In this study, we developed two high-resolution future ocean regional projection datasets for coastal applications in Japan, in which we made use of dynamical downscaling via regional ocean models with atmospheric forcing from two climate models (i.e., MIROC5 and MRI-CGCM3) participating in Coupled Model Intercomparison Project Phase 5 (CMIP5) under historical, representative concentration pathway (RCP) 2.6, and RCP8.5 scenarios. The first dataset was an eddy-resolving 10-km resolution product covering the North Pacific Ocean area and ranging continuously from 1981 to 2100, in which the Kuroshio current and mesoscale structures were reasonably resolved. The second dataset was a 2-km resolution product covering the regional domain surrounding Japan and comprising 10–15-year time slices, in which the coastal geometry and current structure were resolved even more realistically. An important feature of these datasets was the availability of reference datasets based on atmospheric and oceanic reanalysis data for cross-validation during the historical run period. Using these reference datasets, biases of regional surface thermal properties and the Kuroshio states during the historical run period were evaluated, which constitute important information for users of the datasets. In these downscaled datasets, the future surface thermal responses were generally consistent with those of their original data. Utilizing the high-resolution property of the downscaled data, possible future impact analyses regarding coastal phenomena such as strait throughflows, coastal sea level variability, and the Kuroshio intrusion phenomenon into bays (“Kyucho” phenomenon) were demonstrated and the important role of the Kuroshio state representation was indicated, which had proved difficult to analyze using the low-resolution projection data. Given these properties, the present datasets would be useful in climate change adaptation studies regarding the Japanese coastal region.

在这项研究中，我们开发了两个用于日本沿海应用的高分辨率未来海洋区域投影数据集，其中我们利用了区域海洋模型的动态降尺度以及来自两个气候模型（即MIROC5和MRI-CGCM3）的大气强迫在历史，代表性集中路径（RCP）2.6和RCP8.5情景下的耦合模型比较项目第5阶段（CMIP5）中。第一个数据集是覆盖北太平洋地区的分辨率为10 km的涡旋分辨率产品，范围从1981年到2100年连续不断，其中黑潮流和中尺度结构得到了合理解析。第二个数据集是一个2公里分辨率的产品，涵盖了日本周围的区域范围，包括10-15年的时间段，沿海地区的几何形状和当前结构得到了更加现实的解决。这些数据集的重要特征是基于大气和海洋再分析数据的参考数据集在历史运行期间可用于交叉验证。使用这些参考数据集，评估了历史运行期间区域表面热性质和黑潮状态的偏差，这为数据集的用户提供了重要信息。在这些缩小的数据集中，未来的表面热响应通常与其原始数据相一致。利用缩小后的数据的高分辨率特性，可以对海峡通流，沿海海平面变化，并证明了黑潮侵入海湾的现象（“ Kyucho”现象），并指出了黑潮状态表示法的重要作用，事实证明，使用低分辨率投影数据很难进行分析。鉴于这些特性，本数据集将在有关日本沿海地区的气候变化适应研究中很有用。