Sea surface temperatures (SSTs) in the North Pacific exert a great influence on global climate and ecosystem changes. The Pacific Decadal Oscillation (PDO) is the leading mode of decadal SST variability in the North Pacific. The PDO-like variability at a millennial timescale during the Holocene is still poorly understood. In this study, the millennial-scale PDO-like variability during the Holocene is explored using model–data comparisons. To reduce the uncertainties caused by differential age controls, this study reconstructs the Holocene PDO-like index using two types of published proxy records, including 1) east–west SST contrast in the extratropical North Pacific and 2) PDO-related precipitation anomalies in East Asia. These two reconstructions reveal coherent changes in the PDO-like pattern during the Holocene, showing positive phases at 10.4–8.5 ka BP and 3.5–3.0 ka BP, and negative phases at 8.5–3.5 ka BP and 3.0–0.2 ka BP. Climate simulations suggest that the millennial-scale PDO-like variability is predominantly controlled by orbital forcing during the Holocene, leading to a positive phase of the PDO-like regime during the early Holocene. The positive phase of the PDO-like regime between 3.5 and 3.0 ka BP was probably caused by the internal feedback of the climate system, which the climate simulations fail to capture.

北太平洋的海表温度（SST）对全球气候和生态系统变化有很大影响。太平洋年代际振荡（PDO）是北太平洋年代际SST变异性的主导模式。全新世期间千禧年时间尺度上的PDO样变异性仍然知之甚少。在这项研究中，使用模型数据比较研究了全新世期间千禧年规模的PDO似的变异性。为了减少年龄差异控制带来的不确定性，本研究使用两种已发布的代理记录重建全新世的PDO类指数，包括1）温带北太平洋的东西向SST对比和2）PDO相关的东部降水异常亚洲。这两幅重建图显示了全新世期间PDO样模式的相干变化，显示了10时的正相。4–8.5 ka BP和3.5–3.0 ka BP，负相分别为8.5–3.5 ka BP和3.0–0.2 ka BP。气候模拟表明，全新世期间千禧年规模的PDO类变异主要受轨道强迫控制，从而导致了全新世早期PDO类体制的积极阶段。在3.5和3.0 ka BP之间的类PDO模式的正相很可能是由于气候系统的内部反馈所致，而气候模拟无法捕获这种内部反馈。