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表面海流和海面风在海上漂浮物漂移运动中起着至关重要的作用,但遗憾的是风和表面流在漂移运动的贡献系数并没有得到一致认可,因此本文以2011年南海部际联合海上搜救演习内部演习为例,根据海表面海流、海面风等海洋要素的实测资料,综合对漂移物的漂移特征进行分析,并对风、表面流的作用进行初步探讨。分析结果表明:风对不同类型漂移物的影响有着较大的差异,根据风和表面流与实际轨迹的拟合关系来看,人体模型和救生筏的风压漂移系数分别为0.01和0.07,而表面流在漂移物的漂移贡献系数均为1.0。 相似文献
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渤海海上溢油漂移扩散数值模拟研究 总被引：4，自引：0，他引：4
近几年渤海海上溢油突发事件频发,对海洋环境造成严重的污染。本文将业务化气象数值模型(Weather Research and Forecast model,WRF)、海流数值模型(Regional Ocean Model System,ROMS)的数值预报结果作为海洋环境驱动场,采用"油粒子"的海上溢油漂移扩散数值模拟方法,对在渤海发生的溢油扩散行为进行模拟预测。本文针对渤海溢油事件,设计敏感试验,研究不同风、流系数和网格分辨率对溢油扩散模拟结果的影响,获得适合于渤海的溢油数值模型参数,提高溢油漂移扩散预报的准确度,为海洋溢油应急处置和防灾减灾提供技术支持。 相似文献
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为了提高现有的海上搜救和绿潮漂移预测模型的预报精度,在2011年7月20日进行了一次落水人员、绿潮和无动力船漂移预测的海上试验。通过分析这三种海上漂移物运移轨迹的实验数据,确立了落水人员、绿潮、以及无动力船在海上漂移轨迹的主要影响因素。实验结果表明,落水人员和绿潮的漂移轨迹比较一致,基本都受限制于海流运动。其中,落水人员相较于绿潮来说受到潮流的作用比较大,风对绿潮的影响相比对落水人员的影响大。无动力船的漂移轨迹与落水人员和绿潮的漂移轨迹略有不同,受潮流往复作用较小。根据海上实验的结果,我们重新确立了搜救模型的中海流和风应力的参数,使得搜救模型的模拟结果更吻合于实验数据。 相似文献
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平潭近岸海域岸线曲折,周边岛礁众多,海底地形复杂,是福建省海难事故的高发区.本研究建立了平潭近岸海域海上目标物漂移轨迹的预测系统,该系统通过风场和流场的数值模型获取海面动力环境信息,采用拉格朗日算法实现对海上目标物漂移轨迹的预测追踪.其中海流模型采用ROMS（regional ocean modeling system）模型构建,模型水平方向上最高分辨率为100m,垂向上分为16层,并考虑干湿边界,以体现复杂海岸线和水深地形.通过验证分析,潮位、流速和流向的模拟平均绝对误差分别为0.20 m、0.12 m/s和26°.通过平潭近岸2个浮子实验,结果表明,浮子漂移过程中受潮流和局地地形的影响明显,对漂移模型在平潭近岸海域的适用性进行初步验证,浮子模拟轨迹与实际漂移过程基本吻合,模拟时段内最大偏差距离为2.8km,系统可以为平潭近岸海域海上突发事故应急决策提供参考. 相似文献
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为探讨海上搜救目标无动力渔船和落水人员在海水中的漂移规律,对现有海上搜救目标漂移轨迹预测模型进行评估与改进,国家海洋局南海海洋工程勘察中心于2011年2月和4月在广东近岸海域开展了3组模拟人和2组无动力船海上漂移试验。试验发现模拟人与无动力船大部分时刻的漂移轨迹位于下风向的右侧,80%以上的时刻漂移轨迹位于海流流向和下风向的矢量合成区间内。以漂移速度为应变量,流速和风速为自变量进行二元回归分析发现,广东海域的模拟人和无动力渔船的流致漂移参数约为1.0,风致漂移参数分别为0.019和0.038。 相似文献
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采用FVCOM数值模型的水动力模拟结果为拉格朗日粒子追踪漂移模型提供背景潮流场,模拟了秦皇岛近岸7个河口保守污染物在风和潮流作用下的漂移轨迹,分析了两种作用对污染物在近岸运移轨迹的影响关系。结果表明:无风状态下,以金山嘴为界,金山嘴以南各河口粒子漂移距离相对较长,受到近岸潮流的影响,粒子运动轨迹与秦皇岛近岸流场走向相符;1级风力下,漂移轨迹顺着潮流的方向移动,漂移距离甚至会小于无风状态,尤其是1级风力下的NE风和NWN风;在2-3级风力下,风的去向即为粒子漂移的方向,风力越大漂移距离越远、漂移范围也越大。 相似文献
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《海洋湖沼通报》2017,(6)
本文基于AP98风压漂移模型原理及其在实际风场中的一般算法,利用东方红2号船漂移实测数据,采用最小二乘法,拟合得到9个风压系数:顺风向斜率、截距、回归标准差分别为0.0544、-0.067、0.1;右偏侧风向3个系数分别为0.003、-0.27、0.11;左偏侧风向3个系数分别为-0.003、0.27、0.11。另外,利用蒙特卡洛和拉格朗日方法,基于所得系数模拟回报了其漂移轨迹,所得回报搜寻区域与真实漂移轨迹符合良好,从而表明所得系数可靠可用。本文工作为国内首次根据AP98模型原理对大型船只的风压特性展开研究,有一定的实际意义,可为后续相关研究提供借鉴。 相似文献
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A Leeway-Trace model was established for the traceability analysis of drifting objects at sea. The model was based on the Leeway model which is a Monte Carlo-based ensemble trajectory model, and a method of realistic traceability analysis was proposed in this study by using virtual spatiotemporal drift trajectory prediction. Here,measured data from a drifting buoy observation experiment in the northern South China Sea in April 2019,combined with surface current data obtained from the finite volu... 相似文献
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Severe hurricanes, such as Katrina, broke the mooring lines of a number of mobile offshore drilling units (MODU) deployed in the Gulf of Mexico and some of those MODUs went adrift. A drifting MODU may damage other critical elements of the offshore oil and gas infrastructure by colliding with floating or fixed production systems and transportation hubs, or by rupturing pipelines owing to their dragging anchors over the seabed. To avoid or mitigate the damage caused by a drifting MODU, it is desirable to understand