上盐度梯度的减少;随后,本文分析了坦帕湾区域内的盐度平衡,主要的盐度平衡来自于全部（水平和垂直方向上）平流的盐度流量分歧以及除去海峡底部的垂直方向上盐度流量分歧;最后,对由风引起的盐度变化进一步进行分析,结果表明风作用不能改变盐度平衡地位的相对重要性,由风引起的盐度平衡改变高度依靠于特殊的地形,除此之外,全部平流盐度流量分歧和垂直散布盐度通量分歧能够抵消,并且两者都远大于水平散步盐度流量分歧。     

基于MTSAT卫星遥感的中国海及西北太平洋海域海表温度日增温研究

Hourly sea surface temperature(SST) observations from the geostationary satellite are increasingly used in studies of the diurnal warming of the surface oceans. The aim of this study is to derive the spatial and temporal distribution of diurnal warming in the China seas and northwestern Pacific Ocean from Multi-functional Transport Satellite(MTSAT) SST. The MTSAT SST is validated against drifting buoy measurements firstly. It shows mean biases is about –0.2°C and standard deviation is about 0.6°C comparable to other satellite SST accuracy. The results show that the tropics, mid-latitudes controlled by subtropical high and marginal seas are frequently affected by large diurnal warming. The Kuroshio and its extension regions are smaller compared with the surrounding regions. A clear seasonal signal, peaking at spring and summer can be seen from the long time series of diurnal warming in the domain in average. It may due to large insolation and low wind speed in spring and summer, while the winter being the opposite. Surface wind speed modulates the amplitude of the diurnal cycle by influencing the surface heat flux and by determining the momentum flux. For the shallow marginal seas, such as the East China Sea, turbidity would be another important factor promoting diurnal warming. It suggests the need for the diurnal variation to be considered in SST measurement, air-sea flux estimation and multiple sensors SST blending.     

温度、盐度和光照对浒苔生长和光合作用的影响

Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels(14–27°C)and high salinity(26–32), with optimum at 23°C and 32. Both low(14°C) and highest temperature(40°C), as well as low salinity(8) had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera(10.6%–16.7% d~(–1)) at a wide range of temperature(5–32°C) and salinity(14–32) implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera.     

大连蜈蚣藻孢子发育及生活史的研究

在实验室条件下,对大连蜈蚣藻(Grateloupia dalianensis H.W.Wang et D.Zhao)的孢子早期发育、盘状体的形成和直立枝生长进行了详细研究,对其生活史进行了详细观察,并进行了温度和光照强度对孢子发育影响的研究。结果表明:(1)孢子发育类型为间接盘状体型;(2)生活史由雌、雄配子体、四分孢子体和果孢子体三相世代组成,配子体与孢子体形态相同,属于同型世代交替,与属模蜈蚣藻(G.filicina)一致;(3)温度对盘状体和直立枝生长均有影响,最适温度均为16℃;(4)光照强度对盘状体和直立枝生长均有影响,最适光照强度分别为7 500 lx和10 000 lx。     

国产抛弃式温度剖面仪(XBT)资料质量分析

国家海洋技术中心根据科研需求研发了抛弃式温度剖面仪(XBT)等一系列抛弃式产品.针对2014年8月份在西太平洋海域投放的XBT和XCTD所获取的温度数据进行对比分析,单剖面结果显示两者相关系数达到了0.95,在温跃层处出现温度差,断面标准差分析结果为200 m以上温跃层处较大而200m以下标准差较小,最大和最小标准差值分别为0.39和0.08.温度断面分析结果显示两者在同样的位置出现等值线的凹凸现象,对大洋水团特殊物理海洋现象描述基本一致.分析温跃层处两者温度存在偏差的原因有3个:不同传感器的不同响应时间引起的误差、深度测量公式的误差以及传感器本身的测量误差影响.国产XBT的数据质量较好,总体上性能能满足对环境复杂海域的快速走航观测,数据质量准确度和可靠性都较好.     

淤泥质潮滩地貌演变中的水动力及生物过程研究进展

淤泥质潮滩对于海岸防护、增加土地资源、保持生物多样性等具有重要作用。从淤泥质潮滩演变的主要驱动因子——潮流、波浪、生物作用及地下过程四个方面回顾和总结了潮滩演变动力地貌过程的相关研究进展,提出应关注潮滩短期演变规律、波浪与浮泥作用机理、生物生长与潮滩演变定量关系,以及地下过程作用机理等。     

中国省际人口迁移的多边效应机制分析

区际人口迁移不仅与迁出地和目的地的要素特征以及距离有关,而且还受到周边迁移流的影响.基于网络自相关理论,利用"六普"省际人口迁移数据和相关统计资料,在重力模型的基础上考虑迁移流之间可能存在的几种空间依赖形式,构建中国省际迁移流的空间OD模型,初步揭示区域经济社会等因素及其空间溢出效应对省际人口迁移的影响,并就区域要素变化对整个省际人口迁移系统产生的"连锁反应"进行了模拟.结果表明:① 中国省际迁移流之间存在显著的网络自相关效应.目的地和迁出地的自相关效应皆为正,导致迁入和迁出流的空间效仿行为;迁出地和目的地周边则出现负的自相关效应,导致迁移流的空间竞争行为;② 区域经济社会等因素通过网络空间关系对周边地区产生的多边溢出效应导致迁移流在空间上集聚.其中,距离衰减效应位居各要素之首,其溢出效应进一步加剧距离的摩擦作用;对目的地而言,区域工资水平和迁移存量超过GDP的影响并产生正的溢出效应,促进周边地区吸引更多的外来人口;对迁出地而言,人口规模和迁移存量产生正的溢出效应,推动周边地区人口外迁;③ 区域要素变化潜在地对整个省际人口迁移系统产生一系列"连锁反应",震荡中心及其周边区域的迁移流波动较大.江苏省GDP增长5%的模拟结果表明,江苏迁往全国其他省份的人口数量都有不同程度地减少,而其他省份入迁人口均有所增加.相对而言,江苏周边省份的迁入或迁出流受到的波动较大,偏远省份波及较小,这是传统的重力模型所无法解释的.     

Electrical analogy for modelling thermal regime and moisture distribution in sandy soils

The soil mass is subjected to temperature variation due to several human activities (viz. tanks storing heated fluids, buried cables and pipelines, air-conditioning ducts, disposal of nuclear and thermal power plant wastes etc.), which result in heat-induced migration of the moisture in it. Though several studies have been conducted in the past to investigate the mechanism of heat migration through the soil mass, a methodology for ‘real-time measurement of the variations in temperature, flux and moving moisture front, in tandem, with respect to space' has rarely been attempted. In this context, extensive laboratory investigations were conducted to measure real-time flux and temperature variations in the sandy soils, and the validation of results has been done by employing an equivalent electrical circuit programme, LTspice. Subsequently, a mathematical model PHITMDS (i.e. Prediction of Heat-Induced Temperature and Moisture Distribution in Soil) has been developed and its utility and efficacy, for predicting the depth-wise temperature and heat-induced moisture migration, due to evaporation, in terms of position of moving moisture front in the sandy soil has been critically discussed and demonstrated.