Contrasting Pacific Decadal Oscillation influence on ice core dust deposition across the Tibetan Plateau

Understanding the spatiotemporal variability of atmospheric dust over the Tibetan Plateau (TP) and its response to large-scale climate patterns is critical for comprehending regional climatic and environmental changes. Here, we present an annually resolved Ca²⁺ concentration record from the Qiangtang No. 1 Glacier spanning 1800–2011 CE to investigate the influence of the Pacific Decadal Oscillation (PDO) on dust deposition in the central TP. Correlation and wavelet analyses demonstrate a significant relationship between the QT Ca²⁺ record and reconstructed PDO indices derived from Asian proxies, with both exhibiting coherent pentadecadal periodicities. Combined with other TP dust records, our analyses reveal that the PDO has a regionally contrasting influence on interdecadal dust variability over the TP. Specially, the PDO exhibits a significant positive correlation with dust concentration records in the central and southern TP, whereas a negative correlation in the northwestern TP. This spatial pattern persists at least over the past millennium, as evidenced by long-term ice core dust records. During the positive PDO phases, intensified aridity in South Asia and enhanced atmospheric transport contribute to elevated atmospheric dust loading over the southern TP, while wetter conditions in Central Asia and weakened westerly circulation likely result in reduced dust level over the northwestern TP. These findings on the PDO's spatially heterogeneous influences offer new insights into how the PDO modulates the long-term dust variability across the TP.