the mechanics of the drift of a MODU under the impact of severe wind, wave and current and have the capability of predicting the trajectory of the drift. To explore the feasibility and accuracy of predicting the trajectory of a drifting MODU based on hindcast met-ocean conditions and limited knowledge of the condition of the drifting MODU, this study employed a simplified equation describing only the horizontal (surge, sway and yaw) motions of a MODU under the impact of steady wind, current and wave forces. The simplified hydrodynamic model neglects the first- and second-order oscillatory wave forces, unsteady wind forces (owing to wind gustiness), wave drift damping, and the effects of the body oscillation on the steady wind and current forces. It was assumed that the net effects of the oscillatory forces on the steady motion are insignificant. To verify the accuracy and feasibility of our simplified approach, the predicted drifting trajectories of two MODUs were compared with the corresponding measurements recorded by the global positioning system (GPS). 相似文献
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由海底摩擦与平均流速的平方成正比的公式,对底摩擦的性质(主要对拖曳系数C_0)进行讨论。研究在风暴潮和天文潮的条件下,海底摩擦与风速,风向和海深等因素的关系,得到有关奇异区的存在等结论,说明在整个海区内拖曳系数不为常数。 相似文献
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The drift motion of a maritime distress target is the collective result of the balance of forces that comes from wind, currents and waves. The drift properties vary from one type of object to another. The objective of this paper is to explore the leeway drift characteristics of typical Chinese offshore fishing vessels as well as evaluate the leeway drift model. First, a series of field experiments were conducted in South China Sea to provide data source. Next, nine leeway coefficients in AP98 leeway model were derived by the least square fitting based on the experimental data. Furthermore, another drifting dynamics model based on a balance of forces on the drifting vessel due to wind and currents, was also calibrated for comparison. Finally, two cases of drift trajectory and searching areas were simulated by the two different models through Lagrangian particle tracking and Monte Carlo techniques. Results indicate that the AP98 leeway model is in better accordance with the observation compared with the drifting dynamics model. Additionally, the simulation accuracy of AP98 leeway model can be improved to some extent especially when the probability of positive crosswind (POPC) is considered. Considering the large number of the typical offshore fishing vessels in South China Sea, and their high accident rate, the model coefficients for this type of vessels are expected to be implemented into more search and rescue (SAR) models by SAR organizations. 相似文献
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基于ROMS(Regional Ocean Modeling System)模式,对西北太平洋海域进行了水平分辨率高达4km的水动力环境数值模拟,该分辨率可以很好地分辨我国东海陆架环流以及中尺度涡旋等过程,此外模式考虑了8个分潮,模式结果很好地再现了黄、东海陆架环流等。基于模式结果,对"桑吉"号泄漏物质可能的扩散和迁移轨迹进行了数值模拟分析。在"桑吉"号沉船位置的表、底Ekman层内,释放拉格朗日粒子和示踪物来示踪"桑吉"号泄漏物质的可能影响范围。拉格朗日粒子和示踪物模拟结果表明:在未来3个月,"桑吉"号泄漏物质对我国黄海的影响较小,其主要随着对马暖流进入日本海和随着黑潮进入日本九州以南的太平洋海域。随着冬、春的季节转换,三个月后,北风会减弱,减弱风场的试验表明,风场减弱会减少泄漏物质向黄海的输送。5月份后黄海冷水团逐渐形成,由于斜压效应,在黄海深层水中会逐渐建立起气旋式环流,从而进一步阻碍了"桑吉"号泄漏物质向黄海的输送,该气旋式环流有利于"桑吉"号泄漏物质通过对马海峡向日本海的输送,而会抑制底层泄漏物质向我国黄海西侧的输送。 相似文献
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On predicting boat drift for search and rescue 总被引：1，自引：0，他引：1
