Abstract

Tree-ring stable oxygen isotope (δ¹⁸O_TR) demonstrates the enormous potential for revealing hydrological climate changes and large-scale atmospheric circulations. Here, we established the 210-year δ¹⁸O_TR chronology of Pinus tabulaeformis Carr. in Baotou, southwest Inner Mongolia, North China. The regional precipitation δ¹⁸O (δ¹⁸O_P) and June-July-August relative humidity (RH_JJA) were the two dominant environmental factors controlling the δ¹⁸O_TR changes. Since the 1930s, the increasing δ¹⁸O_TR values ​in the study region reflected the drying trend due to reducing precipitation and increasing temperature. The δ¹⁸O_TR series in Baotou generally exhibited stronger correlations with three Indian summer monsoon (ISM) indexes than three East Asian summer monsoon (EASM) indexes during 1948–2009 AD. However, the δ¹⁸O_TR record also significantly correlated with one EASM index. These results indicated that the Asian summer monsoon played an essential role in modifying the δ¹⁸O_TR values, and the ISM possibly had more considerable influence compared with the EASM. We also found that the δ¹⁸O_TR record had a higher correlation with the central-Pacific El Niño-Southern Oscillation (ENSO) than that with eastern-Pacific ENSO, probably because of the more substantial impact of the central-Pacific ENSO on the ISM.

摘要

树轮稳定氧同位素（δ ¹⁸ Ø _TR）演示揭示水文气候变化和大规模大气环流的巨大潜力。在这里，我们成立了210年δ ¹⁸ Ø _TR的年表油松卡尔。位于华北内蒙古西南部的包头。该区域降水δ ¹⁸ O（δ ¹⁸ Ø _P）和六月，七月，八月的相对湿度（RH _JJA）均是控制δ两个主要环境因素¹⁸ Ø _TR的变化。1930年以来，越来越多δ ¹⁸ Ø _TR研究区域的数值反映了由于减少降水和升高温度导致的干燥趋势。该δ ¹⁸ Ø _TR包头系列在公元1948年至2009年总体表现为三个印度夏季风（ISM）超过三个东亚夏季风指数（EASM）指数强相关性。然而，δ ¹⁸ Ø _TR记录也显著一个东亚夏季风指数呈正相关。这些结果表明，东亚夏季风在修改δ发挥了重要作用¹⁸ Ø _TR值，并与东亚夏季风相比，ISM可能有更多的相当大的影响。我们还发现δ ¹⁸ Ø _TR 记录与中太平洋厄尔尼诺-南方涛动（ENSO）的相关性高于与东太平洋ENSO的相关性，这可能是因为中太平洋ENSO对ISM的影响更大。