Freshwater forcing of the Atlantic Meridional Overturning Circulation revisited
Freshwater forcing of the Atlantic Meridional Overturning Circulation revisited
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DOI：
10.1038/s41558-022-01328-2
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发表时间：
2022-04-07
影响因子：
30.7
通讯作者：
Clark, Peter U.
中科院分区：
文献类型：
--
作者：
He, Feng;Clark, Peter U.
淡水（FW）强迫被广泛认为是导致大西洋经向翻转环流（AMOC）减少的主要机制，AMOC是导致过去突然的千年尺度气候变化的气候转折点。然而，由于缺乏长期的AMOC观测和海平面上升和冰盖融化的不确定性，AMOC对FW强迫的反应还没有得到严格的评估，以推断过去的FW强迫。在这里，我们显示了一个温和的AMOC响应FW迫使（-50米海平面上升，从最后的冰消北方半球冰盖）在早到中期全新世-11700-6000年前。将这种静音AMOC响应包括在具有海洋-大气气候模型的全新世瞬态模拟中，提高了过去21，000年模拟温度和代理温度之间的一致性。这表明，AMOC可能不敏感FW通量和北极的清新，目前预计为21世纪末。
Freshwater (FW) forcing is widely identified as the dominant mechanism causing reductions of the Atlantic Meridional Overturning Circulation (AMOC), a climate tipping point that led to past abrupt millennial-scale climate changes. However, the AMOC response to FW forcing has not been rigorously assessed due to the lack of long-term AMOC observations and uncertainties of sea-level rise and ice-sheet melt needed to infer past FW forcing. Here we show a muted AMOC response to FW forcing (-50 m sea-level rise from the final deglaciation of Northern Hemisphere ice sheets) in the early-to-middle Holocene -11,700-6,000 years ago. Including this muted AMOC response in a transient simulation of the Holocene with an ocean-atmosphere climate model improves the agreement between simulated and proxy temperatures of the past 21,000 years. This demonstrates that the AMOC may not be as sensitive to FW fluxes and Arctic freshening as is currently projected for the end of the twenty-first century.