Constraints on the magnitude and patterns of ocean cooling at the Last Glacial Maximum - Supplementary material

Observation-based reconstructions of sea surface temperature from relatively stable periods in the past, such as the Last Glacial Maximum, represent an important means of constraining climate sensitivity and evaluating model simulations. The first quantitative global reconstruction of sea surface temperatures during the Last Glacial Maximum was developed by the Climate Long-Range Investigation, Mapping and Prediction (CLIMAP) project in the 1970s and 1980s. Since that time, several shortcomings of that earlier effort have become apparent. Here we present an updated synthesis of sea surface temperatures during the Last Glacial Maximum, rigorously defined as the period between 23 and 19 thousand years before present, from the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO) project. We integrate microfossil and geochemical reconstructions of surface temperatures and include assessments of the reliability of individual records. Our reconstruction reveals the presence of large longitudinal gradients in sea surface temperature in all of the ocean basins, in contrast to the simulations of the Last Glacial Maximum climate available at present.基于观测的古海面温度重建（针对过去相对稳定的时期，例如末次冰盛期（Last Glacial Maximum）），是约束气候敏感性、评估气候模式模拟结果的重要手段。首个针对末次冰盛期的定量全球海面温度重建成果，由气候长期调查、制图与预测（Climate Long-Range Investigation, Mapping and Prediction, CLIMAP）项目于20世纪70至80年代完成。自此之后，该早期工作的若干缺陷逐渐显现。本文基于冰川海洋表面多代用指标重建（Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface, MARGO）项目的数据，呈现一套更新后的末次冰盛期海面温度综合成果——后者被严格定义为距今23000至19000年的时段。本研究整合了微体化石与地球化学两类海面温度重建数据，并纳入了对各单条记录可靠性的评估。本次重建结果显示，所有大洋盆地均存在显著的海面温度经度梯度，这与当前已有的末次冰盛期气候模拟结果存在差异。