Variations in the mass and heat transported by the meridional overturning circulation (MOC) have important, well‐documented, influences on global and regional climate, weather, ecosystems, and coastal sea levels. However, continuous, high‐frequency, observations of these quantities have been limited to date. Multiple years of full‐depth daily observations from moored instruments in the South Atlantic at 34.5°S are combined with satellite observations to resolve the volume transports in both the upper and abyssal MOC cells, and the associated full‐depth meridional heat transport (MHT), on daily to interannual timescales. A newly developed method for combining satellite sea level observations with historical hydrographic measurements was used to estimate daily full‐depth ocean profiles of temperature in the ocean interior where mooring coverage is sparse. The average MHT during 2013–2017 is 0.5 PW, with a daily standard deviation of 0.8 PW. The MHT variability is most strongly driven by the geostrophic relative velocity contributions (horizontal density‐gradient changes). This variability is highly correlated with the volume transport variability of the MOC upper cell (r = 0.96) and modestly anti‐correlated (r = −0.52) with the abyssal cell variations. An empirical relationship between the MHT and MOC values was developed allowing the reconstruction of a longer MHT time series including the pilot array period (2009–2010). Seasonal variation of the MHT is significant, and results from strong variations of all terms (Ekman, barotropic, and baroclinic). Although the 2013–2017 shows an increasing MHT trend (0.14 PW/year), the longer time period record suggests that the apparent trend may simply be interannual modulation of MHT at 34.5°S.

中文翻译：

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大西洋经向翻转环流在34.5°S的每日热量输送的多年估算

经向翻转环流（MOC）传输的质量和热量的变化对全球和区域气候，天气，生态系统和沿海海平面有重要的，有据可查的影响。但是，迄今为止，对这些数量的连续，高频观测一直受到限制。通过南大西洋34.5°S处的系泊仪器进行的多年全深度每日观测与卫星观测相结合，解决了上层和深层MOC单元的体积输运以及相关的全深度经向热输运（MHT） ，从每天到每年的时间范围。一种新开发的方法将卫星海平面观测与历史水文测量相结合，用于估算系泊面积稀疏的海洋内部每日全深度海洋廓线。2013-2017年期间的平均MHT为0.5 PW，每日标准偏差为0.8 PW。MHT的变异性是由地转相对速度贡献（水平密度梯度变化）最强烈地驱动的。此可变性与MOC上层电池的体积传输可变性高度相关（r  = 0.96）和适度的反相关性（r  = -0.52）与深渊细胞的变化有关。建立了MHT和MOC值之间的经验关系，从而可以重建更长的MHT时间序列，包括试点阵列周期（2009-2010）。MHT的季节性变化非常显着，这是所有术语（埃克曼，正压和斜压）的强烈变化导致的。尽管2013–2017年的MHT趋势有所增加（0.14 PW /年），但更长的时间记录表明，明显的趋势可能只是在34.5°S时MHT的年际调制。