Wind-driven interannual variability over the northeast Pacific Ocean     

Patrick F. Cummins  Gary S.E. Lagerloef 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):365

Interannual variability of the sea surface height (SSH) over the northeast Pacific Ocean is hindcast with a reduced-gravity, quasi-geostrophic model that includes linear damping. The model is forced with monthly Ekman pumping fields derived from the NCEP reanalysis wind stresses. The numerical solution is compared with SSH observations derived from satellite altimeter data and gridded at a lateral resolution of 1 degree. Provided that the reduced gravity parameter is chosen appropriately, the results demonstrate that the model has significant hindcast skill over interior regions of the basin, away from continental boundaries. A damping time scale of 2 to 3 years is close to optimal, although the hindcast skill is not strongly dependent on this parameter.A simplification of the quasi-geostrophic model is considered in which Rossby waves are eliminated, yielding a Markov model driven by local Ekman pumping. The results approximately reproduce the hindcast skill of the more complete quasi-geostrophic model and indicate that the interannual SSH variability is dominated by the local response to wind forcing. There is a close correspondence the two leading empirical orthogonal modes of the local model and those of the observed SSH anomalies. The latter account for over half of the variance of the interannual signal over the region.  相似文献   

基于荧光原理的叶绿素a传感器校准方法研究     

《海洋技术学报》2024,(1)

利用传感器对水体叶绿素a 浓度进行原位测量是获取实时、连续、长时间序列数据的重要手段。本文在对RBR 传感器和ECO（Environmental Characterization Optics）传感器进行原理分析和线性度、稳定性、重复性等基本性能测试的基础上，利用单一藻种培养液和2020年南海北部海域现场数据校准传感器，并对新的传感器校准系数进行验证。结果表明：两台传感器使用新系数比原出厂系数的叶绿素a 浓度测量准确度有明显提高。RBR 传感器现场数据校准系数的计算结果与叶绿素a 标准值误差最小，平均绝对误差从1.93 μg/L 减小到0.35 μg/L，平均相对误差从55.1%减小到10.9%；ECO 传感器藻液系数明显优于出厂系数和现场数据校准系数的计算结果，平均绝对误差从1.76 μg/L 减小到0.59 μg/L，平均相对误差从50.3%减小到15.1%。传感器测量准确度的提高，可为海洋环境监测、海洋生态灾害预警等工作获取真实可靠数据提供支撑。  相似文献   

Effort distribution and catch patterns adjacent to temperate MPAs   总被引：7，自引：2，他引：7  

Murawski  Steven A.; Wigley  Susan E.; Fogarty  Michael J.; Rago  Paul J.; Mountain  David G. 《ICES Journal of Marine Science》2005,62(6):1150-1167

  相似文献   

梭鱼仔鱼耳石日轮形成及自然种群日龄的鉴定   总被引：2，自引：0，他引：2       下载免费PDF全文

李城华  沙学绅  尤锋  杨纯武  黄瑞东 《海洋与湖沼》1993,(4)

梭鱼实验种群样本,系于1987年5月,从山东大沽河口搜集的亲鱼经人工授精后孵出的仔鱼在实验室培育取得;自然种群样本,于同年同地区采集。对于实验种群耳石生长轮形成的周期性进行了研究。结果表明,实验种群培育天数(D)与耳石生长轮数(N)之间的关系以回归式N=D-1.89表达之;根据实验种群耳石轮纹形成的周期性规律,鉴定了自然种群的日龄,表明二者具相似的周期性规律;协方差分析表明,梭鱼早期阶段的生长,自然种群比实验种群快。  相似文献   

计算数据域特征值的两种算法     

洪忠渝 《中国海洋大学学报(自然科学版)》1994,(Z2)

设计两种计算数据域特征值的算法。此特征值通常是用线性反馈移位寄存器（ＬＦ－ＳＲ）组成的特征分析器得到的．在数据已按字节存放和速度要求不高的场合下，本算法将是十分方便和有用的．  相似文献   

Monitoring the Kuroshio Extension with Dynamically Constrained Synthesis of the Acoustic Tomography, Satellite Altimeter and in situ Data     

Konstantin V. Lebedev  Max Yaremchuk  Humio Mitsudera  Iwao Nakano  Gang Yuan 《Journal of Oceanography》2003,59(6):751-763

