Temperature variabilty in the southeastern Black-Sea during 64-20ka BP

The Eurasian inland propagation of temperature anomalies during glacial millennial-scale climate variability is poorly understood but this knowledge is crucial to understanding hemisphere-wide atmospheric teleconnection patterns and climate mechanisms. Based on biomarkers and geochemical paleothermometers, a pronounced continental temperature variability between 64,000 and 20,000 years ago, coinciding with the Greenland Dansgaard-Oeschger cycles, was determined in a well-dated sediment record from the formerly enclosed Black Sea. Cooling during Heinrich events was not stronger than during other stadials in the Black Sea. This is corroborated by modeling results showing that regular Dansgaard-Oeschger cycles penetrated deeper into the Eurasian continent than Heinrich events. The pattern of coastal ice-rafted detritus suggests a strong dependence on the climate background state, with significantly milder winters during periods of reduced Eurasian ice sheets and an intensified meridional atmospheric circulation.

冰期千年尺度气候变率期间，温度异常在欧亚大陆内陆的传播机制目前仍不甚明晰，但该认知对于理解半球尺度大气遥相关型与气候机理至关重要。基于生物标志物（biomarkers）与地球化学古温度计（geochemical paleothermometers）分析，对原本为封闭环境的黑海的一则定年精准的沉积记录开展研究后发现，在64000至20000年前期间存在显著的大陆温度变率，该变率与格陵兰地区的丹斯果-奥什格尔旋回（Dansgaard-Oeschger cycles）相吻合。黑海区域海因里希事件（Heinrich events）期间的降温幅度并未强于其他冰阶时段。该结论得到模拟结果的佐证：常规丹斯果-奥什格尔旋回对欧亚大陆的影响程度较海因里希事件更为深远。沿岸冰筏碎屑的分布特征表明，其强烈依赖于气候背景态——当欧亚大陆冰盖规模缩减时，冬季气温显著偏暖，且经向大气环流得以增强。