NOAA/WDS Paleoclimatology - Heihai Lake Summer Temperature Reconstruction for the Last 5000 Years

We present a quantitative mean July temperature record spanning the last c. 5000 years from an alpine lake in south-western China. The reconstruction is based on the application of an established chironomid-based inference model using 100 lakes from the region. The reconstructed summer temperature changes are within 2.4°C of modern throughout the record. The results suggest that the summer temperature changes in south-east margin of the Qinghai–Tibetan plateau (QTP) predominantly responds to Asian Summer Monsoon influence, forced by summer insolation until c. 3200 cal. BP. Four cooling events, each separated by c. 500 years (between 3200 and 1600 cal. BP), were observed and these may correspond to the 500-year quasi-periodic solar fluctuation. The most recent cooling period, that is, ‘the Little Ice Age’, appears robust in the Heihai Lake record, providing further evidence that a hemisphere-wide forcing mechanism is possible for this climate event.

本研究报道了中国西南地区一处高山湖泊（alpine lake）的距今约5000年的定量7月平均温度序列。该重建结果依托一套已成熟的、基于区域内100个湖泊建立的摇蚊（chironomid）推断模型完成。整条记录中，重建的夏季温度与现代值的偏差均不超过2.4℃。研究结果表明，青藏高原（Qinghai–Tibetan Plateau, QTP）东南缘的夏季温度变化整体受亚洲夏季风（Asian Summer Monsoon）调控，且在约3200个校准碳年（cal. BP）之前均由夏季太阳辐射驱动。在3200至1600 cal. BP期间，共记录到四次降温事件，事件间隔约为500年，这或与500年准周期的太阳波动存在对应关系。在黑海湖（Heihai Lake）的记录中，最晚近的降温时段——即‘小冰期（Little Ice Age）’——信号显著，这为该气候事件存在半球尺度驱动机制提供了新的佐证。