Evaluation of sea surface salinity observed by spaceborne microwave radiometer and applications to studies of the global water cycle

将Aquarius观测到的海面盐度（SSS）与Argo浮标和近海系泊浮标的全球观测结果进行比较，以评估SSS数据的质量并评估误差结构。Aquarius SSS与原位近地表盐度匹配，空间和时间间隔分别小于200 km和12 h。水瓶座观测到的SSS与原位盐度测量结果吻合良好。盐度残差（由Aquarius SSS减去Argo盐度定义）的均方根（rms）差为0.41 psu。利用日本海洋地球科学技术厅（JAMSTEC）的海洋数据优化插值系统和日本气象厅气象研究所（MRI/JMA）的海洋数据同化系统，对1 × 1°栅格上的月平均Aquarius SSS进行了比较。在40 S - 40 N上计算的均方根差为0.26 psu，这非常接近水瓶座任务的目标。

Sea surface salinity (SSS) observed by Aquarius was compared with global observation by Argo floats and offshore moored buoys to evaluate the quality of SSS data and to assess error structures. The Aquarius SSS was collocated with in situ near-surface salinity with spatial and temporal separations of less than 200 km and 12 h, respectively. SSS observed by Aquarius was in good agreement with in situ salinity measurements. The root-mean-square (rms) difference of the salinity residual, defined by Aquarius SSS minus Argo salinity, was 0.41 psu. The monthly averaged Aquarius SSS on 1 x 1 deg grids was also compared with outputs from the ocean data optimal interpolation system operated by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and the ocean data assimilation system of the Meteorological Research Institute, Japan Meteorological Agency (MRI/JMA). The rms difference calculated over 40 S - 40 N was 0.26 psu, which is very close to the goal of the Aquarius mission.