黄海晚冬一次持续性海雾天气的动力热力特征

利用常规资料、NCEP 1°×1°再分析资料、高分辨率可见光卫星云图资料,描述了2011年2月22-24日持续性海雾的发生范围、演变过程,分析了海雾发生前、发生时大气背景和物理量场;并利用环黄海北部的探空站、气象自动站资料对海雾发生时低层大气的温度、风、逆温特征进行了分析.结果表明:环黄海北部4个气象站中,各站出现海雾的特征不尽相同,既有以平流雾为主的、也有辐射雾为主的、还有平流雾和辐射雾共存的.对流层低层暖平流有助于保持逆温层、维持大气层结稳定;对流层低层偏南气流形成的水汽输送带和中层偏西气流水汽输送带的共同作用为大雾的形成和维持提供了水汽条件;夜晚低层辐合、高层辐散的动力分布有助于逆温层内弱的上升气流维持,对水汽凝结有利;白天低层辐散、高层辐合的动力分布有助于气流下沉,对稳定度和逆温的维持有利;负(冷)温度平流南下是大雾消散的动力热力因子.     

环渤海沿岸海表温度资料的均一性检验与订正

本文对环渤海沿岸具有代表性且资料完整的6个海洋观测站的月均海表温度(SST)序列作均一性检验和订正。我国海洋观测站密集度低,难以选择参考序列,本文首先采用不依赖参考序列的惩罚最大F检验(PMFT)方法对SST序列检验,利用详尽的元数据对检验结果进行确认,再对不连续点订正,该方法适用于元数据详尽的海洋观测站。对于元数据不详尽的观测站,使用惩罚最大T检验(PMT)方法,选取与海洋台站距离近且相关显著的气象观测站的均一化地面气温序列来制作参考序列,对SST序列进行检验和订正。结果表明,环渤海地区SST序列都存在一定非均一性,观测站较大距离迁移和观测系统变更(从人工观测到自动化观测)是造成非均一性的重要原因。订正后的环渤海地区年平均SST增温趋势更加明显。本文使用不同方法来检验SST序列的均一性,该思路对沿海其他海区观测站SST均一性检验和订正有一定参考价值和应用前景,可为沿海气候变化研究提供科学准确的第一手资料。     

中国近海ASCAT和ERA-Interim风场资料的评估

利用中国近海23个浮标对2015年一整年的ASCAT轨道风场和ERA-Interim再分析风场进行质量评估,并对比了ERA-Interim和CFSV2两种再分析风场资料在中国近海的适用性。结果表明:ASCAT在中国近海与浮标风速的一致性优于ERA-Interim,而二者与浮标风向的一致性则相差不大。同时,对比CFSV2与ERA-Interim的误差统计结果发现,CFSV2的风速误差较ERAInterim略小,风向误差相差不大。     

基于CCMP资料和现场观测资料的西北太平洋海面风场特征分析

利用由美国宇航局物理海洋学数据分布存档中心发布的2007—2011年CCMP风场资料,针对西北太平洋海面风场的季、月、日变化特征进行了分析。结果表明:西北太平洋海面风场具有明显的季、月变化特征,夏季盛行西南风,风向多变,风速最低;冬季盛行东北风,风速偏高。大风频发区域位于南海海域、台湾海峡和日本岛以东,且冬季发生频率明显高于其他3个季节。此外,还利用获取到的2014年8月海面自动观测站和9月海上探空资料对相应月份的风场特征进行细化分析,表明8月洋区盛行西南风,而9月西南风逐渐消退,风速减小,变化特征与相应月份CCMP的海面风分析相符。     

珠江口外走航ADCP资料的系统误差订正与质量控制

在对珠江口外2006年冬季航次走航ADCP观测资料处理中发现用Joyce的方法不能有效地订正系统误差,其原因在于订正角与航速、船艏向相关。给出了一个订正角为船艏向余弦的拟合函数,得出良好的订正结果。分析了VmDas软件处理流速结果的精度,给出了系统误差识别的方法。发现观测资料中一些不能为VmDas软件识别的错误数据,分析了海况对观测资料的影响,提出了观测资料质量控制与误差订正的一套程序。     

船舶动力定位系统的预测模糊控制

在船舶动力定位中采用预测模糊控制策略,即通过自校正滤波与Ｋａｌｍ ａｎ 滤波得到系统低频运动位置偏差与相应速度的预测值作为模糊控制器的输入,以实现对其在水平面内的运动控制。因为基于系统模型的滤波器输出最终是经模糊化后输入至模糊控制器的,于是可大大降低对系统建模的精度要求,控制器本身具有强的鲁棒性。仿真结果说明了该策略的可行性及良好的控制性能。     

基于1987-2010年实测资料对PN断面东海黑潮季节变化的分析

As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce...     

