粉质土海底边界层动态演化过程波浪水槽实验     

文明征  贾永刚  王振豪  张少同  单红仙 《海洋学报(英文版)》2020,42(5):96-104

The objectives of this study are carried out a series of controlled large wave flume experiments using fine-grained sediment from the Huanghe River Delta, exploring the complete sequence of sediment behavior in the bottom boundary layer(BBL) during wave-induced liquefaction. The results show that:(1) The BBL in silty seabed is exposed to a progressive wave, goes through a number of different stages including compaction before liquefaction, sediment liquefaction, and compaction after liquefaction, which determines the range and thickness of BBL.(2) With the introduction of waves, first, the sediment surface has settled by an amount S(S=1–2 cm) in the course of wave loadings with an insufficient accumulation of pore water pressure. And a thin high concentration layer formed the near-bed bottom.(3) Once the liquefaction sets in, the liquefied sediment with an ‘orbital motion' and the sub-liquefied sediment form a two-layer-sediment region. The range of BBL extends downwards and stopped at a certain depth, subsequently, develops upwards with the compaction process. Meanwhile, resuspended sediments diffuse to the upper water column.(4) During the dynamics process of the BBL beneath progressive waves, the re-suspended sediment increment ranked as sediment liquefaction erosion before liquefaction compaction after liquefaction.  相似文献   

The impact of northern Indian Ocean rivers on the Bay of Bengal using NEMO global ocean model     

Srivastava Atul  Gera Anith  Momin Imran M.  Mitra Ashis Kumar  Gupta Ankur 《海洋学报(英文版)》2020,39(3):45-55

The effect of river runoff over the northern Indian Ocean(NIO) especially over the Bay of Bengal(Bo B) has been studied using global Nucleus for European Modelling of the Ocean(NEMO). Two sensitivity experiments, with and without river runoff are conducted and the influence of river runoff on the Indian Ocean hydrography,stratification and circulation features are studied. It is found that due to river runoff surface salinity over the northern Bo B decreases by more than 5 and the East India Coastal Current strengthens by 2 cm/s during post monsoon season. The fresh river water reaches up to 15°N in the Bo B and is the main cause for low salinity there.Sea surface temperature in the northwestern Bo B increases by more than 0.2℃ due to the river runoff in summer monsoon while surface cooling upto 0.2℃ is seen in north-west part of Bo B in winter season. The seasonal mixed layer depth in the region is found to be dependent on river runoff. The effect of vertical shear and Brunt Vaisala frequency on stratification is also examined. The ocean water becomes highly stratified up to 3 035 m due to the river runoff. It is found that the energy required for mixing is high in the northern and coastal Bo B.  相似文献   

琼胶/SiO₂复合纤维的制备及性能研究     

吴大伟  颜廷波  李腾飞  王应霞  肖玉斌  薛志欣  夏延致 《海洋科学》2020,44(10):39-45

利用湿法纺丝技术制备了琼胶/SiO₂复合纤维，对琼胶分子在溶液中的分散性、纺丝液流变性、纤维的形貌、化学结构分别用DLS、旋转黏度计、SEM、FTIR和XRD进行了表征，并对纤维的力学性能、热性能和吸湿性能进行了测定。研究结果表明：琼胶分子在溶液中呈纳米尺度分布，纺丝液具有良好的流动性；琼胶/纳米SiO₂复合纤维具有良好的形态。随着纳米SiO₂的添加量逐渐提高，复合纤维的力学拉伸强度先增强后降低，复合纤维的吸水性降低，复合纤维的热稳定性逐渐增强。结合复合纤维综合性能，纳米SiO₂的最佳添加质量分数为0.5%。  相似文献   

