源区黑潮流量季节性变化的可预报性和目标观测研究

As the seasonal variation of the upstream Kuroshio transport has important impacts on regional climate, ocean circulation and ecosystem, it is of great significance to study its predictability and targeted observation problem. Recent studies show that initial errors play a vital role in affecting the upstream Kuroshio transport forecast and ocean background state affects the evolution of initial errors significantly. Therefore, it is worth investigating how initial errors affect the upstream Kuroshio transport prediction under different ocean background states. By using the Regional Ocean Modeling System (ROMS) and the conditional nonlinear optimal perturbation (CNOP) method, this project will investigate the following problems. Firstly, how initial errors in each season affect the prediction of the upstream Kuroshio transport will be investigated. The error-growth mechanism and the impacts of ocean background states on the evolution of initial errors will be specifically discussed, respectively. Then, the sensitive areas of targeted observation on improving the upstream Kuroshio transport prediction will be determined through the spatial structures of the CNOP-type errors. Adaptive observation networks will be further designed within the identified sensitive areas. This study is helpful to clarify the reason and mechanism causing the prediction uncertainties of the seasonal variation of the upstream Kuroshio transport and will provide guidance on operationally implementing adaptive observation in this region.

源区黑潮流量变化对局地气候、海洋环流及生态系统有重要影响，开展其可预报性和目标观测研究具有重要意义。初始误差是导致源区黑潮流量预测结果不确定性的重要原因，海洋背景状态在误差发展过程中起着关键作用。因而在不同季节海洋背景状态下探究初始误差对源区黑潮流量变化预报的影响有重要意义。为此，本项目拟基于复杂海洋模式（ROMS），利用条件非线性最优扰动（CNOP）方法开展如下研究：（1）在不同季节，利用CNOP方法探究初始误差对源区黑潮流量变化预测的影响，探讨误差增长机制及海洋背景状态季节差异对误差发展的影响；（2）基于CNOP型误差的空间结构特征识别源区黑潮流量变化的目标观测敏感区，并从应用角度出发，于敏感区内设计适应性观测网。本项目的实施既有助于弄清初始误差导致源区黑潮流量季节性变化预测不确定性的原因和机制，又能为该海区内观测系统的优化设计提供方法指导。

源区黑潮流量变化对局地气候、海洋环流及生态系统均有重要影响，目前其模拟与预测仍存在较大的不确定性。为此，本项目利用非线性最优化方法，从初始误差的角度开展了源区黑潮流量季节变化的可预报性与目标观测研究。项目按照预计研究计划执行，取得了如下进展：（1）在复杂模式中建立了能够处理高维变量的非线性优化系统，该系统具有良好的应用前景，已成功应用于源区黑潮、黑潮延伸体等可预报性研究，这为在业务化模式中开展研究提供了技术保障；（2）计算得到了对源区黑潮流量变异预报影响最大的初始误差，其具有局地性结构特征，主要位于吕宋岛以东区域，定量评估了初始误差对流量变异预报的影响程度，阐明了误差快速增长的物理机制；（3）确定了源区黑潮流量季节性下降的观测敏感区，于敏感区内构建了最优适应性观测网，最优适应性观测网将相关预测技巧提高了40%以上。本项目圆满完成了预定研究目标，共计发表论文6篇，其中SCI论文5篇。项目成果为提高源区黑潮流量变化的预测能力提供了科学支撑，所构建的最优适应性观测网对实现该海区内观测资源的优化配置具有重要的指导意义。