基于ConvGRU和自注意力的海表温度偏差订正研究

海表温度（Sea Surface Temperature, SST） 是一个重要的海洋物理量, 其准确预报对于水产养殖和预测海洋环境信息等海洋相关领域的研究至关重要。数值预报是目前预报海表温度的一种常用方法, 但数值预报模型所产生的预报结果往往与实际观测数据有偏差, 因此有必要对数值预报产品的偏差进行订正。本文提出了一种结合ConvGRU 神经网络与自注意力（Self-Attention, SA） 的新型时空混合海表温度订正模型（ConvGRU-SA）, 对南海海表温度预报数据进行偏差订正, 该模型适用于利用卫星遥感数据对海表温度数值预报产品进行订正。经与ConvLSTM、ConvGRU 等网络模型对比, 证明了ConvGRU-SA 模型的优越性, 设置不同的超参 数进行实验, 提高模型订正准确率。订正后该区域的海表温度预报均方根误差从0.52 ℃降低至0.32 ℃, 准确率提高了38.4%, 优于现有模型。     

渤海海面风场的一种动力诊断方法

给出一种动力诊断获取渤海海面风场的简便方法.首先建立一个简单的水平二维地面风场诊断模式,根据由微机支持的数字化仪输入的地面格点气压场,诊断出地面风场;然后利用渤海沿岸和岛屿海洋观测站(含石油平台站)实测风资料,运用简单的资料同化方法(张驰逼近方法)对诊断风场进行调整,从而得到渤海海面风场.结果表明,此方法简便有效.     

基于实测数据的海上风电结构动力响应分析

地震是危害海上风电结构作业安全的重要环境因素,目前,国内尚未公开发表真实地震响应下,海上风电结构的实测动力响应数据。分析了某地震活动区海上风电结构的实测地震响应,采用随机子空间识别方法进行风机的模态识别,阐述了风机机舱偏航将引起前后、左右两个正交方向振动的耦合,并从理论上证明了利用耦合、解耦数据识别模态参数的差异。结果表明：1）耦合与解耦信号识别的频率、阻尼比完全相同,而耦合信号识别的模态振型与偏航角有关;2）地震作用会对结构产生巨大冲击;3）非地震作用下,风机塔筒前后、左右第一阶弯曲模态为主要模态,地震作用可以激发风机的高阶模态,使得塔筒中上部而不是顶部的振动响应最大。此分析对地震活动区海上风电结构的抗震设计具有一定的参考价值。     

Depth dependence of noise resulting from ship traffic and wind

Under conditions of distantly generated noise, the noise level is found to decrease with depth in the mid-northeastern Pacific. These data show a decrease in noise level greater than 25 dB between critical depth and the ocean bottom. A result of this decrease is that locally wind-generated noise can be detected on near-bottom receivers for wind speeds less than 10 kn. It is shown that the noise level generated form local sources such as wind and nearby shipping is almost independent of receiver depth. The differences in spectra shape between the distant shipping noise and wind-generated noise and the low noise levels detected near the ocean bottom allow the measurement in the frequency band at 200-500 Hz of local wind noise level for wind speeds less than 10 kn     

Statistical study on the local equilibrium between wind and wind waves by using data from ocean data buoy stations

The local equilibrium between the wind and wind waves, which is defined by a range of the coefficient of the 3/2-power law between the non-dimensional significant wave height and period, is statistically investigated by using wind and wave data obtained at four ocean data buoy stations in the seas near Japan. The friction velocity is calculated from the wind speed measured at one height together with the significant wave period by using formulas of the wave dependent drag coefficient proposed by Tobaet al. (1990). The data for small waves or for weak winds indicate that the waves do not satisfy the criterion for the local equilibrium, because they may be affected by changing winds or remotely generated swells. In the seas near Japan, the data which satisfy the local equilibrium are about 6% through a year. Otherwise swells are dominant in most situations. Changing winds also cause deviations from the local equilibrium. The degree of satisfaction of the local equilibrium can be classified by ranges of the significant wave height. As the significant wave height exceeds 4 m, the local equilibrium is more frequently satisfied.     

