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CO 2 ‐Induced Decoupling of Tropical Surface and Thermocline Water Temperature at the Onset of Interglacials
Author(s) -
Dong Liang,
Zhang Xu,
Jia Guodong,
Du Yan,
Li Li,
Li Qianyu
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl088805
Subject(s) - interglacial , thermocline , sea surface temperature , climatology , geology , decoupling (probability) , oceanography , environmental science , glacial period , atmospheric sciences , paleontology , control engineering , engineering
Tropical air‐sea interaction is important in global climate change; its behavior over geological history is poorly understood but can be explored by examining reconstructed sea surface temperature (SST) and thermocline water temperature (TWT). Here, deglacial‐interglacial air‐sea interactions over the past 500 ka were studied by comparing U K' 37 ‐derived SST 0‐30m and TEX H 86 ‐derived TWT 75m in a sediment core from the southern South China Sea. During deglacials, SST 0‐30m and TWT 75m varied synchronously toward interglacial peaks, while during the peak interglacials, TWT 75m decreased earlier than SST 0‐30m . These changes have been found ubiquitously in tropical oceans during the last two glacial‐interglacial cycles. We propose that the prolonged warm interglacial SST was probably sustained by the natural CO 2 “overshoot” greenhouse effect at the end of most terminations. The early interglacial TWT decrease following local insolation is driven by the decreasing downward heat transport efficiency induced by weakening wind stirring.