Onset and maturation of Asian summer monsoon precipitation reconstructed from intra-annual tree-ring oxygen isotopes from the southeastern Tibetan Plateau
Chenxi Xu, Haifeng Zhu, Shih‐Yu Wang, Feng Shi, Wenling An, Zhen Li, Masaki Sano, Takeshi Nakatsuka, Zhengtang Guo
Abstract
Abstract We present a long-term seasonal tree ring cellulose oxygen isotope (δ 18 O c ) time series created by analyzing four segments (S1, S2, S3, and S4) per year during the period of 1951–2009 from southeastern Tibetan Plateau. This intraseasonal δ 18 O c reveals the onset and mature phase of the summer monsoon precipitation in this region. Analysis indicates that the δ 18 O c of S1 has the strongest correlation with precipitation during the regional monsoon onset (29–33 pentads, May 21–June 10, r = −0.69), and the δ 18 O c values for S2, S3, and S4 correlate strongly with June, July, and August precipitation, respectively. Combined δ 18 O c of S2, S3, and S4 shows the most robust correlation ( r = −0.82) with the mature-phase monsoon precipitation (June-July-August, JJA), passing rigorous statistical tests for calibration and verification in dendroclimatology. These results demonstrate the feasibility in using long-term intraseasonal δ 18 O c to reconstruct the Asian summer monsoon's intraseasonal variations.