近日，中国海洋大学陈学恩团队最新研究报道了基于空间的轻推方法及其在全球潮汐同化中的应用。2024年5月9日出版的《大气科学进展》杂志发表了这项成果。

基于序列数据同化方法和卡尔曼增益矩阵的概念，研究人员提出了一种具有空间相关系数的潮汐同化新方法。空间相关的轻推方法既保留了传统轻推方法的优点，又便于直接确定更合理的轻推系数的空间分布。利用M₂潮汐分量作为对照，研究人员对正压环流和潮汐模式进行了海平面资料同化实验，估算了M₂潮汐分量的全球调和常数。结果表明，基于空间的微推方法可以有效地缓解潮汐相位滞后的偏差。

使用新方法同化后，M₂潮汐幅值和相位滞后的偏差比未同化情况分别减少47%和18%，比传统的轻推方法分别减少9%和11%。研究人员还将S-轻推方法应用于真实潮汐模拟，与传统方法相比，该方法的有效性有了显著的提高，这使得该方法对海洋潮汐环流的模拟具有重要价值。

据悉，潮汐作为海洋中至关重要的动力过程，在海洋和大气研究中都起着至关重要的作用，潮汐过程的精确模拟在潮汐环流模式中至关重要。

附：英文原文

Title: A Spatial-dependent Nudging Method and Its Application to Global Tide Assimilation

Author: li liu, Xueen Chen

Issue&Volume: 2024-05-09

Abstract: Tides, as a crucial dynamic process in the ocean, play a vital role in both the marine and atmospheric studies, thus accurate simulation of tidal processes is of utmost importance in tidal circulation models. Based on the sequential data assimilation method and the concept of the Kalman gain matrix, this paper proposes a new Nudging method with spatial-dependent coefficients for the tidal assimilation. The spatial-dependent Nudging method not only retains the advantages of the traditional Nudging method but also facilitates the direct determination of a more reasonable spatial distribution of Nudging coefficients. Utilizing the M₂ tidal constituent as an illustration, we conducted the assimilation experiments of sea level data to the barotropic circulation and tide model to assess the global harmonic constants of the M₂ constituent. The results demonstrate that the spatial-dependent Nudging method successfully mitigates deviations of tidal phase lag. Following assimilation using the new method, the deviations of the M₂ tidal amplitude and phase lag can be reduced by 47% and 18%, respectively, compared to the no-assimilation case, and up to 9% and 11%, respectively, in comparison to the traditional Nudging method. We also applied the S-Nudging method to realistic tidal simulations, and its effectiveness relative to traditional methods is significantly enhanced, making it highly valuable for the modeling of oceanic tidal circulation.

DOI: 10.1007/s00376-024-4062-5

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-4062-5viewType=HTML