昂仁金错末次冰消期GDGTs与温度数据

理解青藏高原古温度变化可以为评估在持续的全球变暖下未来的气候变化提供潜在的见解，并提高我们对古气候代用指标和模型模拟之间有争议的全新世温度变化的理解。在这里，我们展示了一个来自青藏高原南部昂仁金错的brGDGTs（支链甘油二烷基甘油四醚）的平均年均温（MAAT）记录，时间分辨率为115年，涵盖了过去的18,000年。我们的结果表明显示，brGDGTs主要来自陆地土壤，基于此重建的MAAT呈现出与年均太阳辐射和温室气体类似的变化，在冰消期显示出微弱的降温，并保持低温直到6 ka BP，然后升温至今，这与模型模拟相近。 10-6 ka BP期间的冷阶段在模拟中或相邻地区的大多数记录中都不存在。我们认为，这是对早全新世北大西洋涛动（NAO）正相位的反馈，这一时期青藏高原南部冬季冷空气频发并且降雪增加。考虑到过去18,000年当地年均和冬季太阳辐射的一致模式，以及过去40年冬季和年均温度之间的强相关性，这表明冬季可能对青藏高原的年温度至关重要。

Understanding past temperature changes on the Tibetan Plateau can provide potential insights for assessing future climate change under ongoing global warming, and improve our understanding of the debated Holocene temperature variations between paleoclimate proxies and model simulations. Here, we present a mean annual air temperature (MAAT) record derived from branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Lake Ngamring Jincuo in southern Tibetan Plateau, with a temporal resolution of 115 years, spanning the past 18,000 years. Our results demonstrate that brGDGTs are primarily sourced from terrestrial soils. The MAAT reconstructed based on these brGDGTs exhibits trends similar to those of mean annual solar radiation and greenhouse gases: it shows a slight cooling during the deglaciation, remained low until 6 ka BP, and then warmed up to the present, which aligns with model simulations. The cold phase during 10–6 ka BP is absent in most records from either model simulations or adjacent regions. We propose that this represents a feedback to the positive phase of the North Atlantic Oscillation (NAO) during the early Holocene, when winter cold air outbreaks were frequent and snowfall increased in southern Tibetan Plateau. Given the consistent patterns of local mean annual and winter solar radiation over the past 18,000 years, as well as the strong correlation between winter and mean annual temperatures over the past 40 years, this suggests that winter temperatures may play a critical role in the annual temperature of the Tibetan Plateau.