A theoretical model for predicting boat drift for search and rescue missions is presented in this work. The drift model is based on the law of physics which govern the motion of a floating body in a given wind and surface current field. In terms of the empirical aerodynamics force coefficients of the boat or any other drifting object, external wind field, and current field, the drift velocity of the boat being searched for can be obtained. The uncertainty of the characteristics of the boat’s drift is evaluated by interval analysis of the uncertainties of the characteristics of the drifting boat and external forcing fields. The search area expansion and the source of uncertainty are systematically evaluated. The current statistical model-based operational definitions of leeway drift, leeway rate, leeway angle, divergence angle, leeway divergence, downwind component of leeway, and crosswind component of leeway are clarified in light of the presented theoretical model. The divergence angle and leeway divergence are evaluated through the interval analysis of the uncertainty of the parameters involved. 相似文献
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将一个三维湍能封闭模型应用于开阔海区的风暴潮，通过数值计算探讨了Ｔａｙｌｏｒ底摩擦二次率的拖曳系数随空间的分布及拖曳系数与水深、海底粗糙度、风向和风速等因素的关系。本文对底摩擦二次率的可靠性做了评价。 相似文献
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研究核电站附近海域漂流海藻的漂流路径对保障核电站冷源安全具有重要意义。本研究根据辽东湾东部海域漂流海藻的分布特征,构建该海域的二维水动力和粒子追踪数值预测、预报模型,基于近年实际观测的海流和潮位数据,对水动力模型进行验证,并根据2019年5月至8月释放北斗和GPS浮标采集数据,对该海域相同工况下的海藻漂移路径进行校验,均吻合良好。同时,对该海域7月大潮期,取水口附近海域的海藻堵塞风险进行了模拟分析,得到各不同工况下,漂流海藻到达取水口定义威胁区范围内的时间。结果表明,该数值模型能够对漂流海藻的漂移路径进行准确模拟,可为科学规避或有效减轻漂流海藻对核电站冷源取水口的堵塞风险提供技术支撑。 相似文献
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Wind-induced drift of objects at sea: The leeway field method 总被引：3，自引：0，他引：3
Øyvind Breivik Arthur A. AllenChristophe Maisondieu Jens Christian Roth 《Applied Ocean Research》2011,33(2):100-109
A method for conducting leeway field experiments to establish the drift properties of small objects (0.1-25 m) is described. The objective is to define a standardized and unambiguous procedure for condensing the drift properties down to a set of coefficients that may be incorporated into existing stochastic trajectory forecast models for drifting objects of concern to search and rescue operations and other activities involving vessels lost at sea such as containers with hazardous material.An operational definition of the slip or wind and wave-induced motion of a drifting object relative to the ambient current is proposed. This definition taken together with a strict adherence to a 10 m wind speed allows us to refer unambiguously to the leeway of a drifting object. We recommend that all objects if possible be studied using what we term the direct method, where the object’s leeway is studied directly using an attached current meter.We establish a minimum set of parameters that should be estimated for a drifting object for it to be included in the operational forecast models used for prediction of search areas for drifting objects.We divide drifting objects into four categories, depending on their size. For the smaller objects (less than 0.5 m), an indirect method of measuring the object’s motion relative to the ambient current must be used. For larger objects, direct measurement of the motion through the near-surface water masses is strongly recommended. Larger objects are categorized according to the ability to attach current meters and wind monitoring systems to them.The leeway field method proposed here is illustrated with results from field work where three objects were studied in their distress configuration; a 1:3.3 sized model of a 40-foot Shipping container, a World War II mine and a 220 l (55-gallon) oil drum. 相似文献