Ice core oxygen isotope (δ¹⁸O) records from low-latitude regions preserve high-resolution climate records in the past, yet the interpretation of these ice core δ¹⁸O records is still facing difficulty due to the uncertainty of ice core dating. Here we present a new established δ¹⁸O time series from Qiangtang (QT) No. 1 ice core retrieved from the central Tibetan Plateau. Due to the vague seasonal signals in the QT ice core, we investigated the spectral properties of δ¹⁸O record with depth and discussed the implications of significant spectral power peaks in the QT ice core. We employed a variational mode decomposition (VMD) analysis for the upper part of the QT ice core to decompose the δ¹⁸O depth series in order to separate the El Niño Southern Oscillation (ENSO) mode, a signal strongly preserved in the QT ice core δ¹⁸O record. With this approach, we established a time series of 335 years (1677–2011 CE) for the upper 50 m of the QT ice core. Subsequently, we examined the frequency of the new established δ¹⁸O time series and detected strong signals of the bidecadal and multidecadal modes of Pacific Decadal Oscillation (PDO). The PDO consists of two modes with periods of approximately 25–35 years and 50–70 years, and we found that the 50–70 years periodicity has persisted since 1700 CE, succeeded by dominance of the 25–75 years periodicity after 1900 CE. Additionally, we analyzed the δ¹⁸O series of the QT ice core during the past century and determined that the increasing frequency of El Niño events is an important factor contributing to the increase in recent ice core δ¹⁸O.

来自低纬度地区的冰芯氧同位素 （δ¹⁸O） 记录保留了过去的高分辨率气候记录，但由于冰芯测年的不确定性，这些冰芯δ¹⁸O 记录的解释仍然面临困难。在这里，我们提出了从青藏高原中部回收的 Qiangtang （QT） 1 号冰芯中新建立的^{δ 18}O 时间序列。由于 QT 冰芯中模糊的季节性信号，我们深入研究了^{δ 18}O 记录的光谱特性，并讨论了 QT 冰芯中显着光谱功率峰值的影响。我们对 QT 冰芯的上部采用了变分模态分解 （VMD） 分析，以分解δ¹⁸O 深度序列，以分离厄尔尼诺南方涛动 （ENSO） 模式，该信号在 QT 冰芯δ¹⁸O 记录中得到强烈保留。通过这种方法，我们为 QT 冰芯的上部 50 m 建立了 335 年（公元 1677-2011 年）的时间序列。随后，我们检查了新建立的 δ¹⁸O 时间序列的频率，并检测到太平洋年代际振荡 （PDO） 的双年代际和多年代际模式的强烈信号。PDO 由两种模式组成，周期约为 25-35 年和 50-70 年，我们发现 50-70 年的周期性自公元 1700 年以来一直存在，继 1900 年之后 25-75 年周期的主导地位。此外，我们分析了过去一个世纪 QT 冰芯的 δ¹⁸O 系列，并确定厄尔尼诺事件频率的增加是导致近期冰芯δ¹⁸O 增加的重要因素。