Lee Sang-Ki, Kim Dongmin, Gomez Fabian A, Lopez Hosmay, Volkov Denis L, Dong Shenfu, Lumpkin Rick, Yeager Stephen
NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, USA.
Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL, USA.
Nat Commun. 2024 Dec 6;15(1):10642. doi: 10.1038/s41467-024-54903-w.
The current state-of-the-art climate models when combined together suggest that the anthropogenic weakening of the Atlantic Meridional Overturning Circulation (AMOC) has already begun since the mid-1980s. However, continuous direct observational records during the past two decades have shown remarkable resilience of the AMOC. To shed light on this apparent contradiction, here we attempt to attribute the interdecadal variation of the historical AMOC to the anthropogenic and natural signals, by analyzing multiple climate and surface-forced ocean model simulations together with direct observational data. Our analysis suggests that an extensive weakening of the AMOC occurred in the 2000s, as evident from the surface-forced ocean model simulations, and was primarily driven by anthropogenic forcing and possibly augmented by natural variability. However, since the early 2010s, the natural component of the AMOC has greatly strengthened due to the development of a strong positive North Atlantic Oscillation. The enhanced natural AMOC signal in turn acted to oppose the anthropogenic weakening signal, leading to a near stalling of the AMOC weakening. Further analysis suggests that the tug-of-war between the natural and anthropogenic signals will likely continue in the next several years.
目前最先进的气候模型综合显示，自20世纪80年代中期以来，人为因素导致的大西洋经向翻转环流（AMOC）减弱已经开始。然而，过去二十年的连续直接观测记录显示，AMOC具有显著的恢复力。为了阐明这一明显的矛盾，我们通过综合分析多个气候和表面强迫海洋模型模拟以及直接观测数据，试图将历史AMOC的年代际变化归因于人为和自然信号。我们的分析表明，21世纪00年代出现了AMOC的广泛减弱，这在表面强迫海洋模型模拟中很明显，主要由人为强迫驱动，可能也受到自然变率的增强作用。然而，自21世纪10年代初以来，由于北大西洋涛动强烈正位相的发展，AMOC的自然分量大大增强。增强的自然AMOC信号反过来对抗人为减弱信号，导致AMOC减弱几乎停滞。进一步分析表明，自然和人为信号之间的较量在未来几年可能会继续。