Hardware correction of dynamic errors in measuring salinity by usingCTD-systems

We study the procedures aimed at decreasing the dynamic errors of the evaluation of salinity with the help ofCTD-probes by reducing the difference between the amplitude-phase characteristics of temperature and conductivity sensors. This is attained by introducing a delay between the times of scanning the sensors. To make the amplitude characteristics as close as possible, we propose to use temperature sensors distributed in the direction of probing. We present the procedures used to determine the optimal parameters of temperature sensors and the length of time delay. The advantages of the proposed method are demonstrated by analyzing a numerical example. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

据赤道经向风剖面及岛屿站风资料诊断厄尔尼诺事件

据赤道经向风剖面及热带西太平洋岛屿站测风资料来诊断厄尔尼诺（ＥｌＮｉｎｏ）事件,试图从观测事实方面来跟踪与预测ＥｌＮｉｎｏ的发生。分析结果得出：气候监测公报中８５０ｈＰａ风指数对监测、诊断已发生的ＥｌＮｉｎｏ事件较好,但不能用来预测ＥｌＮｉｎｏ事件的发生,而热带西太平洋岛屿站月平均纬向风对ＥｌＮｉｎｏ事件的发生有一定的指示意义。从越赤道气流的演变特征进一步证明,ＥｌＮｉｎｏ事件对应于弱季风,而拉尼娜（ＬａＮｉｎａ）事件对应于强季风。     

海域使用时空数据动态管理技术研究

运用面向对象方法的方法,对Geodatabase数据模型进行扩展,研究了海域使用时空数据的结构化存储技术,实现了历史数据的回溯和海域使用数据的变化跟踪等功能.结合厦门市海域使用动态管理的需求进行了应用研究,结果表明, Geodatabase 扩展数据模型研究成果很好地解决了宗海的历史回溯、变化跟踪、时态关系计算等问题.海域动态管理技术研究对海域管理具有重要意义.     

Numerical simulation of ship stability for dynamic environment

The prediction of ship stability during the early stages of design is very important from the point of vessel’s safety. Out of the six motions of a ship, the critical motion leading to capsize of a vessel is the rolling motion. In the present study, particular attention is paid to the performance of a ship in beam sea. The linear ship response in waves is evaluated using strip theory. Critical condition in the rolling motion of a ship is when it is subjected to synchronous beam waves. In this paper, a nonlinear approach has been tried to predict the roll response of a vessel. Various representations of damping and restoring terms found in the literature are investigated. A parametric investigation is undertaken to identify the effect of a number of key parameters like wave amplitude, wave frequency, metacentric height, etc.     

ADCP测量数据深度值的正确解析

介绍了声学多普勒流速剖面仪(ADCP)测流和测深的基本原理,着重论述了汇整ADCP测量的层深、水深数据的误差来源、判读和校正方法,并给出了实用的计算公式。本文研究的方法对于船载、向下观测的走航、定点ADCP测量深度数据的处理,精确定位海流测量结果、保证海流测量结果反映真实海洋环境状况,具有实际的应用价值,同时能够为锚系ADCP测量层深与水深数据的处理提供可参考的技术依据。     

Reconciling thermodynamic and dynamic methods of computation of water-mass transformation rates

The computation of the water-mass transformation rate in a particular density range from thermodynamic and dynamic methods are compared and reconciled by diagnosis of the Atlantic sector of a global integration of an ocean model driven by analyzed air–sea fluxes. In the absence of diffusive processes, the rate of subduction of fluid between two density surfaces across a fixed control surface, and integrated across the ocean from one solid boundary to another, must be equal to the rate of formation of fluid at the sea surface induced by surface fluxes in that density range. But due to the action of mixing on the body of fluid between the control surface and the sea-surface, transformation may differ from the integrated subduction. We find that vertical diffusive fluxes at the base of the winter mixed layer and in the seasonal thermocline can substantially modify transformation due to air–sea interaction and bring about an accommodation between it and the subduction rate. In high latitudes, an additional accommodation is achieved by lateral diffusive fluxes directed across the almost vertical isopycnals, typical of the deep, end-of-winter mixed layers of the sub-polar gyre. Finally we speculate on the likely nature and intensity of the mixing processes at work in the boundary layer of the ocean and their role in subduction and transformation.     

A method of simultaneous analysis of wind and temperature profile data over the water surface by use of the method of least squares

Priestley’s 1959 discussion concerning the estimations of momentum flux and of heat flux from profile observations of wind and temperature, stating that the closeness of the curve fitting is deceptive, is first critically re-examined. Then a method is proposed to estimate vertical flux of momentum and heat over the water surface, from the combined data of of wind speed and temperature are assumed to have similar log-linear profiles, and the most probable profiles are determined by applying the method of least squares simultaneously to wind and temperature data. Consequently, the most probable values of vertical flux of momentum and heat may be estimated to satisfy as much as possible observed data of both wind and temperature simultaneously. The coefficient of the linear term of the log-linear profile, which is treated as an indeterminate coefficient in this method, may be determined from each observed data as a function of stability length. By tentatively applying the method to Rider’s 1954 data it is found that the coefficient shows a characteristic behavior with the stability length.