A finite-difference quasigeostrophic (QG) model of an open ocean region has been employed to produce a dynamically constrained synthesis of acoustic tomography and satellite altimetry data with in situ observations. The assimilation algorithm is based upon the 4D variational data interpolation scheme controlled by the model's initial and boundary conditions. The data sets analyzed include direct and differential travel times measured at the array of five acoustic transceivers deployed by JAMSTEC in the region of the Kuroshio Extension in 1997, Topex/Poseidon altimetry, CTD soundings, and ADCP velocity profiles. The region monitored is located within the area 27.5°–36.5°N, 143°–155°. The results of assimilation show that mesoscale variability can be effectively reconstructed by five transceivers measuring direct and reciprocal travel times supported by relatively sparse in situ measurements. The misfits between model and data lie within the observational error bars for all the data types used in assimilation. We have compared the results of assimilation with the statistical inversion of travel time data and analyzed energy balances of the optimized model solution. Energy exchange between the depth-averaged and shear components of the observed currents reveals a weak decay of the barotropic mode at the rate of 0.2 ± 0.7⋅10⁻⁵ cm²/s³ due to topographic interaction. Mean currents in the region are unstable with an estimate of the available potential energy flux from the mean current to the eddies of 4.7 ± 2.3⋅10⁻⁵ cm²/s³. Kinetic energy transition has the same sign and is estimated as 2.8 ± 2.5⋅10⁻⁵ cm²/s³. Potential enstrophy is transferred to the mesoscale at a rate of 5.5 ± 2.7⋅10⁻¹⁸ s⁻³. These figures provide observational evidence of the properties of free geostrophic turbulence which were predicted by theory and observed in numerical experiments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

海洋调查数据的可视化建模及实现方法     

孙菁  杨冠杰 《中国海洋大学学报(自然科学版)》2001,31(4):579-585

科学计算可视化作为新一代的分析工具 ,正在进入物理海洋学领域。文中介绍对海洋调查数据进行可视化的关键问题——数据建模 ,并从分析海洋调查数据的特点出发提出针对海洋研究中可视化建模的原则和有效途径 ,给出相关的实现方法。其中 ,重点讨论局部体样条建模中必须面对的区域分割优化问题 ,引入遗传算法并给出较好的解决方案。  相似文献   

基于分布式检测与决策融合的海底油气管线检漏   总被引：3，自引：0，他引：3  

白莉  岳前进崔莉 《海洋工程》2006,24(1):55-59

利用多传感器的信息融合思想，提出分布式检测与决策融合方法进行长距离海底管线泄漏监测。试验水管和天然气／凝析油管线现场数据分析表明此算法不仅降低了误报警概率，且对流体在输送过程中动态变化具有稳健性。  相似文献   

潮汐调和分析的一种算法   总被引：1，自引：1，他引：1  

宋志尧  严以新  茅丽华 《海洋工程》1997,(3)

本文在常规潮汐调和分析方法的基础上，提出了一种由高低潮资料进行潮汐分析的算法。具体计算表明，该算法与现今通用的常规算法（即等间隔最小二乘法）相比，既可大大减少所需原始样本量，在相同记录长度内，是常规算法的三分之一还少，同时减少样本处理的前期工作量；又能保证潮位拟合的精度和预报的可信度，两者精度相当，结果一致。该算法原理简单、实用有效，对于局部样本缺损较易处理，具有实际应用价值。  相似文献   

Sources and hydrothermal alteration of organic matter in Quaternary sediments: A synthesis of studies from the Central Gulf of California     

Bernd R. T. Simoneit 《Marine and Petroleum Geology》1986,3(4)

Deep sea drilling in the Central Gulf of California, a young and active spreading centre, shows that the high heat flow typical of these regions causes extensive alteration of sediment organic matter, especially near sills and above magma chambers where hydrothermal activity is concentrated. Even on the nearby passive margin, where there are no sills, heat flow is moderately high and hydrocarbon generation has begun in immature sequences. Migrating light hydrocarbons are detected especially where hydrothermal activity is concentrated. Thermogenic methane is more widespread, though not in the passive margin bordering the spreading centre. Despite the incidence of hydrocarbon generation and migration, the amounts of hydrocarbons involved are relatively small and apparently do not lead to commercially significant accumulations of petroleum.The organic matter in these sediments is mostly marine because the Gulf of California generally has low runoff from land and highly productive surface waters. Turbidites rich in terrigenous organic material are locally abundant in the mainly pelagic section in the Guaymas Basin. The highest concentrations of organic matter are found in laminated diatomites deposited on the Guaymas passive margin within the oxygen minimum zone.  相似文献