论文标题

部分可观测时空混沌系统的无模型预测

Uncertainty in wave hindcasts in the North Atlantic Ocean

论文作者

Kodaira, Tsubasa, Sasmal, Kaushik, Miratsu, Rei, Fukui, Tsutomu, Zhu, Tingyao, Waseda, Takuji

论文摘要

准确的海洋表面波知识对于船舶设计至关重要。随着模型物理和数值资源的重大进步,最近的数值波后广播数据有可能为船舶设计过程中的波载估计提供环境条件。这项研究旨在量化最先进的数值波后广播产品中的模型不确定性,以洞悉Wave Hindcast用于船舶设计的应用。基于与北大西洋的波浪浮标以及与四个波模型产物的模型比较来推导模型不确定性。分布在西北大西洋和东北大西洋上的多个波浮标被认为是波浮标阵列,用于模型评估。通常,这四个模型在估计明显的波高$ H_S $的估计中均显示出非常好的和相似的精度。但是,模型$ h_s $偏离浮标,并且在$ h_s $> 10的极端波条件下相互偏离。还发现,在数值波模型和波浪浮标之间,平均波周期$ t_ {m02} $存在分歧。更具体地说,这些模型低估了东北大西洋$ H_S $> 10的极端波条件的$ T_ {M02} $。对于极端波条件的显着波高$ h_s $和平均波周期$ t_ {m02} $的关节概率密度函数(JPD)也得出了。在JPD中,满足$ H_S $> 10和8 <$ t_ {M02} $ <14的极端波条件的样品总数略有50%,尽管四种模型产品的平均值接近观察值。这项研究表明,对于更准确地重现极端条件是必要的进一步改进。对于模型的改进以及模型评估,有必要对高海状态及其波光谱信息进行更多测量。

Accurate ocean surface wave knowledge is crucial for ship design. With the significant advancements of model physics and numerical resources, the recent numerical wave hindcast data has a potential to provide environmental conditions for wave load estimation in the ship design process. This study aims to quantify model uncertainty in the state of art numerical wave hindcast products to get insight into the application of wave hindcast for ship design. The model uncertainty is deduced based on the comparison with the wave buoys in the North Atlantic as well as the inter-model comparison with four wave model products. The multiple wave buoys distributed over the Northwest Atlantic and Northeast Atlantic are considered as wave buoy arrays and used for model evaluations. All the four models in general showed very good and similar accuracy in the estimation of the significant wave height $H_s$. The model $H_s$, however, deviates from buoys and also deviate among each other for the extreme wave conditions of $H_s$>10. It is also found that there is disagreement for the mean wave period $T_{m02}$ between numerical wave models and the wave buoys. More specifically, the models underestimate $T_{m02}$ for extreme wave conditions of $H_s$>10 in the Northeast Atlantic. The joint probability density function (JPD) of the significant wave height $H_s$ and mean wave period $T_{m02}$ for the extreme wave conditions are also derived. Among the JPDs, the total number of samples that satisfies the extreme wave conditions of $H_s$>10 and 8<$T_{m02}$<14 varied by 50% although the mean value of the four model products is close to the observation. This study indicates further model improvement is necessary to more accurately reproduce the extreme conditions. For the model improvement as well as the model evaluation, more measurements of the high sea states and their wave spectra information are warranted.

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