NOAA/WDS Paleoclimatology - Biondi et al 2001 Pacific Decadal Oscillation Reconstruction

Climate in the North Pacific and North American sectors has experienced interdecadal shifts during the twentieth century. A network of recently developed tree-ring chronologies for Southern and Baja California extends the instrumental record and reveals decadal-scale variability back to 1661. The Pacific decadal oscillation (PDO) is closely matched by the dominant mode of tree-ring variability that provides a preliminary view of multiannual climate fluctuations spanning the past four centuries. The reconstructed PDO index features a prominent bidecadal oscillation, whose amplitude weakened in the late l700s to mid-1800s. A comparison with proxy records of ENSO suggests that the greatest decadal-scale oscillations in Pacific climate between 1706 and 1977 occurred around 1750, 1905, and 1947.

20世纪期间，北太平洋与北美区域的气候经历了年代际尺度的变迁。新近构建的南加利福尼亚与下加利福尼亚州树木年轮年表网络，拓展了器测气候记录的时长，揭示了可追溯至1661年的年代际尺度气候变率。太平洋年代际振荡（Pacific Decadal Oscillation, PDO）与树木年轮变率的主导模态高度吻合，该模态为我们了解过去400年间的多年际气候波动提供了初步视角。重建的PDO指数呈现出显著的双年代际振荡特征，其振幅在18世纪后期至19世纪中期有所减弱。通过与厄尔尼诺-南方涛动（El Niño-Southern Oscillation, ENSO）代用记录的对比可知，1706年至1977年间，太平洋气候的最强年代际振荡分别出现在1750年、1905年与1947年前后。