珠江河口底边界层湍流积分尺度研究   总被引：2，自引：1，他引：1  

刘欢  吴超羽  许炜铭 《海洋工程》2008,26(4)

介绍湍流积分尺度的几种常用计算方法.基于三组珠江口崖门的湍流观测资料,分别计算了一个潮周期内珠江口底边界层湍流积分尺度的变化,并对比不同计算方法的稳定性.计算结果表明,基于Taylor假定的自相关函数积分法的计算结果稳定可靠.湍流积分尺度在一个潮周期内的变化很大,积分尺度的变化与平均流的流速变化有着很好的对应关系,三个测次纵向、横向和垂向积分尺度的平均值分别约为4.9～10.4 cm、3.3～6.2 cm和4.3～5.2 cm.  相似文献   

Polychlorinated dibenzo-p-dioxins （PCDDs） and dibenzofurans （PCDFs） in surface sediment and bivalve from the Changjiang Estuary, China   总被引：1，自引：0，他引：1  

闻胜  惠阳  杨方星  刘征涛  徐盈 《中国海洋湖沼学报》2008,26(1):35-44

Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.  相似文献   

Concentrations and distribution of organochlorine pesticides in shellfish from Changjiang estuary   总被引：1，自引：0，他引：1  

马继臻  沈新强  袁骐  蒋玫 《中国海洋湖沼学报》2008,26(4):388-393

To analyze and evaluate the status of organochlorine pollutants in the Changjiang (Yangtze River) estuary and adjacent waters, the concentrations of hexachlorocyclohexane (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in shellfish collected in study area from 2006 to 2007 were determined with gas chromatography (GC). The concentration range of HCHs was (ND-12.13)×10-3 mg/kg wet weight and averaged at 0.54×10-3 mg/kg while the concentration of DDTs was in the range of (4.06-281.73) × 10-3 mg/kg with a mean of 57.52×10-3 mg/kg in the survey areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorine pollutants in the areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorines pollutants. The HCHs in all the shellfish conformed to the first level of criterion (0.02 mg/kg) of the Marion Biology Quality (GB 18421-2001), and that of DDTs in most samples were beyond the first level (0.01 mg/kg) but conformed to the second level (0.10 mg/kg). On average, α-HCH and δ-HCH occupied the most part of HCHs, while O,P'-DDT and P,P'-DDT occupied the most part of DDTs. The concentrations of organocholorine pesticides in shellfish samples varied in site and in species. The highest level occurred at the Shengsi (SS), followed by Yangkougang (YKG), Lvsi (LS), Dongyuan (DY) and Beibayao (BBY), low concentrations were observed at Changsha (CS), Beidaodi (BDD), and Gouqi (GQ). The concentration of HCHs and DDTs in most sites decreased clearly from 2006 to 2007 except for YKG, DY, BDD, LYS, and SS. All of above results suggested that the study area was slightly affected by organochlorine pesticide, special by DDTs.  相似文献   

海水介质中漂白珍珠长麻率研究     

李雪英  王海增  郭鲁钢  张际标 《广东海洋大学学报》2007,27(1):52-54

以海水为溶剂进行珍珠漂白,探讨双氧水浓度、漂白液pH值和漂白时间与珍珠长麻情况之间的关系。结果表明:从抑制珍珠长麻方面考虑,最佳双氧水的浓度为5%,漂白液pH值为8.60,漂白时间为3d。  相似文献   

长江河口岸滩侵蚀演变模式   总被引：2，自引：0，他引：2  

胡刚  沈焕庭  庄克琳  周良勇  刘健 《海洋地质与第四纪地质》2007,27(1):13-21

长江河口地区由于流域带来的泥沙沉降堆积,形成了巨大的长江三角洲平原和水下三角洲。近年来,由于水土保持和流域建水库使得入海泥沙迅速减少,造成长江河口区岸滩侵蚀态势逐渐加重。根据多年海图资料得到的岸滩剖面变化,长江河口区岸滩侵蚀的演变模式按岸滩侵蚀剖面形态特征分为平直型、宽陡型和尖陡型;按剖面的变化特征可分为平行后退型、下凹变上凸型和宽陡变尖陡型。  相似文献   

