Distinct sources of interannual subtropical and subpolar Atlantic overturning variability
Distinct sources of interannual subtropical and subpolar Atlantic overturning variability
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DOI：
10.1038/s41561-021-00759-4
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发表时间：
2021-05-31
影响因子：
18.3
通讯作者：
Smith, Timothy
中科院分区：
文献类型：
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作者：
Kostov, Yavor;Johnson, Helen L.;Smith, Timothy
大西洋纬向翻转环流（AMOC）是区域和全球气候的关键，因为它在热量和碳的吸收和再分配中起着关键作用。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对海洋表面的自然和人为变化做出反应。然而，理解观测到的AMOC变化是具有挑战性的，因为环流受到多种因素的影响，这些因素相互影响，并且重叠的影响持续多年。在这里，我们重建和明确的属性在两个观测阵列的年际和年际AMOC变率的最近的历史表面风应力，温度和盐度。我们使用一个国家的最先进的技术，计算空间和时间变化的灵敏度模式的AMOC强度相对于多个表面属性从数值海洋环流模型约束的观测。虽然，在年际时间尺度上，在26度N的AMOC变率是压倒性的本地风应力的线性响应占主导地位，在副极地纬度的翻转变率是由风应力和表面浮力异常的综合影响。我们的分析提供了一个定量的亚极地AMOC变化的归因于温度，盐度和风的异常在海洋surface.Wind应力控制在大西洋纬向翻转环流在中纬度地区的年度变化，而表面浮力也事项在亚极地纬度，根据一个属性分析，使用的数值模式约束的观测阵列数据。
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 degrees 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.Wind stress controls annual variations in the Atlantic meridional overturning circulation at mid-latitudes, while surface buoyancy also matters at subpolar latitudes, according to an attribution analysis using a numerical model constrained by observational array data.