The climate comprises an externally forced component and internal variability within the climate system. This variability arises from interactions among climate subsystems, significantly impacting climate change, particularly over the Tibetan Plateau (TP). Therefore, understanding the mechanisms governing TP temperature responses to internal variability is crucial. In this study, winter temperature components over the TP in response to internal variability and external forcing are distinguished using reconstructed monthly temperature data and large ensemble simulations from 11 CMIP6 coupled models spanning 1901 to 2014. Analysis reveals two cold periods (1901–1931, 1956–1999) and two warm periods (1932–1955, 2000–2014) within the internal-variability component from 1901 to 2014. These periods are significantly associated with the Atlantic Multi-decadal Oscillation (AMO) and Interdecadal Pacific Oscillation (IPO), explaining 38.9% of the winter temperature's internal-variability component over the TP. Manipulating AMO+ (AMO-) without IPO influence or IPO- (IPO+) without AMO impact intensifies the winter warm (cold) anomaly across the entire TP. This suggests that AMO and IPO contribute to the temperature's internal-variability component over the TP. Specifically, in winter, both AMO+ (AMO-) and IPO- (IPO+) induce a “− + −+” (+ − +−) Rossby wave train over Eurasia, influencing the East Asian trough, East Asian jet stream, Ural Blocking high, and the Siberian high, resulting in a warm (cold) anomaly over the TP. Moreover, our findings indicate that AMO and IPO collaboratively determine the cold or warm anomaly and its intensity over the TP in winter.

中文翻译：

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内部变率对青藏高原冬季气温波动的影响

气候包括外部强迫成分和气候系统内的内部变率。这种变异性源于气候子系统之间的相互作用，对气候变化产生重大影响，特别是在青藏高原（TP）。因此，了解TP温度对内部变化响应的机制至关重要。在本研究中，利用重建的月温度数据和 1901 年至 2014 年 11 个 CMIP6 耦合模型的大型集合模拟，区分了青藏高原冬季响应内部变率和外部强迫的温度分量。分析揭示了两个寒冷时期（1901-1931 年、1956 年） – 1999年）和1901年至2014年内部变率成分内的两个暖期（1932年至1955年、2000年至2014年）。这些时期与大西洋多年代际涛动（AMO）和年代际太平洋涛动（IPO）显着相关，解释了青藏高原冬季气温内部变率的38.9%。操纵无IPO影响的AMO+（AMO-）或无AMO影响的IPO-（IPO+）会加剧整个高原的冬季暖（冷）异常。这表明 AMO 和 IPO 对 TP 上的温度内部变异分量有贡献。具体而言，冬季，AMO+（AMO-）和IPO-（IPO+）都会在欧亚大陆上空诱发“− + −+”（+ − +−）罗斯贝波列，影响东亚海槽、东亚急流、乌拉尔阻塞高压和西伯利亚高压，导致青藏高原上空出现暖（冷）异常。此外，我们的研究结果表明，AMO 和 IPO 共同确定了冬季青藏高原的冷暖异常及其强度。