广利河口航道整治研究     

饶永红  陈兆林  孙国峰  杨洪旗 《海洋工程》2007,25(1):120-126

广利河口拦门沙航道水深较浅,用双导堤结合航道疏浚进行整治。通过潮流定床模型试验对航道走向、导堤间距、高程、水流流态和堤头布置等进行了方案优化,同时采用局部动床定性试验进行了验证。推荐方案沿程流速、流态分布合理,基本能维持航道水深并满足设计船型的航行条件,可供类似河口治理参考。  相似文献   

Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary   总被引：1，自引：0，他引：1  

LIU Qizhen  LI Jiuf  DAI Zhijun  LI Daoji 《海洋学报(英文版)》2007,26(1):140-149

1 IntroductionThe flocculation of fine-grained particles is onof the main reasons for the estuarine depositionWith the combination of salt water and freshwaterfine-grained particles in estuaries will experiencdrastic changes: flocculation, settlement, res…  相似文献   

鱼溶浆粉在珍珠龙胆石斑鱼幼鱼的高植物蛋白饲料中的应用     

孙永智  宋志东  李培玉  李宝山  王成强  王晓艳  王际英  郝甜甜  马季  黄炳山 《中国海洋大学学报(自然科学版)》2021,51(1):31-43

为研究高植物蛋白饲料中添加鱼溶浆粉对珍珠龙胆石斑鱼(Epinephelus fuscoguttatus♀ ×E.lanceolatu♂)幼鱼的生长性能、体组成、血清生化指标、非特异性免疫及肠道组织结构的影响.以(23.72±0.09)g的珍珠龙胆石斑鱼幼鱼为研究对象,添加60％ 白鱼粉为对照组(DF),用30％ 大豆浓...  相似文献   

0601号台风"珍珠"路径及舟山沿海风雨特征分析     

张伟红  何宽科 《海洋预报》2007,24(4):65-70

受0601号台风“珍珠”和弱冷空气共同影响,2006年5月1 8日舟山普降暴雨,18日下午至19日早晨,舟山沿海海面风力达到11级,11级大风持续时间长达20个小时。本文利用常规资料对台风“珍珠”路径和舟山风雨特征进行了分析,分析表明：台风“珍珠”移动路径属抛物线状登陆转向路径,它主要是由副热带高压和西风槽影响形成的。对于早期登陆北卜的台风,预报上要着重考虑中纬度西风槽、冷空气与台风环流相互结合时降水、风力的不对称分布。台风与西风槽相互作用有利于台风暴雨的加强。台风环流与弱冷空气的相互作用促使台风倒槽发展,使结合区域强风出现时间提前,持续时间加长。  相似文献   

小清河口氮磷营养物基准制定     

《中国海洋大学学报(自然科学版)》2021,51(7)

本文采用频数分布法和压力-响应模型法分别推导小清河口营养物基准,其中频数分布法根据河口所有监测站位营养物浓度的下第5个百分点作为基准值;压力-响应模型法选取小清河口三种常见赤潮藻中肋骨条藻(Skeletonema costatum)、赤潮异弯藻(Heterosigma akashiwo)和微型原甲藻(Prorocentrum minimum)为实验对象,建立河口营养物水平与浮游藻生长之间的压力响应关系模型并推导生态基准值。频数分布法得出的小清河口总氮(TN)、总磷(TP)、溶解无机氮(DIN)和活性磷酸盐(SRP)基准值分别为5.18、0.14、3.33和0.015 mg/L。由于小清河口氮污染严重,现场调查得到的TN和DIN均值均远超我国地表水环境质量标准IV类值(1.5 mg/L)和海水水质标准IV类值(0.5 mg/L),因此频数分布法推导的TN和DIN基准值不推荐为小清河口营养物基准值。压力-响应模型法推导的四种营养物基准值分别为0.23、0.059、0.17和0.020 mg/L,该值可作为小清河口营养物基准推荐值,以期为小清河口营养物标准制定和生态风险评估提供科学依据。  相似文献