Quantitative temperature and relative humidity changes recorded by the Lake Cuoqia in the southeastern Tibetan Plateau during the past 300 years
Quantitative temperature and relative humidity changes recorded by the Lake Cuoqia in the southeastern Tibetan Plateau during the past 300 years
复制标题
DOI：
10.3389/fevo.2023.1119869
复制
发表时间：
2023-02
影响因子：
4.2
通讯作者：
Tianlong Yan;Can Zhang;Haixia Zhang;Xiaoshuang Sun;Yilan Liu;Ruikun Liu;Wei Zhang;Cheng Zhao-Cheng-Zh
中科院分区：
文献类型：
--
作者：
Tianlong Yan;Can Zhang;Haixia Zhang;Xiaoshuang Sun;Yilan Liu;Ruikun Liu;Wei Zhang;Cheng Zhao-Cheng-Zh
湖泊沉积物中多种代用记录可为古气候重建和评估近期全球变暖在自然气候变率背景下的位置提供大量可提取信息。由于冬季湖面的冰盖性质，brGDGTs主要反映3 - 10月暖季温度的变化，并得到附近仪器资料的支持。我们重建的高分辨率温度在1700 - 1950年间呈现出持续的降温趋势，随后快速升温，与其他代用指标（如同一核心的正构烷烃和脂肪酸）平行，这也与先前发表的区域温度记录一致。脂肪酸氢同位素（δD）与区域树轮δ18O相似，可以记录大气降水同位素的历史，进一步指示区域相对湿度的变化。自1700年以来，我们的记录显示出长期的下降趋势，这与从Fe/Mn比值推断的湖泊水位下降一致。重建的温度和相对湿度组合格局在1950年以前呈现出一致的变化趋势，逐渐向冷干方向发展，之后开始脱钩。在1950年以前，温度和相对湿度的下降主要是由印度洋-太平洋和南亚大陆的日照和热对比驱动的。1950年以后，温度和相对湿度的脱钩可能与区域蒸发量增加以及人为温室气体和气溶胶排放增加有关。
High-elevation lakes on the Tibetan Plateau have the advantage of sensitive response to climate changes. Multiple proxy records in lake sediments can provide a large amount of extractable information for paleoclimate reconstructions and assessing the position of recent global warming within the context of natural climate variability. In this study, we reconstruct the climatic and environmental changes over the past 300 years from a remote alpine lake (Lake Cuoqia) in the southeastern Tibetan Plateau using multiple proxies including branched glycerol dialkyl glycerol tetraethers (brGDGTs), n-alkanes, elements, fatty acids and their hydrogen isotopes. Due to ice-cover nature of lake surface during winter, brGDGTs mainly reflect the variation in warm-season temperature from March to October, supported by nearby instrumental data. Our reconstructed high-resolution temperature showed a continuous cooling trend between 1700 and 1950 AD, followed by a rapid warming afterward, in parallel with other proxies such as n-alkanes and fatty acids in the same core, which is also consistent with previously published regional temperature records. The hydrogen isotope (δD) of fatty acids, similar to regional tree-ring δ18O, can record the history of atmospheric precipitation isotope and further indicate the variations of regional relative humidity. Our record exhibited a long-term decrease since 1700 AD, in accord with the decreasing lake level inferred from the ratio of Fe/Mn. The combined pattern of reconstructed temperature and relative humidity showed consistent changes before 1950 AD toward to a gradually cold-dry trend, whereas started to decouple afterward. Before 1950 AD, the declined temperature and relative humidity are mainly driven by insolation and thermal contrast between the Indian-Pacific Ocean and south Asian continent. After 1950 AD, decoupling of temperature and relative humidity may be related to the increased regional evaporation and human-induced emission of greenhouse gases and aerosol.