青岛地区海雾分布及大气边界层条件分析     

任兆鹏  李昊倩  鞠霞  王国清 《海洋科学》2020,44(5):96-106

青岛地区海雾多发,观测表明海雾对沿海地区影响范围不尽相同,特别是海雾影响内陆的机理尚缺乏研究。本文利用观测资料及数值模式统计了青岛地区4月-7月海雾分布特征,并对不同影响范围海雾典型个例进行对比分析,结果表明:海雾发生日数自沿海向内陆递减。胶州湾沿岸雾日数比黄海沿岸明显减少,胶州湾东北部的雾日数要少于胶州湾西北部。海雾多发生于高空形势稳定,低层偏南流场的天气条件下。大气边界层内逆温层的的范围大致影响着海雾的分布。只影响沿海的海雾,地面为偏南风,风速在3~8 m/s之间,内陆风力减弱不明显。500 m以下大气边界层内风速切变大。湍流作用使海雾向内陆推进过程中倾斜抬升为低云,地面雾区减弱。能够影响内陆地区的海雾,多出现在地面风力较弱的情况之下,大部分在1~3 m/s之间。500 m以下大气边界层内风速切变小,大气边界层内湍流强度不强,使沿海到内陆的逆温层能够始终维持,沿海海雾在弱南风影响下延伸影响内陆地区。  相似文献   

羧乙基壳聚糖蒙脱石吸附养殖水体中Cu²⁺的应用     

李俭平  周忻宇  代婧炜  沈庆洲 《海洋科学》2020,44(2):120-130

为了寻求性能良好、环保吸附剂,用于去除养殖水体中重金属Cu~(2+),作者利用蒙脱石负载羧乙基壳聚糖制备成复合吸附剂,并利用IR、SEM、XRD等手段分析其表面性能,将其用于处理Cu~(2+)溶液,考察了环境因子对其吸附性能的影响,并从吸附动力学和吸附热力学角度分析吸附剂对Cu~(2+)的吸附机理,最后考察其再生利用效果。结果表明:羧乙基壳聚糖成功进入到蒙脱石层间;在羧乙基壳聚糖与蒙脱石质量比为1︰25、40℃恒温水浴搅拌60min、pH=6.0、最佳投加量为4.0g/L、处理浓度不超过30 mg/L Cu~(2+)溶液时,复合吸附剂对Cu~(2+)去除率可以达到96.23%,将其用于淡水养殖鱼塘水体中, Cu~(2+)去除后可达到《渔业水质标准》规定;吸附剂对Cu~(2+)吸附热力学实验结果表明,符合Langmuir模型,反应过程为自发、吸热反应;吸附动力学结果表明该吸附符合准二级动力学方程,反应属于化学吸附;再生实验中NaOH的再生效果优于HCl。  相似文献   

基于核函数NPSSB模型的HY-2A卫星雷达高度计海况偏差研究     

张洁  田杰  王兆徽 《海洋预报》2020,37(1):1-10

利用机器学习的方法,对14个周期HY-2A卫星高度计数据:风速、有效波高和海面高度差值进行训练,探究海况偏差和风速、有效波高之间的关系,创建海况偏差核函数非参数模型(NPSSB),并与参数模型中具有代表性的BM3、BM4模型进行对比。研究表明:(1)核函数NPSSB模型能够很好的反映SSB与U、SWH之间的关系,SSB与U呈二次函数关系,SSB与SWH呈反比例函数关系;(2)核函数NPSSB模型对SSB的模拟能力与训练数据集相关,数据量越多,模拟能力越好;(3)核函数NPSSB模型与BM3、BM4模型都存在0^-0.03 m的差值,随着风速和有效波高的增加,差值的绝对值越大。  相似文献   

HY-2B卫星散射计海面风场产品质量分析 *     

陈克海  解学通  张金兰  邹巨洪  张毅 《热带海洋学报》2020,39(6):30-40

星载微波散射计是获取全球海面风场信息的主要手段, HY-2B卫星散射计的成功发射为全球海面风场数据获取的持续性提供了重要保障。本文利用欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts, ECMWF)再分析风场数据、热带大气海洋观测计划(Tropical Atmosphere Ocean Array, TAO)和美国国家数据浮标中心(National Data Buoy Center, NDBC)浮标获取的海面风矢量实测数据, 对HY-2B散射计海面风场数据产品的质量进行统计分析。分析表明, HY-2B风场与ECMWF再分析风场对比, 在4~24m·s^-1风速区间内, 风速和风向均方根误差(root mean square error, RMSE)分别为1.58m·s^-1和15.34°; 与位于开阔海域的TAO浮标数据对比, 风速、风向RMSE分别为1.03m·s^-1和14.98°, 可见HY-2B风场能较好地满足业务化应用的精度要求(风速优于2m·s^-1, 风向优于20°)。与主要位于近海海域的NDBC浮标对比, HY-2B风场的风速、风向RMSE分别为1.60m·s^-1和19.14°, 说明HY-2B散射计同时具备了对近海海域风场的良好观测能力。本文还发现HY-2B风场质量会随风速、地面交轨位置等变化, 为用户更好地使用HY-2B风场产品提供参考。  相似文献   

