基于CMIP6模式对太平洋–北美型遥相关的评估分析

Assessment of Pacific-North American Teleconnection Based on CMIP6 Models

摘要: 太平洋–北美型遥相关(Pacific-North American teleconnection, PNA)是北半球冬季大气环流最重要的低频变率模态之一，其异常变化对北美乃至整个北半球中高纬度地区的气温、降水及极端天气事件具有深远影响。本研究以再分析资料集NOAA-CIRES和NCEP-NCAR Reanalysis 1为对照组，33个CMIP6模式为试验组，对模式结果进行评估分析。在评估过程中，首先通过时间多模式集合(Temporal Multi-Model Ensemble, TMME)和空间多模式集合(Spatial Multi-Model Ensemble, SMME)的两步筛选，构建了一套兼顾时间与空间模拟能力的模式遴选框架、形成了时空多模式集合(Temporal Spatial Multi-Model Ensemble, TSMME)，该集合是从参与评估的33个CMIP6模式中筛选出的一个模式子集。评估结果表明，TSMME在PNA指数时间相关性、年际振荡周期的再现以及空间模态的模拟精度等方面均优于或相当于另外两个集合，有效克服了传统集合平均因模式良莠不齐而导致的模拟能力受限问题，为后续研究奠定了可靠的模式基础。

Abstract: The Pacific-North American (PNA) teleconnection pattern is one of the most important low-frequency variability modes of boreal winter atmospheric circulation, and its anomalous changes exert profound influences on temperature, precipitation, and extreme weather events across North America and the mid-to-high latitudes of the Northern Hemisphere as a whole. This study uses reanalysis datasets NOAA-CIRES and NCEP-NCAR Reanalysis 1 as the reference set and 33 CMIP6 models as the experimental set to evaluate and analyze the model results. During the evaluation process, a two-step screening procedure was applied through the Temporal Multi-Model Ensemble (TMME) and the Spatial Multi-Model Ensemble (SMME) to construct a model selection framework that accounts for both temporal and spatial simulation capabilities, thereby forming the Temporal-Spatial Multi-Model Ensemble (TSMME). This ensemble represents a subset of models selected from the 33 CMIP6 models participating in the evaluation. Evaluation results demonstrate that TSMME outperforms or is comparable to another two ensemble methods in terms of the temporal correlation of PNA indices, the reproduction of interannual oscillation periods, and the accuracy of spatial pattern simulation, effectively overcoming the limitations of traditional ensemble averaging caused by uneven model quality, and providing a reliable model foundation for subsequent research.