Little Ice-Age cooling in the Hengduan Mountains, China: A 600-year warm-season temperature reconstruction from tree-rings

The distributions of forest, ice and snow in the Hengduan Mountains of China have undergone significant changes due to ongoing climatic warming. To better understand the spatiotemporal pattern of temperature changes in the Hengduan Mountains we used tree-ring cores from multiple individuals of Larix speciosa Cheng et Law at five sites to develop a regional chronology and to establish the relationship between tree-ring radial growth and warm-season (May–September) mean temperature. The regional chronology accounts for 46.1% of the observed variance in the warm season and was used to reconstruct regional temperature levels back to 1420. Four cool intervals (1490 – 1570, 1590 – 1660, 1700 – 1790, and 1800 – 1880) indicate that the Hengduan Mountains experienced the Little Ice Age, and the changes were synchronous with cooling in the Tibetan Plateau and the Northern Hemisphere, demonstrating a well-defined Little Ice Age signal in the South Asian monsoon region.受持续气候变暖影响，中国横断山区的森林与冰雪分布已发生显著变化。为明晰横断山区气温变化的时空格局，本研究采集了5个采样点内多株怒江红杉（Larix speciosa Cheng et Law）的树轮样芯，以此构建区域树轮年表，并建立树轮径向生长与暖季（5月至9月）平均气温之间的响应关系。该区域树轮年表可解释暖季气温观测方差的46.1%，并被用于重建1420年以来的区域气温序列。研究识别出4个冷期（1490–1570年、1590–1660年、1700–1790年及1800–1880年），表明横断山区曾经历小冰期（Little Ice Age）；上述冷期变化与青藏高原及北半球的降温过程同步，证实南亚季风区存在清晰的小冰期信号。