| 引用本文: | 孙雅晨,杨孟菲,马小林,安芷生.2026.过去2Ma海水表层温度的演变[J].地球环境学报,17(3):724-738 |
| SUN Yachen,YANG Mengfei,MA Xiaolin,AN Zhisheng.2026.Evolution of sea surface temperature over the past 2 million years[J].Journal of Earth Environment,17(3):724-738 |
|
| 摘要: |
| 第四纪作为与人类演化最为密切的地质时代, 查明其温度的演化历史可以为理解不同时间尺度气候敏感性和准确预测未来气候变化提供重要参考依据。文章汇编了全球过去26条海水表层温度(SST)记录, 提供了过去2 Ma以来的标准SST曲线。结果显示在长趋势上全球平均SST在中布容气候事件(MBE)之前逐步下降约3 ℃, 并且与大气CO2解耦; MBE之后SST略微上升, 同时冰期旋回振幅增大。大气CO2下降和冰盖及其相关的正反馈过程并不能解释中更新世降温机制。轨道时间尺度上SST具有清晰的41 ka和100 ka周期, 还具有405 ka偏心率长周期, 可能与海洋热含量变化有关。未来解决中更新世SST和大气CO2在长趋势上的解耦和405 ka周期的成因, 需要更为精确的大气CO2重建结果和更为真实的全耦合气候模拟。 |
| 关键词: 更新世 海水表层温度 长期趋势 轨道尺度 偏心率长周期 |
| DOI：10.7515/JEE2023275 |
| CSTR：32259.14.JEE2023275 |
| 分类号: |
| 基金项目:国家自然科学基金项目（42176094) |
| 英文基金项目: |
|
| Evolution of sea surface temperature over the past 2 million years |
|
SUN Yachen1，2，YANG Mengfei3，MA Xiaolin1，AN Zhisheng1
|
|
1. State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061 , China ； 2. University of Chinese Academy of Sciences, Beijing 100049 , China ； 3. State Key Laboratory of Continental Evolution and Early Life, Department of Geology, Northwest University, Xi'an 710069 , China
|
| Abstract: |
| Background, aim, and scope The Quaternary period, closely associated with human evolution, holds pivotal importance in understanding the sensitivity of climate change across different time scales and accurately predicting future climate variations. This study aims to establish an average sea surface temperature (SST) stack over the past 2 Ma and reveal its orbital and long-term trends, as well as the potential driving mechanisms. Materials and methods We compiled SST records from 26 sites across different oceanic regions. To ensure the robustness of the SST stack, several selection criteria were applied: (1) all records span over 800 ka with a temporal resolution finer than 10 ka, suitable for orbital-scale analyses; (2) only SST reconstructions based on Mg/Ca ratios and long-chain unsaturated alkenone (UK'37) were included, excluding those derived from other proxies; (3) all records are anchored to astronomical ages calibrated by benthic or planktonic foraminiferal δ18O, providing a unified chronological framework. Results In the long-term trend, the global SST gradually decreased by approximately 3 ℃ before the Mid-Brunhes Event (MBE) and decoupled from atmospheric CO2. After the MBE, SST slightly increased, while the amplitude of glacial-interglacial cycles increased. SST exhibits clear cycles at orbital time scales, including periods of 41 ka and 100 ka, as well as the 405 ka eccentricity long period. Discussion Despite clear long-term changes in global SST since the Quaternary, the mechanisms behind these trends remain uncertain. Orbital forcing and changes in atmospheric CO2 alone cannot fully explain the observed cooling, suggesting the involvement of other processes such as ice sheet dynamics. Uncertainties remain regarding the mechanisms behind Quaternary orbital-scale climate variations, including the origins of the 41 ka and 100 ka cycle and the transition from the 41 ka to 100 ka cycle. The 405 ka eccentricity cycle influences SST variability, potentially amplified by ocean carbon reservoirs. Additionally, the linear correlation between ocean heat content and SST suggests a modulation of high-frequency precession signals, enhancing the expression of eccentricity-paced SST variability. Conclusions We investigate the long-term and orbital-scale variability of sea surface temperature of Quaternary and explore its potential driving mechanisms. These findings enhance our understanding of climate sensitivity and the dynamic processes of Quaternary climate changes. Recommendations and perspectives Future research endeavors will necessitate precise atmospheric CO2 reconstructions and refined fully coupled climate simulations to further elucidate the intricate relationships between SST and atmospheric CO2. Investigating the evolution of Quaternary climate from the perspective of hemispheric asymmetry may provide fresh insights into the dynamic processes governing climate changes during this epoch. |
| Key words: Pleistocene sea surface temperature long term trend orbital timescale eccentricity long period |
