Increase in Deglacial Ocean Heat Content Linked to Contrasts in Extratropical Warming

IF 4.6 1区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geophysical Research Letters Pub Date : 2025-07-24 DOI:10.1029/2025GL115538

Chenyu Zhu, Lijing Cheng, Zhengyu Liu, Peter U. Clark

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引用次数: 0

Abstract

Proxy-based reconstructions suggest that equilibrium changes in global mean sea surface temperature (ΔGMSST) are nearly equivalent to changes in mean ocean temperature (ΔMOT) on glacial-interglacial timescales over the past 900,000 years. However, the underlying mechanisms responsible for this relationship remain poorly understood. Here we use simulations from Paleoclimate Modeling Intercomparison Project Phase 3 and 4 (PMIP3/4) to investigate equilibrium ΔMOT and its linkage to sea surface temperature changes between the Last Glacial Maximum (LGM, ∼21,000 years ago) and pre-Industrial. Results show that PMIP3/4 simulations generally underestimate proxy-based ΔMOT. Regression analysis reveals that LGM MOT is strongly modulated by mid-latitude SST cooling, with the Southern Ocean having a greater influence compared to other oceanic regions, thus helping explain why models with similar ΔGMSSTs exhibit significantly different ΔMOTs. Additionally, we find a strong relationship between simulated Antarctic sea-ice coverage and Southern Ocean SST changes, with implications for constraining sea-ice reconstructions.

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与温带变暖对比相关的去冰期海洋热含量增加

基于代理的重建表明，在过去90万年的冰期-间冰期时间尺度上，全球平均海面温度（ΔGMSST）的平衡变化几乎等同于平均海洋温度（ΔMOT）的变化。然而，对这种关系的潜在机制仍然知之甚少。在这里，我们利用古气候模拟比较项目第3和第4阶段（PMIP3/4）的模拟来研究末次极大冰期（LGM， ~ 21000年前）和工业化前的平衡ΔMOT及其与海面温度变化的联系。结果表明，PMIP3/4模拟普遍低估了基于代理的ΔMOT。回归分析显示，LGM MOT受到中纬度海温冷却的强烈调制，与其他海洋区域相比，南大洋的影响更大，从而有助于解释为什么具有类似ΔGMSSTs的模式表现出显著不同的ΔMOTs。此外，我们发现模拟南极海冰覆盖与南大洋海温变化之间存在很强的关系，这对约束海冰重建具有重要意义。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geophysical Research Letters 地学-地球科学综合

CiteScore

9.00

自引率

9.60%

发文量

1588

审稿时长

2.2 months

期刊介绍： Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.