Ogasawara winter Sr/Ca and U/Ca data of coral core OGA-02-1 and PDO reconstruction (coral-geoduck index)

The Pacific Decadal Oscillation (PDO), the leading mode of sea surface temperature (SST) anomalies in the extratropical North Pacific Ocean, has widespread impacts on precipitation in the Americas and marine fisheries in the North Pacific. However, marine proxy records with a temporal resolution that resolves interannual to interdecadal SST variability in the extratropical North Pacific are extremely rare. Here we demonstrate that the winter Sr/Ca and U/Ca records of an annually-banded reef coral from the Ogasawara Islands in the western subtropical North Pacific are significantly correlated with the instrumental winter PDO index over the last century. The reconstruction of the PDO is further improved by combining the coral data with an existing eastern mid-latitude North Pacific growth ring record of geoduck clams. The spatial correlations of this combined index with global climate fields suggest that SST proxy records from these locations provide potential for PDO reconstructions further back in time.太平洋年代际振荡（Pacific Decadal Oscillation, PDO）是北太平洋中高纬海域海表温度（sea surface temperature, SST）异常的主导模态，其对美洲地区降水及北太平洋海洋渔业均具有广泛影响。然而，北太平洋中高纬海域中能够分辨年际至年代际尺度海表温度变率的海洋代用资料极为匮乏。本研究表明，取自北太平洋西部亚热带海域小笠原群岛的年纹层礁珊瑚冬季Sr/Ca与U/Ca记录，与近一个世纪以来的器测冬季PDO指数显著相关。通过将珊瑚数据与北太平洋东部中纬度海域已有的象拔蚌生长纹记录相结合，PDO的重建结果得到进一步优化。该综合指数与全球气候场的空间相关分析表明，上述两处海域的海表温度代用资料，为开展更长时间序列的PDO重建工作提供了潜在可能。