The Atlantic meridional overturning circulation (AMOC) is pivotal for regional and global climate due to its key role in the uptake and redistribution of heat and carbon. Establishing the causes of historical variability in AMOC strength on different timescales can tell us how the circulation may respond to natural and anthropogenic changes at the ocean surface. However, understanding observed AMOC variability is challenging because the circulation is influenced by multiple factors that co-vary and whose overlapping impacts persist for years. Here we reconstruct and unambiguously attribute intermonthly and interannual AMOC variability at two observational arrays to the recent history of surface wind stress, temperature and salinity. We use a state-of-the-art technique that computes space- and time-varying sensitivity patterns of the AMOC strength with respect to multiple surface properties from a numerical ocean circulation model constrained by observations. While, on interannual timescales, AMOC variability at 26° N is overwhelmingly dominated by a linear response to local wind stress, overturning variability at subpolar latitudes is generated by the combined effects of wind stress and surface buoyancy anomalies. Our analysis provides a quantitative attribution of subpolar AMOC variability to temperature, salinity and wind anomalies at the ocean surface.

大西洋经向翻转环流 (AMOC) 对区域和全球气候至关重要，因为它在热量和碳的吸收和再分配中发挥着关键作用。确定不同时间尺度上 AMOC 强度历史变化的原因可以告诉我们环流如何响应海洋表面的自然和人为变化。然而，了解观察到的 AMOC 变异性具有挑战性，因为环流受到多种因素的影响，这些因素共同变化并且其重叠影响持续多年。在这里，我们重建并明确地将两个观测阵列的月间和年际 AMOC 变化归因于最近的地表风应力、温度和盐度历史。我们使用最先进的技术来计算 AMOC 强度的空间和时间变化的灵敏度模式，该模式与来自受观测约束的数值海洋环流模型的多个表面特性有关。虽然在年际时间尺度上，26° N 的 AMOC 变率主要由对局部风应力的线性响应主导，但在亚极地纬度的翻转变率是由风应力和地表浮力异常的综合影响产生的。我们的分析提供了对海洋表面温度、盐度和风异常的亚极地 AMOC 变异性的定量归因。北纬 26° 的 AMOC 变异性主要由对局部风应力的线性响应主导，而在亚极地纬度的翻转变异性是由风应力和地表浮力异常的综合影响产生的。我们的分析提供了对海洋表面温度、盐度和风异常的亚极地 AMOC 变异性的定量归因。北纬 26° 的 AMOC 变异性主要由对局部风应力的线性响应主导，而在亚极地纬度的翻转变异性是由风应力和地表浮力异常的综合影响产生的。我们的分析提供了对海洋表面温度、盐度和风异常的亚极地 AMOC 变异性的定量归因。