北太平洋副热带模态水盐度的年代际变化     

胡睿坤  边志刚  刘子洲  刘聪  翟方国  顾艳镇 《中国海洋大学学报(自然科学版)》2020,(2):9-21

副热带模态水(Subtropical Mode Water;STMW)在气候变化中起着重要作用。本文利用全球高分辨率数值模拟结果,研究了北太平洋STMW核心层盐度(Core Layer Salinity;CLS)的年代际变化及其物理机制。结果表明,CLS存在显著的年代际变化,其空间分布则与背景流场分布特征有关。侵蚀区CLS滞后生成区CLS约1~2年,这主要是海流平流输运引起的。生成区内,STMW的季节循环一般可分为生成期(12-4月)、隔离期(5-6月)和侵蚀期(7-11月),生成期混合层盐度(Mixed Layer Salinity;MLS)决定着隔离期和侵蚀期的CLS,而MLS年代际变化则主要由同太平洋年代际涛动存在负相关性的海表面淡水通量的变化引起。  相似文献   

Cu2+对序批式反应器中活性污泥胞外聚合物产量及其组分的影响     

李姗姗  朱四富  马丙瑞  于娜玲  赵长坤  信帅帅  潘云浩  吴淑妍  武原原  高孟春 《中国海洋大学学报(自然科学版)》2020,(2):107-115

研究了长期暴露条件下Cu2+对序批式反应器(SBR)性能及其活性污泥胞外聚合物(EPS)特性的影响。结果表明,进水中加入10 mg·L-1的Cu2+后,在SBR运行的第16~55天,COD和NH+4-N的去除率保持稳定;在第56~75天,COD和NH+4-N的平均去除率与进水Cu2+浓度为0 mg·L-1时相比分别下降了3.88%和6.41%。浓度为10 mg·L-1的Cu2+长期作用下,活性污泥中EPS、松散附着EPS(LB-EPS)和紧密附着EPS(TB-EPS)产量及LB-EPS和TB-EPS中蛋白质(PN)含量增加。傅里叶变换红外光谱分析表明10 mg·L-1 Cu2+的长期暴露导致TB-EPS中PN的C=O键、N-H键和C-O键相对含量降低。X射线光电子能谱(XPS)测试结果显示在10 mg·L-1 Cu2+长期暴露条件下,LB-EPS和TB-EPS中元素Cu和O百分含量增加。  相似文献   

Evaporation modelling by heuristic regression approaches using only temperature data   总被引：1，自引：1，他引：0  

Ozgur Kisi  Salim Heddam 《水文科学杂志》2019,64(6):653-672

Accurate estimation of pan evaporation (E_pan) is very important in water resources management, irrigation scheduling and water budget of lakes. This study investigates the accuracy of two heuristic regression approaches, multivariate adaptive regression splines (MARS) and M5 model tree (M5Tree) in estimating pan evaporation using only temperature data as input. Monthly minimum temperature, maximum temperature and E_pan data from three Turkish stations were used, with month number (periodicity information) added as input to see its effect on estimation accuracy. The models were compared with the calibrated Hargreaves-Samani (CHS), Stephens-Stewart (SS) and multiple linear regression methods. Three different train-test splitting strategies (50%–50%, 60%–40% and 75%–25%) were employed for better evaluation of the applied methods. The results show that the MARS method generally estimated monthly E_pan with higher accuracy compared to the M5Tree, CHS and SS methods. When extraterrestrial radiation, calculated from Julian date and latitude information, was used as input to the SS instead of solar radiation, satisfactory estimates were obtained. A positive effect on model accuracy was observed when involving periodicity information in inputs and increasing training data length.  相似文献