DataSheet_1_A global gridded ocean salinity dataset with 0.5° horizontal resolution since 1960 for the upper 2000 m.docx

A gridded salinity dataset with high resolution is essential for investigating global ocean salinity variability and understanding its role in climate and the ocean ecosystem. In this study, a new version of the Institute of Atmospheric Physics gridded salinity dataset with a higher resolution (0.5° by 0.5°) is provided by using a revised ensemble optimal interpolation scheme with a dynamic ensemble. The performance of this dataset is evaluated using “subsample test” and the high-resolution satellite-based data. Compared with the previous 1° by 1° resolution IAP product, the new dataset is more capable of representing regional salinity changes with the meso-scale and small-scale signals (i.e., in the coastal and boundary currents regions), meanwhile, maintains the large-scale structure and variability. Therefore, the new dataset complements the previous data product. Besides, the new dataset is compared with in situ observations and several international salinity products for the salinity multiscale variabilities and patterns. The comparison shows the smaller magnitude of mean difference and Root-mean-square deviation (RMSD) in basin scale for the new dataset, some differences in strength and fine structure of the “fresh gets fresher, salty gets saltier” surface and subsurface salinity pattern amplification trends from 1980 to 2017, a broad similarity for the salinity changes associated with El Niño-Southern Oscillation (ENSO) and a consistent salinity dipole mode in the tropical Indian Ocean (S-IOD). These results support the future use of gridded salinity data.

高分辨率格网盐度数据集对于研究全球海洋盐度变异性及其在气候与海洋生态系统中的作用至关重要。本研究中，通过采用修订的动态集成最优插值方案，我们提供了中国科学院大气物理研究所新版本的高分辨率（0.5°×0.5°）格网盐度数据集。该数据集的性能通过“子样本测试”以及高分辨率基于卫星的数据进行评估。与之前的1°×1°分辨率的IAP产品相比，新数据集能够更有效地描绘区域盐度变化，尤其是中尺度和小尺度信号（即沿海和边界流区域），同时保持了大型结构和变异性。因此，该新数据集是对先前数据产品的补充。此外，新数据集与现场观测和多个国际盐度产品在盐度多尺度变异性与模式上进行了比较。比较结果显示，新数据集在盆地尺度上的平均差异和均方根偏差（RMSD）较小，从1980年至2017年“淡者愈淡，咸者愈咸”的表观和次表观盐度模式增强趋势存在一些差异，与厄尔尼诺-南方涛动（ENSO）相关的盐度变化表现出广泛的相似性，以及在热带印度洋（S-IOD）中的一致盐度偶极模式。这些结果支持了未来格网盐度数据的使用。